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

Started Oct 27, 2007 | Discussions thread
Amin Sabet
OP Amin Sabet Veteran Member • Posts: 6,763
Re: No need to be careful -- I'll accept the results.

joe mama wrote:

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.

Do you know a lens that has it's best center sharpness wide open and gets worse stopped down one stop? PZ says their 28/2.8 does this. Also, look at the MTFs from Canon. 24-85 at 24mm takes a huge hit at the edges.

28/1.8 does the double dip - gets worse moving out from the center, then better again a little further out before taking the big dive at the edge:

28/2.8 does a similar double dip though less pronounced. Based on MTF, it would be expected to have the best f/8 corners of the three.

At f/11, my 28/2.8 had better extreme corners than my 24-105L. Here's someone else's comparison against 13 other lenses at 28mm tested on a 5D ->

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

I think an even more ideal comparison would be the 14-42 on 4/3 vs 28-105 on 35mm or better yet, 28-90 II on 35mm.

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.

Do you agree that there is an appreciable sudden dropoff in the 5D system image extreme corners relative to the rest of that photo whereas the E-410 system shows worse global quality without the same degree of dropoff in the corners relative to the rest of the photo? I thought that your predictions were at odds with that outcome.

 Amin Sabet's gear list:Amin Sabet's gear list
Nikon D500 Panasonic Lumix DMC-GX85 Sony a9 Panasonic Lumix G 14mm F2.5 ASPH Panasonic 20mm F1.7 II +11 more
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