Sort of evaluation of some macro lenses (not MF)

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Erik Kaffehr
Erik Kaffehr Veteran Member • Posts: 6,177
Sort of evaluation of some macro lenses (not MF)

In part due to some discussions on this forum and also because I got renewed interest in macro photograph, I have spent some time evaluating macro options for my photography.

As macro options for the GFX were discussed, I felt that it would be appropriate to share my findings.

I essentially looked at three lenses, Sony 90/2.8G, Laowa 100 mm APO Macro and Photar 25/2.5.

In the end, I just looked at central and corner crops at 1:1, 2:1 and whatever I got with the Photar.

I focused manually with an RRS focusing rail. Focus was based on peaking at magnified live view.

These are central crops at actual pixels, straight out from Lightroom, with sharpening set to preset 'low'. Note that only parts of the images are in focus.

Corner crops. Laowa only as I don't think that the Photar can cover 24x36 mm at the magnification range I am interested in.

Just to say, this is not Jim Kasson quality testing.

What I can see from this?

I would say that neither lens is really sharp on a 3.8 micron sensor, but I would think that good sharpness could be achieved with a bit of more aggressive sharpening.

The Photar can resolve impressive detail, in the area of best sharpness.

In the end, I would think that the great challenge is depth of field and diffraction.

Just to say, I did make some testing with a Cognisys rail, but I am more confident in these images.

Shooting apertures varied from f/4 to f/5.6 for these images.

How does this translate to medium format?

My guess would be that the Laowa would cover 33x44 mm, but I cannot test. It also seems that the Canon version won't work on Fujifilm GFX.

As the pixel design on the GFX 100/100S and the Sony A7rIV used here are essentially same, the on axis results would be the same on the GFX 100.

Corner used is ca 20 mm off axis on the A7rIV, so it is like a crop at the center of the short edge on the GFX 100.

Does the Photar cover 33x44 mm. Not at 12.5 cm extension, as used here. At longer extension may be.

But, as shown here the object side resolution of the Photar 25/2 at optimal aperture is around 1.5 microns. So, assuming 4X magnification the blur circle may be around 6 microns. So increasing magnification will not resolve more detail.

Best regards

Erik

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Erik Kaffehr
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Magic uses to disappear in controlled experiments…
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