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

Started Sep 14, 2013 | Discussions thread
OP Benedict Slotte Senior Member • Posts: 1,165
Re: Consensus on 24-70/2.8 II field curvature at infinity focus?

My lens has field curvature, with soft edges as a result focused at infinity.

And the “cure” is to focus beyond the infinity mark. For a start, focus using live view, aperture set at 8, place the focus point in one of the far edges, stop down and manual focus until the edge is sharp. You will by trial and error find the “magic focus point” that will bring both the center and edge/corners pin sharp.

This is what I tried to achieve too - using somewhat offset microadjustment. However, I was unsuccessful at getting a sharp center at the same time. Tweaking focus using live view across the frame is of course possible, but kind of annoying.

Another copy I tried was sharp as a knife both in the center and at the right edge, but mushy on the entire left side... There is just a lot of variation going on between copies. The excellent AF of the 1D X just makes any such inconsistencies even more obvious.

It seems to me that the 24-70 L II is not really such a good landscape lens after all.

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B. Slotte
Turku, Finland
http://bslotte.smugmug.com

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