Do I get a 50/1.4 or 35/1.4 for 20D natural perspective

[SR071]

Hi All,

Just looking for a bit of input on lens choice for the 20D.

Starting with the premise that a 50mm is going to give a natural field of view, very similar to what our eye sees:

I want to retain that natural field of view to my photos on a 20D - so do I go for a 50mm or a 35mm?

I've read all about crop factors etc. but nothing seems to answer this one properly.

It appears that to get field of view of a 50, I need 35 on a 20D - then when I eventually get a full frame camera, I will need to get a 50 to get the same effect.

Does all this make sense???

Yours in Confusion,

[KevC]

It appears that to get field of view of a 50, I need 35 on a 20D - then when I eventually get a full frame camera, I will need to get a 50 to get the same effect.


You're right! 35x1.6 gives you about 55 or something like that. You'd want that for the 20D, it'll give you the 50ish perspective that our eyes see.

The 35/1.4L is quite the awesome lens, it has quite the awesome price too hahaha. HIGH. There's also the 35/2 which is quite good for the fraction of the price.

You'd also want the 50/1.4 for the 80ish portrait length (if you do, indeed, shoot people). The 50s are the "easiest to make" therefore sharpest and etc. You'd wanna keep that one too!

[LightRules]

The Sigma 30 f1.4 EX is right up your alley: 48mm eFOV on your 20D. And the thing is "tack sharp" (at least in the center).

[grego]

If you can afford it and find it, the 35mm f/1.4 is a gem.

[craigsinclair]

The formula to find the natural perspective focal legnth of a format is;
X^2+X^2 = z^2
The 20D's format is 22.5mm X 15mm. Therefore the focal legnth needed for natural perspective is 27.041634565979919698394159506029mm.

I guess a 28mm lens would be close enough.

[SR071]

What's the 29th decimal place for that? I just want to be sure that rounding up doesn't make it equal to a 50mm.

*grin*


Thanks for setting me straight - now it's time to seperate money from wallet. grrrr

[Tom Camilleri]

The Sigma 30 f1.4 EX is right up your alley: 48mm eFOV on your 20D. And the thing is "tack sharp" (at least in the center).


Do you think the Sigma 30 f1.4 is better than the Canon 35 f2? Are the Canon 28 f1.8 and 24 f2.8 worth considering? I'm looking for a fast, "normal" prime for my 300D.

[grego]

Do you think the Sigma 30 f1.4 is better than the Canon 35 f2?

The Canon is cheaper, and it shows in the tests, because the Sigma outdoes the 35.

[Aschlaman@comcast.net]

I was shooting with my 5D and my 50 f1.4, 35 f1.4 and the 135 f 2.0. It was just like shooting a film camera, except that the viewfinder is dimmer. Nice camera. Like some others have said go for the 35mm f 1.4L. This is my favorite lens. Super sharp and contrasty. You'll love it too.

Art Schlaman
Canon 20D ,EOS-5D, 35mm f 1.4L, 50mm F1.4. 85mm F1.8,85mm f1.2L, 135mm f2.0L 18-85mm IS, 17-40MM f4L, 135mm soft focus, 100mm Macro
300mm IS F4L, 70-200MM f2.8L IS, 100-400mm IS L, 75-300mm IS,
Tamron 28mm-75mm f 2.8, Tamron 180mm f2.8 macro, 580 EX flash, EOS3
Canon G6, EOS3
Hasselblad Xpan w/ 30mm and 45mm
Contax G2, w/35-70mm, 21mm, 28mm, 35mm, 45mm, 90mm
Contax Aria, 21mm, 25mm, 28mm, 35mm, 50mm, 85mm
Fuji GA645i, GA670III
Epson RD-1 with Zeiss ZM 35mm f 2 and lots of Leica's
Epson P2000 storage device

[SkipD]

Hi All,

Just looking for a bit of input on lens choice for the 20D.

Starting with the premise that a 50mm is going to give a natural field of view, very similar to what our eye sees:

I want to retain that natural field of view to my photos on a 20D - so do I go for a 50mm or a 35mm?

I've read all about crop factors etc. but nothing seems to answer this one properly.

It appears that to get field of view of a 50, I need 35 on a 20D - then when I eventually get a full frame camera, I will need to get a 50 to get the same effect.

Does all this make sense???For the specific question of what focal length constitutes a "normal" lens for the 20D, it's approximately a 31mm lens if one considers that the 50mm is the "normal" lens for a 35mm film (or full-frame digital) camera.

However, I will guarantee you that a "normal" lens will quite frequently give you an image that isn't what you "saw" when looking at the subject. That's because the brain often processes an image and produces something in your head that is definitely not what comes out in the photograph. For example, you can view a hummingbird at ten feet and see a lot of detail because you have "tunnel vision" and concentrate on the bird. However, the camera with a "normal" lens on it - at that distance - will have the bird as just a very tiny portion of the image. The image is VERY different from what you visualized. Thus, you may need a selection of focal lengths to work with to produce the desired images.

Please read this thread thoroughly and you may get a better understanding of what I am talking about: http://photography-on-the.net/forum/showthread.php?t=94147

Your analysis of the difference between lenses on the 20D vs a "full-frame" body is correct.

[rdenney]

I want to retain that natural field of view to my photos on a 20D - so do I go for a 50mm or a 35mm?


The "normal" focal length is defined as the diameter of the frame. That word "define" is important, because it is a model for unaided vision, not a duplicate of it. We have agreed to define normal that way.

Mathematically, if the focal length is the diameter of the frame, the field of view will be 53 degrees, no matter what the size of the frame. The lens that achieves this with a 24x36 frame (i.e., full frame 35mm) is 43mm. So, the 50 and 55mm lenses that have always been sold as "normal" lenses are actually a touch longer than normal.

So, if you want that effect, you need a lens that is a touch longer than normal with the 15x23 format. The diameter of the 20D frame is 28mm, and the same touch longer than that is about 33mm. 35 would be close enough.

I suspect you would not notice the difference if it was a 28 or a 30. All the lenses in this range will give you that "natural" field of view.

In larger formats, "normal" lenses are usually made closer to the actual diameter of the frame than has been traditional in 35mm photography. I can only think of a few 35mm cameras that have 40 or 45mm lenses as normal lenses, but the equivalent 75 in 6x4.5 is standard. The differences aren't big enough to matter.

For me when using full-frame 35mm, a 35 seems as close to normal as a 50, and often I prefer the slightly wider lens. Thus, I might lean to a 24 as a normal lens for the APS-C format to get the same effect. The 24mm 1.4L is also available, heh, heh. It's no cheaper than the 35/1.4.

Rick "who relates everything to normal for a given format, instead of using equivalence multipliers" Denney

[craigsinclair]

I don't, as a general rule, recommend using 3rd party lenses. Now with that aside, Canon's 28mm f/1.8 is not so bad if stopped down a step or two and used as the pros use a lens-no "protective" filter and the hood in place. If one feels comfortable using a 3rd party lens; B&H has what looks like a nice used Sigma 30mm f/1.4 for sale at an attractive price. http://www.bhphotovideo.com/bnh/controller/home?O=productList&A=buyUsed&Q=381615

[DocFrankenstein]

Duuude you have it all wrong again.

To get the same perspective as "your eye sees", just put the camera to your face and take a picture.

Doesn't matter if you have a 10mm or 200mm lens on your camera. The perspective will be the same.

[CoolToolGuy]

The formula to find the natural perspective focal legnth of a format is;
X^2+X^2 = z^2
The 20D's format is 22.5mm X 15mm. Therefore the focal legnth needed for natural perspective is 27.041634565979919698394159506029mm.

I guess a 28mm lens would be close enough.

I don't know about the formula (could be right or wrong), but this is why Canon makes a 28mm f1.8 lens.

50mm was a convenient choice back in the day. For 35mm film, the actual 'normal' length is somewhere around 45mm.

Have Fun,

[Joe R]

rdenney nailed your answer. I personally prefer the 35mm FOV, which would be either a 24mm (38mm equivalent) or 20/21mm (32/33mm equivalent) lens on a 1.6x camera.

[SeanH]

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=162614&is=USA&addedTroughType=categoryNavigation

Nuff said............IN STOCK!!!!......do it!!!

[Lord_Malone]

Hi All,

Just looking for a bit of input on lens choice for the 20D.

Starting with the premise that a 50mm is going to give a natural field of view, very similar to what our eye sees:

I want to retain that natural field of view to my photos on a 20D - so do I go for a 50mm or a 35mm?

I've read all about crop factors etc. but nothing seems to answer this one properly.

It appears that to get field of view of a 50, I need 35 on a 20D - then when I eventually get a full frame camera, I will need to get a 50 to get the same effect.

Does all this make sense???

Yours in Confusion,

You answered your own question. On the 20D the 35mm is really a 56mm, which is what you want. A 28mm will get you closer at 45mm. If you go FF, get a 50mm.

EDIT:Oops. I'm all late. Didn't bother to read all the responses.

[craigsinclair]

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=162614&is=USA&addedTroughType=categoryNavigation

Nuff said............IN STOCK!!!!......do it!!!

Wish I could.

[rdenney]

Duuude you have it all wrong again.

To get the same perspective as "your eye sees", just put the camera to your face and take a picture.

Doesn't matter if you have a 10mm or 200mm lens on your camera. The perspective will be the same.

Duuuuuuuuuuuude, he said "field of view" not "perspective". He had it right.

Rick "twisting Doc's tail" Denney

[DocFrankenstein]

Your eyes have a field of view of about 180 degrees of visibility, where you see motion and can turn your attention to if need be.

Your FOV shrinks if you try to read a distant sign, or sitting on a date with an attractive person. Can be as narrow as 150-200 mm

Generally, wider lenses approzimate the eye better... especially for big prints. It allows the eye to grasp the whole picture AND concentrate on specific areas if need be.

[DocFrankenstein]

Point taken about the POV, yet the title of the thread is "natural perspective"

[Sean-Mcr]

For the last 6 months the 50 1.4 was the lens that stayed on my 20D 90% of the time. It was the closest i had to a "normal" lens. I've had the 35 1,4 for only a week now and i know already that it will be the lens i'll use most from now on. I'm thankful for the FOV with this lens on my 20D as i have what is in my opinion the finest 50 mm (ish) lens there is. I love this article on the focal length of 50mm/normal lenses
http://194.100.88.243/petteri/pont/Photography_lessons/j_Lesson_9/a_The_Faithful_50.html

I do look at things now and see if my own FOV (in focus) matches that of my 35 on the 20D. It's a fine lens that i love already, as i do the 50.14 which is why i have both. If you can't afford the 35 1.4 then get the F2 and the 50 1.4

[rdenney]

Your eyes have a field of view of about 180 degrees of visibility, where you see motion and can turn your attention to if need be.

Your FOV shrinks if you try to read a distant sign, or sitting on a date with an attractive person. Can be as narrow as 150-200 mm

Generally, wider lenses approzimate the eye better... especially for big prints. It allows the eye to grasp the whole picture AND concentrate on specific areas if need be.

Actually, I don't agree. Your eyes have a wide field of view if you include peripheral vision, but most people will only see details in a central cone, and fine detail on a line.

But photographs are not projections in air. They are two-dimensional prints. If you made the image with a wide angle lens that has a 120-degree field of view, you have to view the print from a close enough distance such that the frame of the print subtends a 120-degree angle with your eye. If you do, the image will appear to be normal, but you will only be able to dee detail in the middle of it. People don't look at photographs that way. They back up so they can take in the sweep of the image. If the image is wide angle, they will be faced with a perspective distortion--the position of the camera with respect to the subject is not the same as the viewer. That's why pictures with lenses much shorter than normal look like wide-angle pictures.

There is also rectilinear distortion, which causes round objects to be distorted in the corners of rectilinear images. The eye does not see a rectlinear world, but the brain is highly skilled at making those perspective corrections. A photograph that is outside that perspective expectation of the brain appears distorted, and rectilinear projection can be startlingly unnatural. That's why fisheye lenses are actually more realistic for some subjects.

Prints made from normal lenses can be looked at at normal viewing distance and appear to be natural because they don't require any perspective conversion by the brain. You don't get the peripheral subject matter, so it's like looking at a subject through a window frame. If you got close enough for the print to fill the peripheral vision, it would appear to have been taken with a telephoto lens. That's why normal lenses got defined as normal lenses--they encompass the field of view where people can discern detail, which is where they park themselves when looking at a print. So "natural perspective" means the relationship of the viewer to the print as much as the relationship of the camera to the subject--both of them must be approximately the same.

Rick "who uses extreme wide angle to startle the viewer into seeing things in a new way by forcing a significant perspective conversion when viewed normally" Denney

[DocFrankenstein]

I agree with everything, except this part:
If you do, the image will appear to be normal, but you will only be able to dee detail in the middle of it.
I've hanged a 20 by 24 print in a 3 foot corridor taken with a 28mm lens on full frame. I've observed the viewers' as they back up against the wall, placing themselves at about 2.5 feet from the print.

"wow, it looks so natural"

I beleive that the ultimate focal length that approximates human vision is the 14mm. The problem is that if the viewer 1 foot away from the print, the print would have to be 2 by 3 feet to maintain natural perspective.

Obviously few people have the resources to do that. The more probable possibility is that I'm just wrong and there's no reason to do it. ;)

[Jon]

I've hanged a 20 by 24 print in a 3 foot corridor taken with a 28mm lens on full frame. I've observed the viewers' as they back up against the wall, placing themselves at about 2.5 feet from the print.

"wow, it looks so natural"


Is that 20x24 inches, feet, or cm?
"Natural" should not be confused with "normal". Rick's 100% correct; to see a picture as the camera did, your viewing distance should be proportional to the original camera-subject distance as modified by the degree of enlargement. However that's not how we view pictures, hence "wide angle distortion". "Natural" may merely imply that you avoided (through careful composition, no doubt) the characteristic "wide angle" look.

[DocFrankenstein]

20*24 inches