philber Offline Upload & Sell: Off
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I don't think it affects only wide angles. The Summilux 50 ASPH is a good example of what Fred describes. I couldn't get sharp corners at infinity before f:8.0. I thought it was a mismatch with the sensor and registry, until I focused the corner itself and noticed how much better it was, but the image centre was OOF. That suggested field curvature. A blogger called 3D-Kraft proved it to my satisfaction in a picture of wavelets in a harbour. Massive field curvature can be seen readily, where wavelets are sharp on the sides, and very much OOF at the same distance, but in the centre.
I am right now testing 2 28mm Olympus, a f:2.0 and a f:3.5. The difference in "apparent DOF" is striking, where there should be little or none. This is interesting, because they are DSLR lenses so, in theory, unaffected by the short registry and the "compatibility" issues. Also I shoot both with the same adapter, which equalizes that part of the equation.
That suggests, though I not through with testing, so I am only tentative, that the A7R is a lot more revealing of transitions from in focus to OOF than 5DII and 5D III which I used before, also with FF lenses. That said, the fact that 100% magnification is far greater on the A7R also plays a significant part in revealing the problem IMHO.
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