Portrait Aperture

[Theo]

I'm been playing around with my new lens, a Canon 50mm f/1.8.

One thing I'm not sure about is the aperture to use when taking portraits. I'm normally outside taking photos of moving children. I don't think f/1.8 is the best for this situation since the depth of field is so small so I'm wondering what aperture you guys would recommend.

[sybren]

If your servo/continuous AF is fast enough you should still be able to shoot those children at f/1.8. Don't count on many of them being in focus at the same time, though ;-)

[wulf]

Try several options and see what you like. You have to figure in not just accuracy of focus but also factors like distance (the other variable influencing depth of field) and light levels (hence what shutter speed / ISO options you have for decent exposure, with their own attendant side effects).

Wulf

[RichardTaylor]

Re portraits and aperture:
Depends on what you want..

(1) Show some of the background without overpowering the subject.

Camera: Canon EOS 5D (Full frame)
Exposure: 0.025 sec (1/40)
Aperture: f/4
Focal Length: 24 mm
ISO Speed: 1600
Exposure Bias: -2/3 EV
Flash: Flash did not fire


(2) Kill the background.


Camera: Canon EOS 40D (1.6 crop camera)
Exposure: 0.001 sec (1/1000)
Aperture: f/2.0
Focal Length: 135 mm
ISO Speed: 400
Exposure Bias: 0 EV
Flash: Off, Did not fire

(3) Show the subject in the environment.


Camera: Canon EOS 5D (full frame)
Exposure: 0.01 sec (1/100)
Aperture: f/9.0
Focal Length: 80 mm
ISO Speed: 800
Exposure Bias: -2/3 EV
Flash: Off, Did not fire