Corner tests for 16-35 f/4 vs. 16-35 f/2.8 (v.1) vs. 24-70 f/2.8L II

Started Jul 4, 2014 | Discussions thread
Just another Canon shooter
Just another Canon shooter Veteran Member • Posts: 4,691
Re: Corner tests for 16-35 f/4 vs. 16-35 f/2.8 (v.1) vs. 24-70 f/2.8L II

Abu Mahendra wrote:

Yes, I got it then. And I get it now. The thing is that:
1. Not all lenses suffer from FC, and if they do, not necesarily to the same degree. Has the EF 16-35IS been verified to suffer from this?

Yes, see this, of example, taken from this thread. A quote:

It's really incredible tricky to do valid real world tests. I was noticing that just a little flick of the focusing forwards or back, super tiny, can totally change how a lens seems to do at near front corners vs mid distance vs distance. And even just doing one focusing trial on a given object in the scene can easily make for slight differences between attempt and each attempt can paint a noticeably different picture at different corners and parts of the frame.

And trying to do real world tests where you try balance focus from near to far is tricky since it's hard to remember exactly how you balanced it so when you test the second lens or even the same one again you can end up with results that are different each time. Heck on one trial I actually got an f/6.3 to seem to show a larger part of the scene 100% crisp than an f/8 shot, since I had ended up slightly front corner biasing more than I had thought.

2. UW lenses are not always and by all used for maximum sharpness across the frame stopped down. I, for one, don't most of the time.

This is the point of this thread. If you have a different goal, go back to your old thread and try to lecture me there.

I am not trying to say that this lens suffers from field curvature. I am trying to warn the OP that it may suffer thus affecting the results of the test; and this may be the case for the other lenses in the test, invalidating the comparison. The 24-70II used in the test has been reported to suffer form filed curvature as well.

Got it now? I am not very optimistic.

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