Question on f-stop

RL168

TPF Noob!
Joined
Feb 18, 2007
Messages
11
Reaction score
0
Can others edit my Photos
Photos OK to edit
Hello,

I have a basic understanding on shutter speed, aperture and how aperture affects DOF. Since I got my camera, I have been taking pictures in manual mode playing with different settings. But I was wondering if there is a rule of thumb on what f-stop do you use for different photos you are taking. For example, if you want to take a landscape photo, what f-stop will you use? Same thing for sport, portrait and etc. I realized I might learn this as I take more photos and gained more experienced. But I think those rule of thumb settings will help a beginner. If you have any advice to share, I would really appreciate it.
 
1) Many of my landscape photos are with f/8 to f/16 .. the latter only if I really need a lot of DOF since there is some foreground and background which should be equally included.

But there might be the shot where I want that object in the foreground to be in focus , with a blurred mountain scenery in the background, then it would be more f/4 and anything below.

If there is low light and no tripod with nothing important in the foreground, I might also use f/4 to keep the exposure time short enough for handheld.

These numbers now refer to sort of not to extreme focal lengths between 30 and 60mm, with ultrawide angle things can be very different again.


2) For architecture I often use quite small apertures if with a tripod, f/8 to f/16 again .. unless I want very selective DOF on one aspect of the architectural scene.


3) For sports / to freeze motion (short exposure, or shutter speed as they call it) you will almost always go for large apertures, as large as your lens can give sometimes.


4) Wildlife with my 300mm, almost always at f/4 or f/5.6 .. unfortunately my lens does not allow for less.


5) doing macro with 300mm or 400 + close up lens, I often go for the smallest possible aperture, since DOF might be too shallow else.

Those are just my personal preferences
 
For example, if you want to take a landscape photo, what f-stop will you use? Same thing for sport, portrait and etc.

What camera and lens are you using? If I'm shooting landscapes with a 35mm SLR and a 50mm lens I'd probably go with f/16 or f/22. If I'm using an APS-C DSLR, and an 18mm lens f/5.6 might be more than enough (5 feet to infinity when focused at about 9.5 feet), and going smaller than f/11 can cause aperture diffraction issues. With a 4x5 and a 150mm I'll go with f/64. You get more DOF for a given f/stop with a shorter focal length lens. Aperture diffraction becomes an issue sooner for smaller formats.

Aperture diffraction http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm

DOF calculator http://www.dofmaster.com/dofjs.html
 
Guys,

Thanks for the advice. I really appreciate it.

I am using a Nikon D200 with 18-200mm lens.

rl168
 
It all depends on "your vision" of how the scene looks. That is to say how you want to interpet it. Kind of what Alex B was saying about personal preference.
 
Guys,

Thanks for the advice. I really appreciate it.

I am using a Nikon D200 with 18-200mm lens.

rl168

You also have to understand that depth of field is affected by more than just the fstop.

Distance from camera to subject will greatly affect the depth of field. That's why in Macro photography the dof is so small. The closer you are to your subject the smaller the dof will be. Take a shot at 18mm of a subject 10' away at your camera's smallest max aperture. (I guess f5.6). Now move to camera's closest focusing and take the same shot 18mm f5.6 and look at how out of focus the background is.

Also Focal length affects the depth of field. Take a shot at 18mm of a subject 10' away at your camera's smallest max aperture. (Again I guess f5.6). Now this time stand in the same position and zoom to 200mm and take the shot at f5.6 and you'll again see a huge difference in the dof.

Combine both above (move closer and increased focal length) and the fstop to get the dof you want. Remember also that if the subject is close to a background the depth of field may still show this in focus so get the subject away from the background which is great for isolating the subjectin the frame.

What you need to do is work out what depth of field you want in a particular shot. A portrait of a single person you may want a shallow dof and shoot at f2.8 (or in your case around f5.6), However if you are shooting a group of people, to get everyone in sharp focus you may need to shoot at f8 (depending on the focal length). Remember the wider the focal length the greater the depth of field at any given fstop.

Hope this makes sense.

Regards
Jim
 

Most reactions

Back
Top