Tagged Questions
11
votes
4answers
264 views
Why aren't lenses designed with extra large apertures for autofocus beyond what's used for imaging?
Historically, designing large-aperture lenses has been difficult because correcting the optical aberrations that arise from large apertures requires complex designs and very large amounts of glass. ...
2
votes
1answer
276 views
autofocus and maximum aperture of 60D [duplicate]
Possible Duplicate:
What are the aperture limits for autofocus on Canon DSLR cameras?
It is mentioned on page 79 of the EOS 60D manual that the center point AF is twice as accurate at ...
6
votes
6answers
1k views
Is it important that the Canon 1DX isn't specified to autofocus with lenses slower than f/5.6? [closed]
Seeking the lens market AND the related info WRT Canon 1D X, I found some things which seems concerning:
1st, a note from Canon's Chuck Westerfall (see here) saying:
“AF is unavailable on the ...
31
votes
3answers
6k views
What apertures are required to enable autofocus, including cross-type or high-precision focusing, on Canon DSLR cameras?
This is a follow-up to Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers? I'm doing this to separate the AF aperture requirements from the linked question above. My goal ...
10
votes
2answers
3k views
Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers?
One thing that I've noticed with Canon DSLR camera is they will disable or limit autofocus when the lens is below certain aperture values, which are specified in my answer to What are the aperture ...
4
votes
2answers
658 views
AF-D vs AF-G: is the aperture ring necessary?
I just purchased a Nikon D7000 with an 18-105 f/3.5-5.6 AF-S lens. I'm also looking at purchasing a lens around the 200-300mm focal length range, and I found the 70-300mm f/4-5.6 AF lens. As far as I ...
10
votes
4answers
433 views
Focusing on moving target with large aperature?
I have read about difficulties getting focusing right when using a large aperature (because of depth-of-field issues).
If I am using a fast prime wide open (say F1.4 or F1.8) to shoot a target in ...
