Macro photography with and without macro lenses

[Ken Lee]

I see a slight improvement with the Nikkor macro lens even at f/22.

How about off-center ? I should think we'd find greater differences as we reach the limits of coverage, rather than at the center where quality is optimal.

Also, at 1:1 what aperture makes these lenses diffraction-limited, where any comparison is of questionable utility ?

Since you're testing a macro lens, how about 2:1 or greater magnification ? Wouldn't the difference become even more evident by then ?

[cjj2003]

I see a slight improvement with the Nikkor macro lens even at f/22.

How about off-center ? I should think we'd find greater differences as we reach the limits of coverage, rather than at the center where quality is optimal.

Also, at 1:1 what aperture makes these lenses diffraction-limited, where any comparison is of questionable utility ?

Since you're testing a macro lens, how about 2:1 or greater magnification ? Wouldn't the difference become even more evident by then ?

These are all good points. Since I was using so much tilt, I sort of thought that I was testing the edge of the lens. The diffraction limit for this lens and digital sensor (Leaf Aptus 22) is around f/22 which is why I didn't test at smaller apertures.

The F//11 Rodenstock image appears the be out of focus.

It is very much in focus -- the quality is just really poor.

[cjj2003]

Technically, the diffraction limit is around f/11 because the effective f stop has increased by two stops at 1:1 magnification! However, based on my observations, I think diffraction doesn't become a major issue until somewhere between f/32 and f/22 for this setup.

[8x10 user]

The diffraction limit for this lens and digital sensor (Leaf Aptus 22) is around f/22 which is why I didn't test at smaller apertures.

Not at 1:1...

At 1:1 F/22 becomes F/44, the diffraction limit for F/45 is 35 line pairs per mm... 35 x 2 x 25.4 =1778 lines per inch

The sensor size for a 22 MP MFD cameras is 9 microns or ~2800 lines per inch (very close to the best results possible with chrome film and large format cameras, per inch)

However the images do not look that bad because the camera already uses interpolation to combine pixels from the bayer grid. In addition camera software is pretty good at sharpening images that are not quite tack sharp at 100%.

With my Sinar 54H (22mp multishot), I can see an improvement to the areas in focus (at 100%), when I use a slightly wider aperture then f/22. Although I often have to reduce my resolution 50% for many uses so the difference is often not noticeable.

With the F/11 rodenstock image I dont see an area infront of the plane of focus so its hard to tell. I do think the 210mm AM picture is focused to a slight farther away point in the image.

[8x10 user]

You beat me to it.

Technically, the diffraction limit is around f/11 because the effective f stop has increased by two stops at 1:1 magnification! However, based on my observations, I think diffraction doesn't become a major issue until somewhere between f/32 and f/22 for this setup.

[8x10 user]

The Apo Ronar is said to be diffraction limited at F/22. It would be interesting to see how one compares to the AMED at smaller apertures.