 M |
What numbers or f-stops do I use when shooting? I'm a newcomber to photography and found that when using shutter/aperture priorties, the highest and lowest stops {as well as all stops in between}, in various situations, captures speed/motion, low-light situations and depth of field. However, how do you know WHICH numbers or stops in between to use? I know the numbers can vary from situation to situation, but, didn't know if anyone might have a chart or something that can be used for example situations. Thank you for your help.
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M |
I also forgot to ask: Would the shutter/aperture settings differ with lenses? I would mainly be taking photos outdoors (nature/people) or indoors (snapshots) with a 28-90mm lens. and will be getting the next lens size up in the future. Thank you.
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Michael H. Cothran |
In truth, you really don't know. However, in effect, here are some guidelines to help: The range of apertures your lens has (and I won't go into the optical descriptions of the 'numbers' that represent each f-stop) is the same from lens to lens. F2.8 on any 28mm lens will give you the same depth-of-field. However, f2.8 on a 100mm lens will be less than f2.8 on a 50mm lens, which will still be less than on a 28mm lens. At any given aperture, there will be less depth of field on a longer focal length, and more depth-of-field as you go to wider lenses. The smallest aperture on your lens will give you the greatest depth-of-field, while the largest aperture will give you the least. As you close down your lens, that is, go from f2.8 to f4 to f5.6, etc., the depth-of-field will increase. There have been many charts devised to help determine exactly what your depth-of-field will be at a given f-stop on a given focal length at a given distance, but whew!, it's more than a mere mortal wants to cope with. Now here's something which you can probably use as a starting point. Lenses, in general, perform best at 2-3 f-stops down from wide open. If you were to chart a lenses resolving ability, it would look like an upside down 'V' skewed to the left. Your worst apertures are usually wide open and all the way closed down, so normally you would want to avoid these. On a lens with a maximum aperture of f2.8, f3.5, or f4, your sharpest shooting will occur between f8 and f11, which also give you moderate depth-of-field. F5.6 and f16 would also still be quite acceptable. Thus, use f8 to f11 whenever you can, and only stop down more if you have really near and far subjects in the same scene,and need lots and lots of depth-of-field. And open up past f5.6 ONLY if you are shooting in dimly lit areas or you just want to really throw the background out of focus. Let me reiterate one more time - use f8 to f11 for most 'normal' shooting, remembering that you can stretch to f5.6 and f16 with little deteriation in image quality, and use the other f-stops only when you absolutely need to. Hope this helps. Michael H. Cothran
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M |
Thank you so much! I know in creative photos there are no borders, but your answer helps a lot. Thank you. Would you have any recommendations on any good books or sites that would contain photos with what f-stops were used? ~M
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Michael H. Cothran |
Your best bet is to see for yourself. Do some personal testing. It's fun! Here's how: First - be aware of this - many photographers will choose a small aperture when they are shooting a landscape at infinity, since they mistakenly believe they need lots of dop - WRONG. If all of your subject matter is at infinity, your image HAS NO dop, thus you can shoot wide open if you want. In the case where you have less dop, then it only stands to reason that you would want to shoot at the best aperture your lens has (which on your 28-90 should be in the f8-f11 range), providing it gives you a useable shutter speed. Now, that said - Start with a people shot (wife, girl friend, etc - but not both in the same picture, ha!) - put your camera on aperture priority, and find outside light where your camera can provide a useable shutter speed for all your marked f-stops. At 90mm, shoot head shots, 1/2 torsos, and full length shots at EACH marked f-stop. Then do the same thing at 50mm, and then do the same thing at 28mm ( and don't worry that your head shots look distorted @ 28mm - your objective here is to study the dop affects). Then, study closely the range of f-stops for each set of pictures. You should see a marked difference between f2.8/f4 and f16/f22. However, if your eyes scan from f2.8 to f22, you'll find that the increase is ever so slightly from one f-stop to the next. You'll learn that it is not as abrubt a change as you might have expected. If dop is important, then close down one more f-stop than you think you need. If your camera has a dop preview, use it. Back in the good old days of single focal length lenses, determining dop was easy, as all good lenses had hyper-distance scales to show you your acceptable area of focus at each f-stop. Since zooms change focal length, that is no longer possible. The only time dop really plays an important roll is when you have what we call a 'Near-Far' relationship in the image. For instance, you have a flower at your feet, and a mountain range in the background, and you want to have both in focus. Then, there is a 'trick' you can use - there is a dop rule where 1/3 of the acceptable area of focus will fall in front of where you are actually focused, and 2/3 will fall behind it. Thus, look at your flower, then look at the mountain range, and visually determine an area about a third of the way in from the flower. Focus on that area, and you are using what's called the 'hyper-focal distance', which will give you maximum dop with your chosen f-stop. Add extra precaution by choosing a small f-stop, f11-f22. In all honesty, to look at a picture where the photographer states he shot it at f11 doesn't really do you a lot of good, unless you also know the focal length, and where he focused in the picture (the hyper-focal distance), and how close and how far the near and far subjects were.
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