Corner sharpness: Four Thirds vs 35mm (bandwidth warning)

Started Oct 27, 2007 | Discussions thread
joe mama Forum Pro • Posts: 12,623
No need to be careful -- I'll accept the results.

Alway keep in mind that those tests are on a 1.6 crop sensor. The
tester included on the resolution section:

"As hinted above the EF 24-85mm f/3.5-4.5 USM received some rather
mediocre reviews during the mid ´90s. However, all these reviews were
based on full frame analysis. When looking at the original Canon MTF
figures the lens is very good except at the borders. On APS-C DSLRs
the borders reside way beyond the cropping factor and this also shows
up in the Imatest measurements. On the EOS 350D the lens is capable
to deliver a very good to even excellent center performance combined
with marginally worse borders. Very impressive and basically as good
as the pro-grade EF 24-70mm f/2.8 USM L (again: just on APS-C DSLRs).

It would be surprising to me to find that the 24-85 / 3.5-4.5 performed better than the 28 / 2.8 in the "corners" of 1.6x but worse in the corners of 35mm FF. I can't think of any reason why the prime should be sharper in the center, softer in the mid (corners of 1.6x), and then sharper in the edges again. I know of no lens that exhibits such behavior.

In any event, I would certainly wecome a test of zoom vs zoom: the 14-42 on 4/3 vs the 24-85 on FF. I think that's an ideal comparison.

Remember, I have no agenda except the facts. If the facts invalidate my theory, then I will change the theory to fit the facts. However, as I see it, this test is exactly in line with what I would have predicted. No surprises to me.

So much thanks to Amin for an excellent comparison. I would welcome further comparisons of this sort.

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