Comments on MFA

[neuroanatomist]

By the way, depth of focus is different from depth of field.Depth of field deals with object space, such as the person that is 10 feet away with 5 inches DOF, while depth of focus deals with image space, such as the tiny fractions of a millimeter in front of and behind the sensor.

Yep - I knew this, but when I asked the question of Chuck I didn't think through to the fact that any specification related to the AF sensors would have to be based on depth of focus, not depth of field. Chuck corrected me as well.

Very interesting. Wouldn't be the first time he was wrong, but I'm surprised he's so specific and adamant about this.

Me, too. I asked the question because your explanation and excellent analogy seemed logical to me at the time.


Of course, this has major implications for very fast (e.g. f/1.4-1.2) lenses. With off-center AF points, the depth of f/5.6 focusing precision is going to be much wider than the depth of field at f/1.2, and even when using an f/2.8 high-precision center AF point with 1/3 depth of focus precision, that zone offocusing precision will still be wider than the actual depth of field (depending on subject distance).


@<span class="user-name"]<span>HDNitehawk, I think you've got it...