It looks almost exactly like a spiratone enlarging lens that I have. Mine works reasonably as a bellows lens when reversed. Not as good as a nice 35mm bellows lens, but not bad for $5.

It is the best discussion of DOF that I have come across. I haven't waded through the whole thing yet, but it seems very interesting. It's a big read.

http://www.zeiss.com/C12567A8003B8B6F/E ... keh_en.pdf

I see this kind of flare issue with quite a few lenses when shooting a glass slide using reflected light. A dark piece of cloth over the front of the slide often helps. Also helps to back the light off a bit.

I have one of those. The WD is about 6 mm. Mine doesn't perform significantly better than my M Plan 10/0.25

I have a resolution tester out there like your smoked glass. It's a proof silver american eagle (mirrored fields). I was trying to clean a couple pieces of dust off of it for photography and used some canned air. Got the blast a little close and spattered the coin with the propellant. Ruined the coi...

Looks like the working distance is 5.6 mm. not ideal but workable for the stuff I do.

Working distance?

I have an Edmunds 10/0.25 (one of the cheap ones, not Nikon). It performs virtually as well as my Nikon Mplan 10/0.25. The biggest limitation is that it has about 1.5 mm of working distance.

The lenses where you can really see the improvement with reversing are the shorter focal length ones, say 50 mm or less.

My 50/2.8 has a 43mm ring

The rest are either 40.5 or 30.5

Normally mounted, the 55/2.8 gives you 1.43:1 with 50 mm of extension.

It only focuses to 1:2. It's one of the older MF ones.

All that I listed are reversed. No extension unless specified.

this link.

http://www.photomacrography.net/forum/v ... php?t=8336

The mag that you get varies with the lens. how far back are the elements from the front, how long is the lens?

55/2.8 micro - 0.9:1
50/1.4 - 0.97:1
El-nikkor 50/2.8 - 0.54:1

55/2.8 with 50 mm extension - 1.8:1

Thinking back to Rik's posting re: coupled lenses showing how the position of the aperture changes the path of the light through the lens (he linked to it in a recent post). You have changed the position of the limiting aperture of the lens by adding the aperture on the back and are probably inducin...

Rik. thanks for the link to the lens combo discussion. I never saw that the first time.