f4 for zooms plus a few primes vs f2.8

[Daniel Browning]

Do you (or does anybody else) manage to successfully use the f/1.8 primes wide-open for non-staged shots of relatively fast-moving subjects like small children?

Yes, but it's very difficult. There are several things you can do to make it easier. Try to tune autofocus into the best performance. Get a different viewfinder screen (they show thinner DOF). Try live view. Prefocus on a certain spot and snap it as the subject moves into it. Only attempt wider compositions such as environmental portraits instead of closeups. Arrange yourself so the DOF is parallel to the movement of the subject. Focus bracketing: rapid fire a lot of shots at slightly different focus or subject position. I'm sure there's more tips and tricks.

[Colin500]

Thanks to everybody for all the ideas and hints; the first thing I tried is switching into servo af and/or shooting several pictures in rapid succession, and that already helps a lot.


Regarding the "DoF parrallel to the movement", is the focal plane typically a really flat plane? (I suppose it can't be spherical, at least not with the camera (sensor) as center point, because otherwise focus-and-recompose would work better&hellip


Regards, Colin

[Daniel Browning]

is the focal plane typically a really flat plane?

Typically it's pretty close. When it's not (like in my Tamron 17-50 f/2.8), it's called "curvature of field".