Auto focus speed

Started Jan 6, 2011 | Discussions thread
stasvolik Contributing Member • Posts: 569
Re: Auto focus myths

Marianne, does it mean that Nikon AF cannot focus lenses set to aperture faster than F5.6 with a precision better than F5.6? IOW, it seems to me that a lens set to F2.8 need to be focused with a greater precision than F5.6 lens due to shallower DoF. Canon brags about F2.8 sensors in their higher end bodies, Olympus used to tout their dual sensor AF system in E3. Somehow I was unable to find the answer to my question by googling.

Marianne Oelund wrote:

Myth #1: AF works faster/better or in lower light with faster lenses

Not true for AF systems such as Nikon's, in which the AF sensors only receive light from the f/5.6 exit pupil of the lens. All of the additional light provided by lenses faster than f/5.6 is peripheral to that pupil size, and doesn't reach the AF sensors.


 stasvolik's gear list:stasvolik's gear list
Nikon Coolpix 5400 Nikon D300 Nikon 1 J3 Nikon AF Nikkor 180mm f/2.8D ED-IF Sigma 17-50mm F2.8 EX DC OS HSM +6 more
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