STICKY: -=FAQ=- EF LENS FAQ -READ FIRST- Before asking "What Lens?"

FORUMS Canon Cameras, Lenses & Accessories Canon EF and EF-S Lenses
Thread started 21 Jul 2005 (Thursday) 08:44   

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Welcome to the EF Lens FAQ thread.

Here you will find many answers to the most commonly asked questions regarding the Lenses and lens accessories for EOS Camera and systems.

Please take the time to search through the links in this section BEFORE posting a new thread.


-=Deciding on your next lens? - READ THIS FIRST=-

-=Deciding on your next lens? - READ THIS NEXT=-
---=Seven considerations when buying glass=---

-=Deciding on Focal Length? Tamron's Focal Length Comparison page=-external link

-=Teleconverters De-Mystified=-

-=UV / Protective Filter? Should I use them?=-

-=Opinions=-Best Lens for given price range

-=LINKS =- Canon EF Lens Links

-=EOS Equipment Reviews=-

-=Lens Adapters =- Adapt Non-EF lenses to your EOS digital

-=Zeis Jenna Lenses =- Buying Guide

-=Choosing a Macro Lens=- by Jack Rabin

-=Why and How are Constant Aperture Zooms made?=-

-=What are drop in filters?=-

-=Explain Canon Image Stabilization?=-

-=Why are the edges of my photo Dark? What is "light fall off"?=-

-=HOW TO Perform a lens focus test=-

-=Lens Focal Length and Crop Factors=-

-=Infra Red Lens Info & Options=-

-=What do you recommend for lens cleaning?=-

-=Alternate Lens Caps for Super Telephotos: or, Can I use Tupperware for a lens cap?=-

-=Tripod ring mounts - the definitive list=-



-=Top Ten=- Member recommended lens section.

This sticky thread lists the -=Top Ten=- Member recommended lens POLLS for your ease of viewing and research.

Here you will find links to POLLS that you can use to find information on lenses for different purposes. You can also contribute to these POLLS by voting! :)

Here are our First -=Top Ten=- lists;

-=Top 10=- Recommended Starter Lenses

-=Top 10=- Recommended WalkAround Lenses-=NEW!=-

-=Top 10=- Recommended Portrait Lenses

-=Top 10=- Recommended wildlife Primes

-=Top 10=- Recommended wildlife Zooms

-=Top 10=- Recommended Indoor Sports/Event Lenses

-=Top 10=- Recommended Outdoor/Arena Sports/Event Lenses

-=Top 10=- Most USED Dedicated Macro Lenses


*please PM CDS to ahve a review added to this list of links

Canon EOS Lenses:

EF 100-400mm f/4.5-5.6LIS USM

EF 70-300mm f/4.5-5.6DO IS USM

EF 70-200mm f/2.8LIS Vs. Sigma 70-200mm f/2.8 EX HSM

EF 85mm F/1.2L Review

EF 135mm F/2.0L & EF 1.4x Extender Review

EF 70-200mm F/4L

EF 35mm f/1.4L

EF 35mm f/1.4L

EF 28mm f/1.8 USM

EF 200mm f/1.8L

EF 500mm f/4L IS

Head to Head Comparisons!

EF 70-200mm f/2.8L IS MkII with 2X T-Con Vs. 100-400mm @ 400mm

EF 100-400mm f/4.5-5.6LIS USM Vs. Sigma 150-500mm f/4-6.3 OS HSM

EF 100-400mm f/4.5-5.6LIS USM Vs. Sigma 50-500mm f/4-6.3 EX HSM

EF 100-400mm f/4.5-5.6LIS USM Vs. Sigma 50-500mm f/4-6.3 EX HSM Version 2 By LightRules

EF 400mm f/5.6L Vs EF 100-400mm f/4.5-5.6LIS USM

-=Battle of the 500mm Primes=- EF 500mm f/4L IS Vs. Sigma 500mm f/4.5 EX HSM

EF300mm f/4L IS Vs. EF 400mm f5.6L A discussion and review

Sigma 120-300mm f2.8 EX HSM Vs. EF 100-400mmL IS Review

EF 70-200mm f/2.8LIS Vs. Sigma 70-200mm f/2.8 EX HSM

EF 17-40 f/4L vs. 18-55 EFS

EF 24-70mm f/2.8L Vs. Sigma 24-70mm f/2.8 EX

Sigma 55-200 vs Tamron 55-200

Third Party Lens Reviews

Sigma 80-400mm OS EX

Tamron AF SP 28-75/2.8 XR Di LD

Sigma 70-200mm f/2.8 EX HSM Vs. EF 70-200mm f/2.8LIS

Zenitar Wide Fish eye

Sigma 150mm f/2.8 EX HSM Macro

Sigma Sigmonster 300-800mm f/5.6 EX

Another Sigma Sigmonster 300-800mm f/5.6 EX

Sigma 120-300mm f2.8 EX HSM A very thorough Review

Sigma 50-150mm f2.8 APO DC EX HSM first impressions

Post #1, Jul 21, 2005 08:44:55

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Macro Lens Comparisons by Working Distance vs. Price

Choosing a Canon macro lens by working distance vs. price
Most macro lenses render images with satisfying contrast. And after all, contrast is sharpness. Canon, Nikon, Minolta, Olympus, Pentax, Sigma, Tamron, and Tokina, Zeiss, etc. macro lenses are all sharp. Little is gained obsessively comparing macro lens brands and focal lengths. An alternative way to choose a lens is by comparing subject working distance when at close focus 1:1 magnification versus price. Macro lenses optimize sharpness across a flat image field at minimum focus distance, with low lens curvature distortion. Macro lens performance does vary at normal subject distances. The following are my impressions at close focus working distances.
What is working distance? Working Distance (WD) is the distance from the lens front objective to subject (without hood) when at closest focus, or 1:1 life size reproduction.
WD = published minimum focus distance specified for a lens - lens length - distance from lens mount flange to sensor/film plane (approx. 4.4 cm for Canon EOS system).
Lens manufacturers publish minimum focus distance (MFD): the closest focus distance from the sensor/film plane to the subject. MFD is less useful than knowing WD. Along with light loss (effective aperture), WD is a limiting factor using macro lenses . Get as much WD as you need and can afford.

1x life size WD compared with lens price. Macro lens price points align with WD more than other features. Major price deviations are for faster apertures, internal focusing floating elements, and image stabilization.
35mm Tokina f/2.8 macro est 3.5 cm WD @ $300
60mm EF-S f/2.8 macro USM = 9. cm WD @ $400
60mm Tamron f/2 Di II LD IF est 10. cm WD @ $500
70mm Sigma f/2.8 EX DG macro = 11.2 cm WD @ $500
100mm EF f/2.8 USM macro = 14.9 cm WD @ $520
100mm EF f/2.8L IS macro USM = 14.6 cm WD @ $945
150mm Sigma EX IF macro HSM = 19.4 cm WD @ $730
180mm EF f/3.5L USM = 25 cm WD @ $1,370
180mm Tamron macro = 26 cm WD @ $690

Other lenses
TS-E 24mm Canon f/3.5L II (+1.4x TC & ext. tube) @$1,990
50mm Canon f/2.5 1:2 Compact macro @265
50mm Zeiss Makro-Planar f/2 ZE 1:2 macro @ $1,290
65mm Canon MP–E 65mm f/2.8 1-5x macro @930
TS-E 90mm Canon f/2.8 (+1.4x TC & ext. tube) $1,210
100mm Zeiss Makro-Planar T* f/2 ZE 1:2 macro @ $1,850
300mm Canon f/4L IS (+2 Diopter 500D & 1.4x TC) @$1,275

Internal focus (IF). Determine if you can afford an internal focus floating element lens design. The 90-100-105mm ‘price-point’ macro lens offerings from Tamron, Sigma, and Tokina are satisfactorily sharp, but their lens barrels extend in length during focus. Decide for yourself if barrel extension affects your photography. A lens barrel that does not extend during close focus is a $100 convenience. Barrel extension doesn’t affect image quality, but impacts focusing on insects, which exhibit evasive behavior when detecting nearby shadows. Actual focal length at close focus is less than stated on the lens for IF floating element macro lenses.

APS-C sensor & macro lens focal length vs. field-of-view
Ignore the impact of APS-C sensor size field-of-view crop factor (FOVC) on lens effective focal length when selecting a macro lens for use at close focus distances. Sensor FOVC is relevant at normal photography distances, not close up. Choose a macro lens for its handling, features, and working distance. How focal length FOVC affects subject framing is more important at normal photography distances.

Manual and infinity focus. Most macro lenses focus continuously from close-up to infinity (not Canon MP-E 65mm). This enables alternative uses for macro lenses, but slows auto focus and leads to focus hunting on low contrast subjects or in lower light. This is normal and expected because optical elements must travel farther inside the lens barrel moving between close and infinity focus. Once they miss and defocus, they really defocus. Macro photographers manually focus extensively. Many Canon bodies have coarse focus screens. During manual focus the screens snap decisively in or out at the precise point of focus. FOVC cameras have smaller, darker, viewfinders compared to more advanced or full 35mm frame models. Viewfinder brightness and size have a greater impact on focusing and composition than whether the camera has 35mm or smaller sensor.

60mm Canon EF-S f/2.8 macro USM = 9cm+ WD. While longer macro lenses are better WD values, this is wonderful when you want 50-60mm focal length. This petite lens has world class resolving power way above its price, uses Canon’s best lens coatings, has a circular aperture which renders nice out-of-focus areas between f/2.8-5.6, and Canon’s best Ring USM focus motor. It is portable, discreet, and hand-holdable. The 60mm is limited to EF-S mount cameras, while the Sigma 70mm can be used on any camera. Sometimes 60mm has insufficient WD, or camera and photographer casts shadows on the subject. Users respecting the Nikon 60mm f/2.8 micro Nikkor waited years for Canon to make an equal. It happens to be EF-S. Carry the Canon EF-S 60mm macro: a) when using EF-S mount body; b) for pocket portability field or travel use without tripod; c) handholding in lower light at slower shutter speeds with less camera shake than longer lenses; d) in a limited three lens travel kit (e.g., 17-55mm and 70-300mm) - the EF-S 60mm becomes lower (if not quite low) light lens as well as close-up; e) using as studio portrait or product lens. The EF-S 60mm is Canon’s only USM macro where filter removal is not necessary when attaching Canon 14EX or 24EX macro flash. Hood purchase is extra. Canon 50mm Compact macro f/2.5 shares 52mm thread feature.

100mm Canon macro EF USM = 15cm WD. You pay over $100 to add 5cm WD from Canon 60mm to 100mm. 5cm is a 50% WD distance increase. 90-105mm is considered the most flexible focal length macro for wide variety of needs. With IF floating internal elements, the Canon EF 100mm USM has a shorter actual focal length at 1:1 reproduction, likely 80mm+/-, maintaining a good field of view at 15cm WD. This is an excellent flexible lens. Commonly used for medium telephoto or portraits, though sometimes almost too ‘clinical’ in rendering. It is honest; revealing skin blemishes. Hood must be purchased extra. Better Canon Ring USM focus motor. Everyone respects this lens.
Almost double your cost for the 100mm f/2.8L IS version, which offers outstanding hand hold-ability, a circular aperture, hood, weather resistance, snappy AF speed for a macro lens, and AI Servo II AF and distance feedback to 1D Mark IV and 7D bodies. Wonderful improvements if you hand hold, and if budget allows.

150mm Sigma macro HSM = 20cm WD. Pay $200 additional for another 5cm WD increase from the Canon 100mm. The Sigma 150mm comes with a hood, tripod collar, HSM auto focus with full-time manual override (I manually focus much of the time), making it an excellent lens, if focal length fits needs. It is a Sigma lens contributing to photography performance - not another a ‘me-too’ price-point product. There is nothing wrong with this lens. It has internal focus so lens barrel length does not change during focus, unlike the Sigma 105mm. The Sigma 150mm takes beautiful photos and promises to be popular. The color rendition tends to warmer yellow tones. The Sigma 150mm stops down to f/22. Most users never have enough light to stop down that far, and diffraction limits sharpness even if light permits stopping down to f/22+. Thus, for most users this is a non-issue. But some users of Canon 180mm macro do stop down beyond f/22, and the Sigma does not. A Canon 72mm Macro Lite thread adaptor is needed to connect the Canon 14 EX or 24 EX macro flash.

180mm Canon macro f/3.5L EF USM = 25cm WD. Pay $550 more for the next (last) 5cm WD gained from the Sigma 150mm. Good for bugs and snakes. The last macro lens you’ll ever buy (unless you need greater magnification from the Canon MP-E65mm 1-5x). It is a ‘L’uxury lens. Optimized for close focus, it is not in Canon’s top sharpness league at normal distances to infinity. It is not even Canon’s most resolving macro lens. Its mainfeature is working distance. Other features include: a) Canon’s best lens coatings of its time. b) Unlike most macro lenses losing two f/stops of exposure when close focused, the 180mm L loses 1 1/3 stops. Thus, the f/3.5 aperture is not a disadvantage compared to f/2.8 lenses. c) It’s big and long and prefers to be used tripod mounted, except when butterfly hunting. d) Maintains optical sharpness and low diffraction stopped down beyond f/22. e) Ultimate WD. The longer focal length makes it easier to compose shots. Isolate subjects, eliminate clutter, and get the lens plane position parallel to where you want the maximum depth of field on a subject. f) Works well with the Canon 1.4x teleconverter, for 140% life size at the lens’ close focus. Back away from 25cm close focus and still obtain life size reproduction. With the 1.4x TC, manual focus is required under 80cm. g) A Canon 72mm Macro Lite thread adaptor is needed to connect the Canon 14 EX or 24 EX macro flash.

180mm Tamron = 26cm WD. Tamron is the longest WD versus price value winner, but I did not use it because a non-standard lens front filter adjuster may prevent using the MT 24-EX Macro Flash.

Other Lenses
Wide angle, extension tubes, and Tilt-shift lens close-ups. Using close focusing wide-angle lenses with extension tube enable ‘thing in its environment’ close-ups. These are useful, sometimes stunning, and popular for environmental documentary photography; pulling viewers into the frame. Lenses include Canon 17-40mm f/4L, 16-35 f/2.8L (native magnification about 0.22x), Sigma 15mm f/2.8 Fisheye, Sigma 17-70 f/2.8-4.5. You lose infinity focus. The Tokina fisheye 10-17mm f/3.5-4.5 has very good native magnification for stunning thing in its environment close ups.

The Canon TS-E 90mm Tilt-Shift lens has native 0.29x magnification and the TS-E 24mm f/3.5L II has native 0.34x. Combined with a 1.4x teleconverter and/or extension tubes, TS-E lenses make outstanding, versatile, costly, close-up lenses for flowers in the field to tabletop still life close-ups. These lenses overcome depth of field limitations, at moderate f/stops, posed by macro lenses. The Gaussian blur optical design of the TS-E 90mm renders pleasing out-of-focus areas rivaling Canon’s lenses most appreciated for their fine out-of-focus area qualities.

Manual stop-down and manual focus lenses. Some users buy Nikon-EOS, Olympus OM-EOS, Leica-EOS mount adaptors and use these lenses as manual focus & manual stop-down macro lenses on their Canon cameras. Others use normal lenses with reversing rings. These are esoteric fun, sharp, good in a studio, sometimes expensive, and not too convenient for fast-pace fieldwork. The Zeiss 50mm and 100mm Makro lenses only achieve 0.5x life size reproduction, and are expensive, but highly regarded for image quality among manual focus Canon macro lenses.

The Canon 50mm f/2.5 1:2 Compact macro has a fast maximum aperture. It is a rugged and easy to carry lens, highly resistant to flare due to recessed objective, moderately priced, and available used for $200. If you do not have an EF-S mount body, this is what’s available cheaply in EF mount in normal focal length. While only achieving ½ life size, it is regarded for uses such as distortion free product photography and copy work. This lens is easy to carry in a pocket walking about. The color rendition is not as good as the EF-S 60mm macro. The lens barrel extends during focusing.

The Canon MP–E 65mm f/2.8 1-5x Macro is a specialized macro lens beginning at 1x life size reproduction and extending to 5x reproduction. It is designed, and succeeds, as an easier to use and operate alternative to bellows. Since it does not focus to infinity, it is not considered here, and can be evaluated at many other web information sites.

Canon EF 300mm f/4L IS (or telephoto zoom lenses) for dual use field close-ups.
There are a number of reasons why a Canon 300mm f/4L IS (or Canon 100-400mm L IS, 70-300mm IS, 70-300mm L IS, or 70-200mm L IS) lenses with a 1.4x TC and/or 500D +2 diopter work are well suited for field close-ups. The Canon 180mm f/3.5L macro is a stunning lens. But it prefers a tripod. The IS lenses offer hand holding benefits. a) If you are ‘never close enough,’ prefer giving subjects space, like using a tele or tele zoom for sports or landscapes, this combination works because many times in the field 1x magnification is not needed. b) The 300mm f/4L has 0.25x native magnification, good for a telephoto. Other lenses like Canon 200 f/2.8L, the 135mm f/2L, etc, have 0.15 to 0.20x magnification. Native magnification affects gain when TC and dioptor are added. The longer the focal length and greater the lens magnification, the more the subject magnification increases when using a dioptor. c) There is no light loss using Canon 500D +2 Diopter close-up filter, unlike using extension tubes. Focusing is easier. The 1.4x TC can be used or not, varying the magnification. Though you lose 1/stop with the TC, most Canon bodies will still auto focus at f/5.6. d) The 300mm f/4L IS is a wonderful lens for sports and larger wildlife. With the 1.4x TC you have a f/5.6 ‘almost’ bird lens. The only downside is if 300mm is too long for your non-macro uses, like youth soccer on a small field.

Close-up < life size. Macro is life size, 1:1 reproduction, 1x magnification or greater. There is loads of fun close-up photography at less than life size, 0.25x to 0.70x (butterfly and dragonfly hunting) you can do with extension tubes, close-up filters (diopters), or close focusing zoom lenses. A modest Canon 100mm-300mm zoom with a Canon 500D ($140) +2 diopter makes a good butterfly hunter, providing about 0.4-0.7x life size reproduction, depending on lens focal length and maximum magnification specification.

Depth of field vs. background blur. It is a struggle to obtain sufficient DoF under macro conditions. Focal length is less important than framing angle on the subject. The common opinion is, given lenses of similar optical design, the shorter the focal length, the greater the DoF; the longer the focal length, the more distance is compressed behind the plane of focus (less DoF). But this is too simplistic, and does not hold up under close focus distances with floating element macro lenses. http://www.vanwalree.c​om/optics/dof.htmlexternal link is very good amateur read on the subject. Navigate to sections where macro DoF is considered. Author makes the case a telephoto macro lens for many applications offers three advantages over its more symmetrical competitors of shorter focal length: an increased working distance, an increased depth of field, and a narrower field of view that comes with a more (absolutely) blurred and less obtrusive background.

Light loss. Camera lens f/stops are designed for infinity focus. As magnification increases (focus distances get closer and lens elements move away from sensor or film plane) the actual aperture (effective f/stop) becomes darker. The classic formula was about 2 f/stops light loss at close focus 1x reproduction. There is less loss, 1 1/3 stops, with Canon 180mm internal floating element lens.
The camera TTL meter automatically measures this light loss. We experience a darker viewfinder and f/stop-shutter speed challenges at macro magnification. E.g., A scene set at f/8 that a camera meters for 1/200 as a normal exposure with a regular lens, is metered as 1/50 with a macro at close focus. We experience it as slower shutter speed or lower f/stop macro challenges, requiring tripod and flash use.

A few among almost unlimited web sources of macro information
Tom Hicks 3-part macro for beginners with dioptors and extension tubes:
http://www.natureswild​scapes.com ...egory=gallery/zzzAr​ticlesexternal link
Steve Hoffman on macro flash, using Canon’s MP-E65mm lens, and other topics:
http://www.sphoto.com/​techinfo/phototech.htm​lexternal link
Lester Wareham of the UK has a good technical site on using Canon macro lenses, including the MP-E65:
http://www.zen20934.ze​n.co.uk ...raphy/Macro_Equipme​nt.htmexternal link
A section of Nikonian’s web on macro and close-up photography. Good explanation of reversing rings and bellows:
http://www.nikonians.o​rg ...ose-up_macro/macro_0.htmlexternal link
A sight that explains DoF alternatives under macro reproduction:
http://toothwalker.org​/optics/dof.htmlexternal link
Bob Atkins has many pieces of information on general and Canon macro lens magnification calculations:
http://www.bobatkins.c​om ...raphy/eosfaq/closeu​p2.htmexternal link
http://www.bobatkins.c​om ...graphy/eosfaq/close​up.htmexternal link
Phillip Greenspun macro introduction from “early days” of the web:
http://www.photo.net/l​earn/macro/external link
Explains diopter close-up filters, and also has other useful information:
http://www.rogercavana​gh.com ...ent/500d/500d_filte​r.htmlexternal link
Italian photographer has a good technical site on macro magnification, and a review of Nikon’s macro and non-macro lenses:
http://xoomer.virgilio​.it/ripolini/Close_up.​htmexternal link

Original thread with further discussion here

Post #2, Aug 27, 2005 23:11:19

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Why Are Constant Aperture Zooms made/preferable?

The reason that zooms with a constant aperture were designed is so that the exposure won't change when zooming.

Assume that you are using manual exposure mode with a lens such as a (mythical, for illustration) 24-70mm f4.0-f5.6. You set the shot up and meter the scene using the camera's meter with the lens zoomed to 24mm. The exposure settings you choose are 1/125 second shutter speed and f8. Now, you zoom to 70mm. Because this example lens has a 1 f-stop change because of zooming, you now are going to underexpose by a full f-stop because the light coming through the lens has dimmed by a stop. You would have to adjust either shutter speed or aperture to keep a proper exposure.

With zoom lenses having a constant aperture, you can set your exposure and forget it. Zoom away, touch up focus at each focal length, and shoot.

Hope this makes sense. It's why I have purchased only zooms with constant apertures. They are more expensive, but they will pay for themselves when the chips are down and I am working fast.

Post #3, Sep 14, 2005 06:59:16

Skip Douglas
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How Are Constant Aperture Zooms Made?

What actually changes is the apparent aperture, or the entry pupil of the lens. As the magnifying front element/group moves relative to the physical aperture at the diaphragm when you zoom, it, not surprisingly, magnifies the aperture as seen from the front of the lens (the "entry pupil"). Constant aperture lenses are designed so that, in addition to all the other corrections that are made to the lens, the entry pupil varies in direct 1:1 ratio with the focal length of the lens as you zoom.

Original thread here

Post #4, Sep 14, 2005 09:30:46 as a reply to SkipD's post 2 hours earlier.

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What are "drop in filters" ? How do the drop in filters differ from rear mounted Gel filters?

The long lenses come with a drop-in filter that is a clear glass. Something is required to fill the hole, and the clear glass is actually part of the optical formula.

The 17-40 and other such wide lenses do not actually use a drop-in filter, but rather a sheet of plastic (gel) that slides into a holder at the back end of the lens. They are not supplied with a filter.

Hope this helps.

Have Fun,

Post #5, Dec 31, 2005 21:25:11


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Canon makes two sizes of Drop in filters. Are they interchangeable?

To some extent .. yes and no.
Regarding Canon's long telephoto drop in filters,. just some additional info;

When Canon switched from there previous generation of long AF telephotos to the newer models that have Image Stabilization and weather sealing,. they changed the drop in filter holder,. and subsequent size of the glass filter required from 48mm to the current 52mm

I have lenses that require both types,. and it turns out that despite the differences,. there is some level interoperability.

For instance,. the 48mm drop in polarizer functions fine in the 500mm f/4L IS which is supposed to use 52mm drop ins.

Upon further investigation I found that despite the fact that the outer diameter of the glass filters installed differs .. the opening within the metal holders
for each of the clear glass "stock" units is an identical 40mm (yes 40mm... the extra 8mm or 12mm is the metal surround)

Also,. the distance to the center of the glass filter from the inner edge of the holders cap is the same,. ie: if the 48mm fits in the lens opening of a 52mm lens like the 500mm f/4L IS,. it not only just "fits" it fits in a way that the filter glass and that 40mm opening is placed exactly correctly .. it should not in any way impair the lens function or light gathering.

Now,. mind you the 52mm filters do not fit in the older lens,. well at least not into the 200mm f/1.8L that I have to experiment with.

I mention all this because this came as great news to me,. as I had invested a significant sum in the 48mm drop in filters for the 200mm prior to getting the 500mm. It was greatly comforting to be spared having to purchase these filters all over again.

The 52mm is of course weather sealed,. the 48mm is not.

Post #6, Jan 01, 2006 13:15:09 as a reply to CoolToolGuy's post 15 hours earlier.

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Shedding Light On Polarising Filters

*More Discussion in original thread Here*

Well after doing a lot of surfing and gleaning information from many helpful people on POTN, I think I can now give back this info in one thread. Hopefully this will reduce the confusion for the next person who tries to research this subject.

So, you've purchased an ultra wide angle lens for your DSLR and you would like to buy a polarizing filter for it? Unless you've been down this path before, the many brands and models are extremely confusing. The questions of whether or not to go with warming, Kaesseman, slim, circular, linear, graduated... etc etc just makes it worse.

The major thing that everyone seems to be in agreement with, is that you should buy a good quality filter. "Don't put a $10 piece of junk on your several hundred (or thousand) dollar lens." The brands that I have read through many forums and reviews which have been recommended include B+W, Hoya, Heliopan and Kenko. I'm sure there are many others, but they seem to be mentioned by lots of people as being quite reliable.

The other agreed points are that with auto focus in digital cameras, you need to get a circular polariser; the linear polarisers can interfere with the autofocus. Also a filter with "multicoating" is a good idea, as these can be more effective in preventing lens flare (coupled with your lens hood of course).

The first big issue with ultra wide angle lenses and polarisers (possibly other filters too, but I did not research them in any detail) is the possibility of vignetting. From my understanding, this is because the lens is so wide, it perceives the shadow of the edge of the filter. (I'm sure someone will correct me if I'm way off base.) This is where the first debate begins: how wide a lens can we use a polariser on before this problem begins to occur? ie: Which lenses cause this concern; 10-22mm... or maybe the 12-24 lenses? AND does having different lens factors (ie 5D full frame vs the Rebel's 1.6) have a further effect on this issue? I don't know the answer, as there were many theories out there. Hopefully someone will test this theory. (or they already have and I just couldn't find them!)

The next part of the debate is whether or not a "slim" filter design is required. These are filters that are lower in profile, thus creating less of a "lip" out from your lens- and hopefully less vignette. They are generally more expensive than their "regular" counterparts.

Many of the slim filters out there have no front thread, which means you cannot stack lenses (which is debatably not neccessary anyway... more about that later) and more frustratingly, (for me anyway) you can't attach your normal clip-on lens cap. All of the filters with the no-front-thread-design that I looked at, provided you with a plastic slip-on cap. Reportedly, they don't stay on very well (I remember my G2 had one and it was constantly falling off- but it also had a safety cord) and are easy to lose. Many people have spoken very favourably of these filters and were able to tolerate the lens cap issue. One possible solution, is to have a lens cap saving device attached- basically a little plastic "dot" that sticks to the lens cap and then is attached to the lens via elastic. I've got one on my kit lens; very cheap to buy.
http://www.amazon.com ...8612006?v=glance&n=​502394external link

Just to give a comparison here (all filters quoted in 77mm):
The B+W 77mm Circular Polarizer (MRC) Multi-Resistant Coating Glass Filter is $144.95 at B&H.
The B+W 77mm Circular Polarizer (MRC) Multi-Resistant Coating Glass Filter Slim is $164.95.

Another filter type that was thrown into my selection pile, just to create more confusion, was the Kaesemann. As per B+W's blurb: "Kaesemann ("encased") filters are completely edge-sealed for maximum durability under extreme climatic conditions." Some of the other filter manufacturers (Heliopan for example) also make Kaesemann versions of their filters. One of the generous people on here suggested to me that it was a bit of overkill purchasing this for normal landscape/travel photography and I agreed that the extra cost wasn't worth it to me. Others might find the extra protection useful. FYI:
The B+W 77mm Kaesemann Circular Polarizer Glass Filter is $164.95 at B&H; and
The B+W 77mm Kaesemann Circular Polarizer Glass Filter Slim is $174.95.

Two other options I was able to find, was the "Moose" filter. http://www.moosepeters​on.com/gear/moosefilte​r.htmlexternal link (also available on other vendors' sites) and the Hoya or Kenko Pro 1 filters.

The Moose filter (made by Hoya for a nature photographer) is a combined "warming" filter and polariser which has a front thread. The disadvantage is that if you don't want the warming effect, you can't separate it from the polariser. (For an explanation on "warming", check out the link above.) The other thing I could not find any literature on, was whether or not this filter is multicoated. If it is, then it could be a decent buy, because it "works on any lens up to 17mm and WILL NOT VIGNETTE regardless of which f/stop is used!" (quote from his site). Ah!- only 17mm. This filter still remains a bit of a mystery to me. The creator raves about it (as he would of course), but uses a Nikon D2X (1.5 crop factor) and lists the Nikon 12-24 as one of his lenses. Maybe he doesn't use his polariser below 17mm. Anyway, I wasn't able to find many reviews out there about his filters, but at $118.50 from B&H or $99 direct from his site, they're worth investigating further. As I had to make a decision tonight and make my purchase, I left it up to others to "run with the ball" if they're interested.

Now, onto the Hoya & Kenko Pro 1's...
These two are both slim filters, but they also have a front thread! condyk suggested the Kenko to me as he (and from many other resources out there online) believes that Kenko and Hoya are one and the same... and Kenko is cheaper. Unfortunately for those of us in the US of A, it seems that the Kenko Pro 1 is marketed here as "Hoya Pro 1" and marked up considerably. As far as I was able to figure out, the same filter is marketed in the UK, Hong Kong and Australia as "Kenko Pro 1". This info could be wrong, but all evidence I've been able to find points in this direction. FYI:
The Hoya 77mm Circular Polarizing Pro 1 Digital Multi-Coated Glass Filter is $194.95 at B&H.
I then found the Kenko on the link below for $108.95AU (approx $80USD):
http://cgi.ebay.com.au ...egoryZ15219QQcmdZVi​ewItemexternal link

Again, I cannot categorically say that these are the same filter, but if they are, then perhaps people with more time and patience than me could ship them over. Alternatively, if you live somewhere where the Kenko is available, lucky you! I read many favourable comments about the Hoya Pro 1, so taking everything above into account and unable to find someone who had actually tested the Tokina 12-24 with a normal sized polarising filter, I chose that one. FYI, I was able to get it from:
http://www.2filter.com​/hoya/hoya_pro1_digita​l.htmlexternal link for $156.86 (normally $194.63). One of the forums I was browsing through pointed out you need to actually click on "order" to reflect any discounts they might have at that moment.

I was able to find one person who tried a normal sized UV filter on his 12-24, and apparently didn't experience too much of a problem with vignetting.
http://www.fredmiranda​.com/forum/topic2/3253​96/0#2756574external link
Still not 100% convinced, I still bought the Pro 1. I would love to hear about peoples' actual experiences with any of the ultra wide angle lenses and these filters. The easiest thing of course, would be to walk into a shop and try this out, but none of the shops in my area stock anything!

One final note, I was really interested in ND graduated filters and started looking into those as a possibility. A pro pointed out to me that with digital, the only thing you can't duplicate in Photoshop (or similar software) is polarising. I found a fantastic tutorial for duplicating the ND graduated effect in Photoshop here:
http://www.fredmiranda​.com/article_2/external link I've been experimenting with it and it's fantastic! Many different effects, normally achieved through a filter (like warming for example) can be achieved through software- so save your dough for a good polariser!

Hopefully this dribble helps someone. I apologise if any of this is incorrect; I am by no means a professional and my intentions are only to prevent someone from going through the confusing headache I did. Maybe if there's anything to add or amend here, it could be made a "sticky" down the track; especially when some people have provided feedback of their own personal experiences. There are other variations on the examples of basic polarisers I mentioned and they can be much more expensive. I just focussed on the ones under $200 and went from there.

Thanks for reading and happy shooting! :)

*More Discussion in original thread Here*

Post #7, Jan 04, 2006 04:33:04

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Canon EF Image Stabilization.

There are five "versions" in Three "generations"

There are 1st generation IS lenses and second generation IS lenses, and the most recent are 3rd Gen;
(Including the 70-200mm f/4L IS, 200mm f/2L IS and 800mm f/5.6L IS) These are the ones that claim 4 stop IS.

Canon has made lenses with more than two types of IS functionality, which can be a source of confusion.
Do not however confuse IS functionality with "Generation" as in 1st and 2nd Generations there are multiple sets of "functionality"

In the first Gen there were lenses with mode 1 & 2 (ie: panning) 100-400mm and 300mm f/4L IS for example... as well as ones that did not have Mode 2. These were the first 75-300mm IS and the 28-135mm IS.
1st Gen IS lenses had to have the IS manually turned off when mounted on a tripod or solid arrangement, as the IS could introduce image anomalies and otherwise unwanted behavior if left on while tripod mounted.

At first, all second generation IS lenses have Mode 1 & 2, but recently some of the newer models at the wide ends also lack the Mode 2 function. In addition to faster start up times, and improvements that Canon claims add more "stops" to your hand-hold-ability, The current 2nd generation of IS only adds one set of features in addition to those already found in 1st gen multi mode IS. That feature is Tripod detection and tripod vibration mode. (I don't actually know the name of this,. so that's my own lame term. Canon states this "the IS mechanism automatically goes into a special mode which is designed to detect and correct for mirror slap and shutter movement at slow shutter speeds" )

The basic 2nd or 3rd generation IS will disable IS when it detects that the lens is mounted solidly such as on a tripod.

SuperTelephoto lenses with 2nd / 3rd Gen IS also detect tripod mounting. Rather than disable the IS, 2nd gen Superteles will use IS to counter subtle vibrations that are present and magnified by super teles even when on a tripod. This includes mirror slap vibration.

The 3rd Gen lenses added a new "IS Mode 3"

IS Mode 3 was announced with the EF300mm f/2.8L IS II USM and EF400mm f/2.8L IS II USM lenses, and is also in the EF500mm f/4L IS II USM and EF600mm f/4L IS II USM telephoto lenses. IS Mode 3 takes the benefits of standard IS (effective for both horizontal and vertical camera motion) but, instead of it being active all the time, it only activates when you fully press the shutter button to take an image. It is especially useful for sports photography where you are likely to be moving between subjects quickly.

Canon documentation:
Canon USA Image Stabilizer Basicsexternal link

Canon U K Image Stabilizer infoexternal link

Canon CPS Knowledge Bank Image Stabilizationexternal link

Some additional discussion;

Gain indicates the number of shutter speed steps you can expect to benefit from
Modes indicates whether there is a single mode (not good for panning) or an additional panning mode.
Tripod tells you whether or not the lens can sense the use of a tripod

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foxbat wrote:
Tripod image stabilization is only available on the following lenses:

300mm f/2.8L IS
400mm f/2.8L IS
500mm f/4L IS
600mm f/4L IS
28-300/3.5-5.6L IS
70-200/2.8L IS
70-300/4.5-5.6 DO IS
400/4 DO IS
70-200mm f/4L IS
200mm f/2L IS
800mm f/5.6L IS

If you don't have one of those then you must switch off IS on the tripod otherwise you should leave it on since the IS in these lenses knows how to compensate for mirror slap, wind movement and all the other little tremors that affect a very long lens.

Post #8, Jan 08, 2006 21:34:41

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One further note on the second-generation IS. At least with the 70-200, Canon still recommends that you turn off IS when using the lens on a tripod.

Post #9, Jan 09, 2006 10:21:46

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Light Fall Off or Dark Edges on photos.

Often dark edges around a photo is caused by "Light Fall Off"

Light fall off is often confusingly referred to as "Vignette"
In fact it seems common for the terms to be used interchangeably these days..
However doing so has created a lot of confusion as the two phenomena are caused by different things, behave differently, and are remedied differently too.

Vignette is caused by a physical object blocking the light path. The wrong hood, deep filters, and your hands can cause vignette.
It is fixed by removing the object blocking the angle of view of the lens.

Light falloff is inherent to and caused by the optic assembly of the lens itself..
Pretty much all lenses have a measurable degree of light fall off, but how perceptual it is varies significantly with differing lenses.

Light fall off is always at it's worst when shooting wide open.
Fixing it is done by simply stopping down the lens. How much one needs to stop down to make light fall off disappear also varies from lens to lens.
Like overall sharpness, or contrast, a measure of a lens' quality and usefulness in the wide open settings is how much (or little) light fall off the lens displays,. and how far one needs to stop down to eliminate it's visibility.

On some lenses,. light falloff is still noticeable wide open even on 1.6X crop cameras.
Obviously on a full frame it will be much more noticeable. How noticeable in any case often depends a lot on the nature of the shot.

Jon wrote:
The reason stopping down helps elimninate Cos^4 light falloff is because at smaller apertures, the incident light is coming from a smaller portionof the lens (less off-axis incoming light), so the angle at which the incoming light strikes the sensor is closer to normal.

The cos^4 law is essentially describing the decrease in light per unit area striking the sensor at the corners due to the greater distance light travels to reach them than it does to strike the center of the image area. There are a couple of other factors which come into play, but that's the most obvious one. So it's yet another result of the "inverse square" law that describes light fall-off as you get further away from the light source. In this case, the "source" is the rear nodal point of the lens.

Post #10, Mar 19, 2006 02:54:13

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Lens Testing and sharpness


In this link there is a PDF Document that both describes a good focus test as well as providing the necessary printable charts.
Due note that unlike many other "focus charts" this one provides a solid 3D object to focus on as opposed to an angled test sheet only.

Download Test Charts hereexternal link

HOW TO Perform a lens focus test

Following is a consolidation of posts in a thread called "Concerned About Lens Sharpness - Epiphany"....

Mr. Clean Wrote:

I think this is a must read for any newb.

First off - I sent in my Sigma 24-70 f2.8 EX DG Macro to Sigma to sort out it's front focusing problem wide open. I received it back, tested it and thought it was still front focusing. Called them and they were very very helpful and suggested that I send my camera in with the lens. That got me to thinking, if they're going to calibrate the lens to my camera, perhaps my camera is at fault?

Recently got a Sigma 10-20, every shot is a keeper unless I was just messing around or composure/exposure was off.

I received my Canon 85mm f1.8 yesterday and took it out shooting. Great shots, but the occasional shot was soft wide open, a lot were spectacular. Some of the soft shots were due to "iffy" lighting, some seemed front focused.

So I brought my camera with me today and did a ton of test shots with batteries and flat things with text etc. etc. etc. and here's what I found.

Wide open and far away, I think the XT performs horribly when trying to shoot things of various DOF and detail. For example, I shoot the infamous row of staggered batteries and it's front focused with both my 85mm and 24-70. BUT - if I get to the minimum focus distance, both are tack sharp wide open. But at the minimum focus distance, you usually have better contrast on the subject, and the subject fills more of the center AF point and thusly autofocusing better! If the batteries/focus chart are at a distance of 3 feet or more from your camera, I think you'll see front focusing.

Long story short - Don't immediately blame the lens, your camera may be the culprit and in my case, I believe the camera is the culprit. And then again, if you own a XT, my opinion is your camera is more than likely the culprit!

Which is too bad, I bought two new lenses lately, and part of me wishes I would have sold the XT and upgraded to the 30D...

Thoughts? Agree/Disagree? Or should this go to the Camera section?

Thanks so much to fstopjojo for helping me out! He has been just a huge help.

form wrote:

Oftentimes, because the subjects I'm attempting to focus on are rather small and against a fairly detailed background, I get back focus even if the focus point is on the foreground subject.

Tom W wrote:

Time for the famous focus point vs. actual focus sensor image:


Note that the actual sensors (in red) are a good deal larger than the indicators in the viewfinder. This particular image is from a 10D, though the trend continues with other non-1 series bodies.

The result is that the AF can be sensitive to any contrasty point covered by the sensor, even if it is outside of the indicator box in the viewfinder. I crudely overlaid the 10D AF diagram over a ruler scale to try to illustrate how the AF sensor might find its "target" somewhat away from the intended point if that intended point is small and surrounded by contrasty background that can grab focus.


gcogger wrote:

That may also explain why the 'battery test' can give misleading results if shot from too far away, or the batteries are too close together.

Mr. Clean wrote:

Exactly! And you couple that with a lesser AF system (when compared to the 20/30D and ID systems) of the XT I think the problem is even more apparent!

Tom W wrote:


At the risk of cluttering up the thread with images, here's an example of how to separate those batteries enough to be sure that only the intended target will be picked up by the AF sensor:


dmstraton wrote:

Wow, great information in those diagrams. I experienced similar issues with my XT, and they virtually disappeared when I upgraded to the 20D...now I know I wasn't crazy...I never thought my lenses were an issue, I knew it was the camera because it seemed hit or miss...but looking at the above is illuminating...I still loved the XT though.

Dellboy wrote:

Good post Tom W very enlightening. Without wishing to highjack this thread a have a question about simlar focusing problems.
I hear alot about front/back focusing lenses. How can it be the lens(es) problem when its the camera that decides when the lens is in focus?
I have always assumed that the focus issues are the cameras problem or a users problems by using a focus recompose technic coupled with a large apperture and a close focus distance.
Do you think lens front/back focus problems are a myth?

Thanks in advance, Dellboy.

Lester Wareham wrote:

Nice one Tom, that does a good visual explanation of this issue - I think the moderators should sticky that.
And if people want to focus test this link:
http://www.canon-dslr.com .../Canon_SLR_Focus_Te​st.htmexternal link
is probable a better target.

Mr. Clean wrote:

I respectfully disagree, simply because if the camera and chart aren't set up properly it will throw the test off. If you lens front or back focuses, a battery test should be suffcient.

Additionally, this comment on the aforementioned link speaks volumes:

Note the 50mm f1.4 test shown, will give some shots in focus (as well as some front and some back focussed). This causes people to think the camera is ok and they are the problem - when one shot looks sharp and the next looks blurred. In fact it's just the level of tolerance of the camera system, in that the autofocus varience per shot, is so great - and clearly looking at these images not suitable for the job.

Tom W wrote:

While there is some tolerance in the AF system of any camera, carefully controlled tests using a tripod, stationary subject, mirror lockup, remote shutter release, and good lighting indicate, at least in my experience, that there's often more tolerance in the user than in the camera system. I recently acquired a used 30D and found several images that I thought were a bit soft. Performing a quick focus test with a tripod quickly told me that I was the problem and not the equipment.

The fact is that I was shooting indoors with a relatively slow shutter, but wasn't keeping myself steady enough. Images viewed at 100% are good at revealing imperfections including many that won't show up in a print. In my case, I suffered both from a bit of motion blur in some shots and from my movement exceeding the shallow depth-of-field of the 50 mm f/1.4 lens in others. When locked down in the tripod to remove the "human" element, the camera performed well.

That's not to say that the equipment cannot be wrong or out of tolerance. It certainly can be. Testing goes a long way towards proving that the gear is good or not-so-good.

4x4rock wrote:

I'm tempted to borrow my friend's 1DMK2 and test with my lenses see if there's a difference.

Hmmm...he has 2 of those MK2, maybe he can sell me one for cheap

fstopJojo wrote:

Be prepared to be blown away.

4x4rock wrote:

Joe, that was what I'm afraid. I can't upgrade now...

Lester Wareham wrote:

Originally Posted by Mr. Clean:
I respectfully disagree, simply because if the camera and chart aren't set up properly it will throw the test off. If you lens front or back focuses, a battery test should be suffcient.

Thanks for your comment Mr Clean - this is not my target but one that is a lot more sensible than many suggested.

Well any test will be poor if it is not setup correctly, I am not sure what your exact issues are here but it might be better to take them up with test target designer.

I suggest this target rather than the flat one often quoted on this forum, as at least the focus target is parrallel with the sensor rather than at 45 degrees.

My problem with the battery test is, batteries are curved normally and so even if they cover the whole of the AF sensor area as shown in Tom's visuals, they are at different depth of field. A similar test with flat object like PP3 batteries or remote controls is proably OK but less informative.

Originally Posted by Mr. Clean:
Additionally, this comment on the aforementioned link speaks volumes:
Note the 50mm f1.4 test shown, will give some shots in focus (as well as some front and some back focussed). This causes people to think the camera is ok and they are the problem - when one shot looks sharp and the next looks blurred. In fact it's just the level of tolerance of the camera system, in that the autofocus varience per shot, is so great - and clearly looking at these images not suitable for the job.

Yes this is just a reference to Canon's AF specification that it is in tollerence if the lens AF within the DOF. I don't know if this is some particular lens he was having trouble with but reading through the examples he seems to be suggesting the 20D body was problematic and this was an example of it. If you go to the web route it seems he has been having a big ding-dong with Canon about their AF calibration method.

For info I don't use any of these tests myself but use ISO slanted tagets and test software based on that standard so I see exactly how sharp the lens is. I do 3 focus runs so I can see the difference in resolution on each run in lp/mm. It is not normally much in indoor daylight (not incredibly bright), the shorter and slower the lens the more variation there will be. The amount of variation is not normally visible, I found this to be the case with my 50mm and all my lenses.

When you get lots of AF variation it probably means you have too little light, a low contrast subject, too small a AF subject, a AF subject with significant depth extent or equipment problems.

Tom W wrote:

Originally posted by Lester Wareham:
My problem with the battery test is, batteries are curved normally and so even if they cover the whole of the AF sensor area as shown in Tom's visuals, they are at different depth of field. A similar test with flat object like PP3 batteries or remote controls is proably OK but less informative.

While there is some expected tolerance within the depth-of-field (or 1/3 of DOF in some camera/lens combinations), the camera generally does well with finding the front-most spot on even a curved surface like a battery:


Still, your thought that a flat surface should be used is not wrong. That way, there's no doubt as to what the camera is supposed to focus on when the focus sensor is centered over a flat, perpendicular surface such as in the test chart that you've linked to or a square battery as you've mentioned.

narlus wrote:

now i've got this great thread to show my wife as a rationale for body upgrade.

Mr. Clean wrote:

Good luck - It didn't work for me last night

Post #11, Aug 27, 2006 14:38:57

5D III, 70D, & various lenses

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What is "The Holy Trinity"

A term originally coined By POTN member Schmoelzel, The Holy Trinity is a collection of three of Canon's finest black L series Prime Lenses.

EF 35mm f/1.4L
EF 85mm f/1.2L
EF 135mm f/2L

Inclusion in this select group is based on nearly legendary image quality in the right hands.

Original thread here

Post #12, Sep 22, 2006 13:06:50

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What are "The Four Riders Of the Apocalypse"

In keeping with the "Holy Trinity" tradition, the Four Riders of the Apocalypse was coined by Yours truly to describe Canon's less subtle range of sledge hammer big white beast L lenses.

The Official Four are;
EF 200mm f/1.8L ( now replaced by 200mm f/2L IS )
EF 300mm f/2.8L
EF 400mm f/2.8L
EF 600mm f/4L -or- EF 500mm f/4L

However, like the Horsemen in the DiskWorld series by Terry Pratchett, there are alternates,. PESTILENCE which was wiped out with the invention of penicillin can be substituted with POLLUTION, another L horsemen the equally impressive, and interchangeable with the EF 600mm f/4L for making up the complete set of four;

EF 500mm f/4L

And the fifth Horseman CHAOS (who left before the group got really famous),.

SIGMA 300-800mm f/5.6 EX HSM
... Now represented by the EF 800mm f/5.6L

Original Thread

Post #13, Sep 22, 2006 13:18:25

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Canon 70-300mm DO IS - Getting best images from a controversial lens.

Canon's 70-300mm f/4.5-5.6 DO IS lens will always remain a controversial lens. The 70-300 DO is a high quality lens, with extremely fast focus speed (rear element USM), with FT-M, a non rotating front element, outstanding mode 1 and 2 IS, absence of chromatic aberrations, that takes good pictures, and then suddenly -BAM- frustrates users at critical moments in difficult lighting.
I thought POTN members might benefit from a thread where members share their experiences extracting the MAXIMUM image quality from the 70-300 DO IS, not bashing it.

Xavier (Fovea) has an excellent 70-300 DO IS handling tips web page: http://www.fovegraphy.​com/70_300DO_TipsE.phpexternal link
Luminous-Landscape's M.R. uses it effectively getting strong travel images: http://www.luminous-landscape.com ...nses/Canon-70-300mm.shtmlexternal link. His best tip is at the end, in regarding adopting PK Sharpener.
I have used the 70-300 DO IS enough to put experiences in the captions of 13 images: http://aesop.rutgers.e​du ...-300_DO_IS_Lens/index.h​tmexternal link

I have the luck to use the 70-300 DO IS for its strength, and L zooms for their intended use. 70-300 DO IS experience leads me to use it with an integrated workflow to extract the maximum potential from images:

1. DO images respond best to RAW capture and post processing. This is not a lens for JPEG shooters. RAW capture is the only way to use this lens if you follow Xavier's tips. Being able to set black point, WB, etc., makes a world of difference. I have rendered decent 70-300 DO images under hazy days with bad veiling flare lighting: http://aesop.rutgers.e​du .../slides/CropDusting​09.htmexternal link by using Canon's "Clear" Picture Style.

2. DO shooters should carry a Whi-Bal or similar WB card and shoot the card in the same light as their photos. Upon opening the RAW, using “Click WB” in any RAW converter makes a HUGE difference in DO image quality. DO images sometimes have a cooler flatter blue WB, low in the blue-yellow color axis, that takes WB correction on RAW conversion well. It's as if the camera misses AWB with the DO lens connected. Images beauty right up to natural color with a RAW one click-WB. I use a Whi-Bal for most digital photography, to get the WB right in adverse FL, incandescent, and vapor discharge lighting in gyms, but is essential with the DO, not an option.

3. DO users must learn “Edge Contrast Enhancement” sharpening in PhotoShop, or, as I did, buy a PS plug-in automating “Edge Sharpening.” The most important $99 I spent on digital workflow in 2004 was PhotoKit Sharpener. Virtually all my digital RAW captures and film scans go through PhotoKit Sharpener. There are equal competitors like FocalBlade or NiK. But, the DO lens and PhotoKit Sharpener BELONG together. PhotoKit has taken sharpening "off the table" as a time consuming technical workflow limitation. DO captures have resolution; and processed from RAW they need, benefit from, and tolerate specific sharpening to raise the accutance without resulting in sharpening artifacts.

4. Do not point the DO lens at foreground subjects where the OOF blurred background contains lots of fine repeating details, especially fine details with specular highlights. E.g., photographing a set of railroad tracks diminishing to infinity focus on a hot day. Instead of the rails smoothly OOF blurring, you get "chunks" of rail. Or a chain link fence behind an in-focus subject gives onion ring specular highlight bokeh. This lens resolves beautiful sharp images when fine details are the in-focus foreground. Many reviewers define this lens phenomenon as a “flare" problem, reducing the blackpoint contrast. I do not know what it is, but I find I it is limited to when the fine detail highlights are in the out-of-focus background. I use this lens to it's strengths. To modify a Clint Eastwood phrase, "A lens has got to know its limitations."

5. The DO performs best with no UV/protection filter over the front element. Take it off and use the hood at all times. This means some of the discreetness is lost.
6. Because the DO front lens element is heavy, the barrel will creep and the zoom ring is slightly stiff. It does have an anti-creep lock, locking the lens in the 70mm position. Walking about, ready to lift the lens, crop with the zoom, and grab a shot, the lens will extend to its 300mm extension. The zoom extension is mildly irritating, particularly at sport events, or street shooting. It takes getting used to if you are also an 70-200L shooter using internal focus and internal zooms
7. The DO, like all IS lenses, needs a 1/2 second half-press to activate the IS before shutter release.
8. The DO, like all tele zooms benefits from being used stopped down even 2/3 or 1/3 stop from its widest aperture. It is useable at f/5.6, nice at f/6.3 or f/7.1, and peaks out at f/8 +/-.

A Decision Tree.
Users need to think about the 70-300 DO IS differently. Understand the DO IS makes specific compromises as a professional level 70-300 mm travel zoom with a compact mass.

1. If you do not like digital darkroom post processing or shooting RAW capture, do not buy this lens.
2. If you need a lens MOSTLY for sport events, do not buy this lens.
3. If you do not need FAST USM focus like an L lens, but just need IS and compactness, save money and get the consumer Canon 70-300 mm IS. The 70-300 DO IS focus is faster, with FT-M, and superior ruggedness than the consumer 70-300 IS Canon with its micro-USM. The image quality of the consumer lens is good.
4. If you do not need a pocket portable discreet black lens, but value portability and impeccable image quality, consider the new 70-200 f/4L IS. With a 1.4x TC you will have 280 mm focal length at f/5.6.
5. If you do not need a zoom, do not need discretion, mostly using at 300mm, but need IS for hand-holding, and value impeccable images, get the 300mm f/4L IS.
6. If you do not need IS, do not need 300 mm, but need a discreet portable zoom, consider the Sigma 50-150 f/2.8 lens for travel or street photography.
7. If you do not need IS, but need a black, fast maximum aperture lens, consider the Canon 200 mm F/2.8L or the Sigma 70-200 f/2.8.

If you want/need some compromise of the above, the DO is a lens to providing it. For portable, discreet, rugged street photography, with IS, there is not too much competition.


Post #14, Oct 05, 2006 15:34:12

Wilt is an old fart who has extensive experience with many brands and many formats of cameras, and extensive lighting knowledge of both studio lighting and speedlights
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Focal Length and Frame/Sensor format on a DSLR

How Does Frame/Sensor size or "format" effect focal length choice?

Many times I see threads about 'what focal length' and both the question and the reply are couched in non-specifics about the frame size for which the comment is made. Remember, FRAME SIZE DICTATES the context in which a given focal length will behave. To borrow from another thread this point: 28mm is not 'wide' when it is used on a APS-C format dSLR like 350 or 30D

'Normal' is typically defined by the diagonal measure of the film frame. A 'true normal' for 35mm film (or 5D and 1DsII) is 43mm! But the industry has long settled on the convention that 50mm (or thereabouts) is 'normal' for that size frame. On that frame, 35mm is kind of 'in between'...semi normal and semi wide angle. 28mm is generally considered a true 'wide' , and 24mm is 'very wide' and 20mm is 'super wide'. At the longish end of things, 70mm-100mm are 'short tele' and '135-200' are 'tele' and 300mm and longer are 'long tele' and 'super tele' by convention.

In the world of portraiture, the shooting distance from the subject defines the facial perspective that we generally find most pleasing and 'realistic'. The focal length for a given shooting distance defines the 'framing' of the person and how fully they fill the frame area. Convention has found that about
70-90mm is good for waist-up portraits,
90-110mm is good for head and shoulder portraits, and
120-150 is good for headshots (a modelling and acting type of shot for sending out to casting people). Of course, different photographers will tell you that THEY do not follow these conventions, but it is generally true that most professionals and amateurs in past decades with 35mm film have found these ranges to be valid ones -- until you discover your own style and preferences!

Reminder: All of the above statements are in the context of 35mm film cameras. For APS-C dSLR, divide the above by 1.6 in order to find the equivent for your camera. So 28-30mm would fall smack into the 'normal' range, 17mm is a 'wide' but is not 'very wide'. You need a 15mm to get into 'very wide' and a 12mm to get into 'super wide'.

So for portraiture for APS-C format camera, the numbers mentioned two paragraphs ago would translate to:
about 50-60mm is good for waist-up portraits,
60-70mm is good for head and shoulder portraits, and
80-90 is good for headshots (a modelling and acting type of shot for sending out to casting people).

So the next time YOU 'recommend' a particular focal length, it is important to state the frame of reference that YOU are making the statement in (APS-C or FF, for example) and also to take into consideration the camera that might be listed in the OP signature line. And equally important, if you are the OP member, tell us which camera you are asking about! With the advent of FF digital, and with novices having the financial ability to 'buy the best' regardless of their level of skill, we cannot assume APS-C format is what they are referring to, either!

Post #15, Oct 15, 2006 11:43:55

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