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Consensus on 24-70/2.8 II field curvature at infinity focus?

Started Sep 14, 2013 | Discussions thread
Armin Hermann Regular Member • Posts: 299
field curvature, hyper focal distance and sample variation
2

Benedict Slotte wrote:

I have tried a few copies of this lens, and settled on the one that was best among them.

Benedict, thanks for binging this up. I'm in a similar situation as you are. I always do buy several samples of a zoom lense and pick the best. I have seen great sample variation with tamron (as expected). With the Nikkor 80-200 2.8 there was non at all ( 3 samples), and the Nikkor 18-35 2.8 had extensive variation also. As i'm just switching platform, i have no experience with canon (actually i have, but thats 20 years back). Can you desribe how the samples differ and did you test several focal lengths or just one? I expect corner resolution to vary mostly, right?

In spite of this, I do see significant field curvature in landscape shots (read: focused close to infinity) even at f/8, meaning that not even at f/8 will it be possible to have decent sharpness from one edge to the other.

To my best knowledge field curvature is not really subjected to sample variation (lense alignment), but is a design limitation.

The only thing you can do about it is to harmonically optimize diffraction and hyperfocal distance.

-Armin

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