Enlarger lens comparisons

[Martin Rickards]

How useful are enlarger lens comparisons when used reversed as macro lenses? It seems that many lenses that are happily used for enlarging fare rather poorly in such comparisons whereas virtually unknown lenses fare far better.

 

[ic-racer]

I have not seen any posts of enlarging lenses giving poor results with macro photography.

 

[Martin Rickards]

For example: https://www.closeuphotography.com/tominon-e36-lens/2019/9/1/tominon-e36-c-48mm-f4-lens

 

[AgX]

You can take over the ranking from those comparisons, as the rays cannot differ between left and right.

 

[Martin Rickards]

You can take over the ranking from those comparisons, as the rays cannot differ between left and right.

Sorry, I don't understand "You can take over the ranking"

 

[AgX]

I assumed that with "lens comparison" you actually meant a ranking in image quality. Something that repeatedly came up here at Apug.
Furthermore, following the laws of optics, you can take over such ranking for exchanged subject and camera postion.

 

[Martin Rickards]

I assumed that with "lens comparison" you actually meant a ranking in image quality. Something that repeatedly came up here at Apug.
Furthermore, following the laws of optics, you can take over such ranking for exchanged subject and camera postion.

Yes, I was referring to image quality. I guess what you are saying is that that optically the object and its image can be transposed so that these comparisons are valid. Hence the Tomioka Tominon represents a quantum leap in IQ when compared with a Componon-S 50 mm f2.8, which I understood to be one of the very best lenses for 35 mm negatives or even the Leitz Photar 50 mm f4.0 macro lens.

 

[AgX]

Exactly. If you twist the lens, thus exchange the position of subject and film, the moment the ratio between subject and film distance turnes around, optically nothing has changes.

However... enlarger lenses of the Double Gauss type (e.g. Componon) are nearly symmetrically built, more so than taking lenses designed for much larger subject/image size ratios. Thus I very much doubt that with enlarger lenses twisting would make sense at all. Moreover I have not come across a hint in that direction in literature.

 

[reddesert]

For example: https://www.closeuphotography.com/tominon-e36-lens/2019/9/1/tominon-e36-c-48mm-f4-lens

In this test, the closeup author reverses an enlarger lens and takes a magnification 2.6 image onto an APS-C sensor, meaning he images a 6x9mm target onto a 16x24mm sensor. Actually, he takes a series of images stepping the focus, and the lens is set to f/4.5 meaning the effective aperture is f/16 (and diffraction limits the ultimate image quality).

Optically, yes this is basically analogous to enlarging from a 6x9mm negative onto a 16x24mm print, as AgX says, the light doesn't care which way it is going.

Practically, I don't think rankings in these tests are terribly determinative for a common enlarging use like making an 8x10" print from a 35mm negative. The author is trying to achieve a resolution on-sensor that is higher than any normal person can see on a paper print. In actual enlarging use, issues like field flatness (the lens, but probably more important the negative and the enlarger alignment) will affect the resolution, since the 35mm negative is much larger and less rigid than the 6x9mm target.

 

[runswithsizzers]

You might want to look at some of the Macro Lens Tests on <http://coinimaging.com/Lens_tests.html> The test results include enlarging lenses, macro lenses, bellows lenses, and repro (copy) lenses, and each lens is tested at several different magnifications.

That same set of web pages has a tool called "Lens Testing Hall of Fame" <link here> You enter can the magnification you plan to work at, and the tool lists all the lenses he has tested, ranked by performance at that magnification.

 

[AgX]

Interesting site. And indeed, he hints at reversing an enlarger lens.

The OP just may try it both ways...