F-stop

[Woodman7]

I took a lot of pictures this weekend. Many of them were landscapes. I was shooting in P mode and many of the pictures were taken in lower apetures sometimes 2.8. Many of those pictures would have been so much nicer had I used higher F-stop. Is there some sort of a rule out there to help you decide how much depth of field to use. I tried some shots with a high F-stop but they slowed the shutter speed down so much I couldnt hand hold. Thanks for the help. What f-stop do point and shoot cameras use?

[Yavor75]

WoodDude-
Th reason you won't get many responses to this is because what you need is a lesson on Depth of Field.
It is the most basic of concepts in photography.
I can see that you know that higher f-stops result in better overall focus, but you need to have a tight grok on how the whole thing works. Search google for a good description.(and read the 10D manual 3x times!)
The 10D will tend to go for lower F stops in P mode- to insure you don't get motion blur from hand-holding the camera. Go into A Priority mode and push that rotory wheel until you see F5.6 or better. Anything over F11 is useless on the 10D...F8 being the sweet spot.
Many times, you won't be able to achieve 1/125th shutter speed- and so will be risking motion blur.
The 10D has very low noise at 400asa, so adjust the ISO for 400ASA in anything less than good light.
In fact, 200ASA is virtually the same as 100ASA with the 10D (noise-wise).
The traditional relationships between f-stop /asa/noise (grain), DOF..etc. are a bit different when using the 10D- but the basic guidelines still apply. Read this group to learn more about these things.

Have fun!
Bob

[Belmondo]

This is a good explanation, although a little technical. Check it out.

http://www.uscoles.com/fstop.htm

[robertwgross]

What kind of camera are you trying to shoot?

---Bob Gross---

[Vegas Poboy]

Go by your local bookstore & pick up a copy of Kodaks guide to 35 mm Photography. It's a general all around book on photography. Depth of field is very important & thats what your missing.

[daveh]

woodman7 wrote:
Many of those pictures would have been so much nicer had I used higher F-stop. Is there some sort of a rule out there to help you decide how much depth of field to use.

That's an artistic/personal question - which you seem to have answered in the immediately preceding sentence. The camera will only make technical decisions - and only if you let it.

woodman7 wrote:
I tried some shots with a high F-stop but they slowed the shutter speed down so much I couldnt hand hold.


Consider a tripod. (Or, in a pinch, a fence post, car hood, rock, tree stump, or higher sensitivity/ISO.)

woodman7 wrote:
Thanks for the help. What f-stop do point and shoot cameras use?

Most are variable though the lenses on many are small and won't open further than f4 or so.

[Andy_T]

Yavor75 wrote:
Go into A Priority mode and push that rotory wheel until you see F5.6 or better. Anything over F11 is useless on the 10D...F8 being the sweet spot.

Bob

??? Wouldn't that depend on the lens you're using ? ???

Regards,
Andy

[RichardtheSane]

Anything over F11 is useless on the 10D...F8 being the sweet spot
I had just copied the same piece of text to point that out. :) The camera has nothing to do with the 'sweet spot' as that is all about the optics. Also the 'sweet spot' tends to refer to a paticular focal distance/aperture combination.

F8-11 are considered to be good 'whatever' apertures because it will give good sharpness without sacrificing shutter speed. I said 'whatever' apertures, and I meant it - it is ideal for those occasions when you can't decide what aperture you want, or you are shooting something that requires no depth of field but good sharpness.

I disagree completely with the statement about not needing to go higher than F8/11 on the 10D, especially for landscapes.The majority of my landscape shots are done at F11-F22 so that I can get the foreground sharp as well as the background. Try getting the forground as sharp as the shot below with F8 (Shot at F22 @ 19mm :) )
http://www.richardlindley.co.uk/gallery/show.php?p=&id=35&gallery=landscape

[Woodman7]

Thanks for the information guys. I didn't add alot of information because I wasnt completely sure how to ask the question. I am new to photography, therefore the basic question. I have had the 10D for a few months and have done mostly shots of people doing various activities. I started using the 28-135 IS lense. I did some landscape shots of the mountains because I live in colorado but like I said mostly people. With that lense I was always shooting at 3.5 or above. I bought two new lenses last week the 24-80 2.8L and the 70-200 2.8L. This weekend I went to Gettysburg and to Valley Forge and wanted to take some great pictures. I noticed that because I didnt know what I was doing many of shots didnt turn out the way I would have liked. I shot in P mode and many of the shots do not show the Depth of field of the valleys or Fields. Because I bought such nice lenses I was using lower apertures that I was not used to (2.8). I had in the back of my mind Higher F-stop means better sharpness throughout photo taking. So instead of taking the aperture up a little ,I would take it up to say F22 and the shuttersped would be to low. Instead of gradually trying out the different apertures I am one of those all or nothing people either shooting 2.8 or 22. I Should have been more gradual in my approach. Thats why I bought this camera so I could learn. Its just tough when you blow great photo opportunities like I did. Therefore, I got a lot of fuzzy looking pictures or pictures of say a fence post in focus and everything else down the valley not in focus. The main thing I wanted to get out of posting was is there a rule of thumb on picking the aperture for snap shots at sights like above. Like try F11 see if shutterspeed is fast enough if not take the iso up a notch. Something like that. What I found after reading some more on the subject is that it is not clear cut as that. I will take a trypod on my next landscape adventure and do some tests with F11 through F22 and see what I like. The cool thing about photography is all the types ie. Candids, Landscapes, Nature Photography. They all take different approaches and no-how. Just when I think I get one type I try one of the others and hopefully learn something I can apply twards all of them.

Thanks for the help guys.

[Webster]

Anything over F11 is useless on the 10D...F8 being the sweet spot.


I'd hate for this to start up all over again - there was a huge long thread on this topic not that long ago - but I just could not let this go unremarked.

The aperture of the lens is the size of the hole, or opening, that light passes through. The f-stop is actually an algebraic formula that determines the physical size of the opening for any focal length of lens. The formula is this: focal length divided by f-stop equals the size of the aperture. When we say the aperture is f/8, we are saying the size of the opening is the focal length of the lens divided by 8. Since the focal length is always expressed in millimeters, the formula gives the physical size of the opening in millimeters. Simple rules of algebra tell us that as the value of the denominator increases, the value of the expression decreases. So larger f-stops equate to smaller openings.

Smaller apertures (larger f-stops) create more Depth of Field. The smaller the aperture, the more stuff there is in focus. If aperture were the only factor involved, we would all be using f-2000 all the time and keep everything in focus. Two things keep us from doing this. The first is pretty obvious. The smaller the aperture, the less light gets through, and longer shutter speeds are needed for proper exposure. This can be somewhat offset by increasing the ISO, but higher ISO brings higher grain and/or noise, so that's a limited option.

Even if we could use an essentially unlimited ISO without penalty there would be another factor limiting our use of smaller and smaller apertures. Whenever light shines across a hard edge there is a little bit of scattering of the "rays" right at the edge. Some of the photons that skim close to the edge decide to peek around the corner to see what's there and go flying off in another direction. This is called diffraction. When all the edges of a circular hole get close enough - that is, when the hole gets small enough - more and more photons become involved in the diffraction dance until the hole is so small that diffraction's all you get.

There is an immense amount of literature on how diffraction affects photographic lenses and cameras but it all boils down to the understanding that when the aperture reaches a certain absolute size loss of sharpness caused by diffraction becomes a factor to consider. With 35mm film cameras, conventional wisdom states that diffraction will start being noticable around f/22. With the D60/10D and their smaller sensor, we have to start being concerned around f/13. Because f/13 is considered a half-fstop, it is often stated that the smallest aperture we should use is f/11.

This is a LONG way from saying that anything smaller than f/11 (really f/13) is useless. It's just that the ever decreasing sharpness due to diffraction starts getting noticable at that point. And while the focal length of the lens is a factor, it is not the only factor. Like everything else in photography, it's up to each of us to go forth and shoot lots of frames and judge for ourselves how the balancing of all these factors affects our personal shooting habits. Being lucky users of digital SLRs, we can all do lots and lots of this kind of zero-creativity shooting without incurring any processing or even storage costs. So stop reading this (if you haven't already) and get out there and find out for yourself!

[Jorge]

Webster it's good when someone takes time to explain something like this. I usually forget to use the higher apertures when taking landscape shots and the like. I just searched for a DOF calculator and was a little surprised by the results.

Let's say I shoot a landscape with something in the foreground 5 meter away. I shoot with 17mm using f4, focusing on the forground object - will the background also be in focus?? Well according to this calculator it will:

http://www.shuttercity.com/DOF.cfm

Is higher apertures not needed with wideangles?

[PPi-]

webster wrote:
There is an immense amount of literature on how diffraction affects photographic lenses and cameras but it all boils down to the understanding that when the aperture reaches a certain absolute size loss of sharpness caused by diffraction becomes a factor to consider. With 35mm film cameras, conventional wisdom states that diffraction will start being noticable around f/22. With the D60/10D and their smaller sensor, we have to start being concerned around f/13. Because f/13 is considered a half-fstop, it is often stated that the smallest aperture we should use is f/11.

This topic have never been easy for me to perfectly comprehend. From what I have understood this far is that it is not about smaller sensor side but smaller pixel size, am I right? Smaller sensor just means that the image is cropped down, eg. we take scissors and cut the traditional 35mm film into smaller size.

Huh, I should stop reading these forums, as day after day I get feeling that everything is wrong with the digital cameras today on market (except propably those $$$$$ cameras with full size sensors). On the other hand I really don't want to look back for the film anymore. Just spend an evening cleaning dust and scratches from scans... I really want to go out and buy DSLR soon.

[robertwgross]

PPi- wrote:
...
Huh, I should stop reading these forums, as day after day I get feeling that everything is wrong with the digital cameras today on market (except propably those $$$$$ cameras with full size sensors). On the other hand I really don't want to look back for the film anymore. Just spend an evening cleaning dust and scratches from scans... I really want to go out and buy DSLR soon.

Almost one year ago I purchased a Canon FS4000US scanner to do slides (or maybe negs, if I had to). It has the feature that detects dust spots or scratches (by IR) and then edits those out of the finished image automatically. So, I spend my evenings doing other things.

I shoot film half of the time and digitally half the time, so I keep one foot in each world. Then I start arguing film versus digital with myself!

---Bob Gross---

[RichardtheSane]

Just something to add... When it comes to landscape photography I decided it was time to learn about hyperfocal distance. I now use that nearly all the time for my serious landscape shots.

I shoot film half of the time and digitally half the time, so I keep one foot in each world. Then I start arguing film versus digital with myself!
Bob, I have the same debate on a regular basis. I am getting myself a cheap film scanner soon so I can post a few 'digital' images from my slides :D

[DAMphyne]

PPI Wrote:
This topic have never been easy for me to perfectly comprehend. From what I have understood this far is that it is not about smaller sensor side but smaller pixel size, am I right? Smaller sensor just means that the image is cropped down, eg. we take scissors and cut the traditional 35mm film into smaller size.

Just an observation about pixel-size vs sensor size.
When I used a 35mm camera, the "sweet-spot" seemed to fall around f8-f11, with a 4x5 camera the spot was around f64 maybe even f128, depending on the lens.
I think the size of the film(sensor) does have a lot to do with the DOF-sharpness.
Just a thought.

[Webster]

Huh, I should stop reading these forums, as day after day I get feeling that everything is wrong with the digital cameras today on market (except propably those $$$$$ cameras with full size sensors). On the other hand I really don't want to look back for the film anymore. Just spend an evening cleaning dust and scratches from scans... I really want to go out and buy DSLR soon.

The loss of an f-stop due to the smaller sensor is really an advantage for the D60/10D, not a liability, since the 1.6 focal length multiplier means that, to get the same picture you'd get with a 35mm film camera, you'd use a shorter focal length, and get the greater DOF that comes with that. They pretty well balance each other perfectly, except that the larger aperture on the digital camera gives us another stop on the shutter.

The only effect pixel density has is that the higher densities allow us to see the effects of the optical degradations caused by the physics used by the lenses.

[daveh]

PPi- wrote:
This topic have never been easy for me to perfectly comprehend. From what I have understood this far is that it is not about smaller sensor side but smaller pixel size, am I right?.

No it really is the smaller sensor size for diffraction. Smaller sensor, means greater enlargement for any given photo size which means more magnification of diffraction. (On the other hand, you need smaller apertures to get the same DOF with larger formats and smaller apertures mean more diffraction so things kind of balance out.)

On the other hand pixel size comes in on issues like sensitivity and noise.

You'll note that some of the "trouble" threads from people with their first DSLR are due to how LARGE the 10D's sensor is rather than how small. It's easy to get a ton of DOF with a high shutter speed with a tiny imager (film or digital.) On the other hand you'll see the large format users using their tripods in full sun to take landscapes. That's because they need to shoot at f-stops that you don't even have to get some DOF.

[DAMphyne]

Daveh,
You are so right, I think you said it perfectly.
Although, a larger sensor(film,pixel count) will gather more information(details).

[scollins]

Being lucky users of digital SLRs, we can all do lots and lots of this kind of zero-creativity shooting without incurring any processing or even storage costs. So stop reading this (if you haven't already) and get out there and find out for yourself!

I can really appreciate this kind of advice. First, thank you for explaining the process in such detail. I'm sure it's been done here before, but it's the first time I've seen it explained like that.

Secondly I love the advice about getting out there and just taking some pictures. It is one of the beauties of DSLR's and digital photography in general, that there is no penalty for taking hundreds of shots when experimenting.

[PPi-]

Thanks guys, I think I'm slowly getting it now (what can you do if you are just being this hard headed?). Actually it is being quite neat to have that large DOF with smaller f-stops.

On the other hand we need 'faster' lenses for situations where we want to reduce the DOF willfully. Ok, this is possible but these lenses just costs some more and may get bigger sized.

I might return asking some advices about my upcoming purchasement after the month changes. I want to have some second opinions about the things and equipment that I've thought this far. But until then... I'll be watching you ;-)

PS. Oh, and Bob, thanks for the advice of the scanner but I think I'll keep my old and take better step into the digital world soon. It just have some advantages that I want to have. :)

[robertwgross]

PPi- wrote:
...
PS. Oh, and Bob, thanks for the advice of the scanner but I think I'll keep my old and take better step into the digital world soon. It just have some advantages that I want to have. :)

Last November, when I bought my Canon scanner, it cost about $1000. Now I see that some vendors are selling it for as little as $600. I guess that shows what a little competition will do.

---Bob Gross---

[daveh]

PPi- wrote:
On the other hand we need 'faster' lenses for situations where we want to reduce the DOF willfully. Ok, this is possible but these lenses just costs some more and may get bigger sized.

Yes, big chunks of high quality glass don't drop in price the way electronics do. I recommend slowly building a collection though because they're really nice to have. You can slice the world quite thinly with the 85 f1.2 when you need to.

[PPi-]

robertwgross wrote:
Last November, when I bought my Canon scanner, it cost about $1000. Now I see that some vendors are selling it for as little as $600. I guess that shows what a little competition will do.

I suppose the same goes soon for me when I get digital body. It is a electronic device and soon 'absoleted' as new models come and go. Have to live with that.

Thanks for the tip, daveh. I'm eyeing possible lens selection now that I could get started with. Maybe I'll get something cheap at first stage so that I can start photographing with new equipment and upgrade later. I'll have only limited amount of money to put for investments at the moment. Otherwise I need to break into local bank but not wanting to do that as I'm still being young and handsome ;)