Close up shots: Sharpness/Diffraction of (My) M43 lenses

Started 4 months ago | Discussions thread
Jonas Palm Senior Member • Posts: 1,084
What it also shows is...

knickerhawk wrote:

alcelc wrote:

knickerhawk wrote:

You've angled your subject and based your evaluation of optimal aperture on a portion of the subject that is in front of the focus plane. Therefore, it comes as no surprise that the shots with larger f-numbers (deeper DOF) do better than the shots with lower f-numbers. If you evaluate closer to the center of the focus box (more around Washington's eye), you'll see that the lower f-number shots are sharper in the actual focus plane. Not only is the eye sharper, there's clear evidence of aliasing in a number of the lower f-number shots in that center area, as would be expected.

If judging on the right eye of Washington (the area of focusing), basically most lenses in the test are in similar sharpness from wide open to f/11. A few started to look worse from f/16 and all of them looking bad at f/22. The places of references are max 2.5cm from the focus box, should be much closer than the usual test result used by DXO on 1/3 from center sharpness...

Regarding the morie, on the pattern-wise they should be good at 1:1 view on my monitor.

Still need more time to analysis on the color morie side...

Thank you for your comment.

Here's a side-by-side crop of the f/11 and f/3.7 samples from the 12-32mm lens. They've been upsized 400% because (as you note) the differences in the focal plane sharpness is not great.

Top=f/11; Bottom=f/3.7

There's a fair amount of false detail in both, as would be expected, but note how the f/3.7 has slightly more contrast. Note how it also has some slightly purplish/greenish coloring (relative to the f/11 version). Note how some of the blurred out patches in the f/11 version show apparent (but false) detail in the f/3.7 version. This greater amount of false color and detail (along with the better contrast) in the f/3.7 version is indicative of it being the sharper rendering in the focal plane.

Speaking of focal plane, below are the two shown side-by-side again at 400%. Note how much more blurred the f/3.7 version is relative to the the other crops that are in the actual focal plane. However, this example may be confounded by what looks like possible shutter shock.

Top=f/11; Bottom=f/3.7

What it also demonstrates is that even a modest lens like the12-32 is limited by sensor resolution, as evidenced by both the aliasing and that all lenses are very similar in the focal plane at less diffraction affected apertures.

Which is confirmed by my own flat field, non-closeup tests.

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