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Can anyone give their opinion of the sharpest F stop for the following lenses
(assume all other factors are constant)
(all canon lenses)
70-200 f2.8 I L
17- 40 f4 L
24-70 f 2.8 L
50 f 1.4
135 f 2 L
In general my recommendation has been two stops above the widest aperature and kess than f 11
Can anyone be more exact
If your recommendation of f/11 is based on the impact of diffraction, you need to specify what body you're talking about, since pixel size affects the aperture at which diffraction starts to affect sharpness.
You might try the MTF50 graphs at Photozone, where they plot resolution vs. aperture at different positions in the frame (and at multiple focal lengths for zoom lenses). For example, the 50/1.4 on a 5DII is sharpest at f/4 (3 stops down from max), and by f/11 it's down to where is was at f/2.
Quote:
Originally Posted by neuroanatomist
Here is another good site that gives a good graphic of sharpness.