Schneider Kreuznach D-Claron 3.5/40

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oskar

Not sure but I think the D is for document.

These are micofilm lenses. Before cheap computer memory they were storing newspapers and such on 16mm film or more likely reading the microfilm.

[ChrisR]

B - Yes that one's too expensive. I'd be surprised if the usual suppliers in HK etc don't have some in stock, though. When those lenses were in popular use, I'd bet half at least were used with a 39mm adapter. How often do you see an enlarger with a 25mm hole?

[ChrisLilley]

Not sure but I think the D is for document.

These are micofilm lenses. Before cheap computer memory they were storing newspapers and such on 16mm film or more likely reading the microfilm.

Aparenly so - see http://en.wikipedia.org/wiki/Schneider_ ... h#D-Claron

"The D-Claron (Dokumentations-Claron) is a lens family designed for copying of documents onto microfilm."

[Oskar O]

Aparenly so - see http://en.wikipedia.org/wiki/Schneider_ ... h#D-Claron

"The D-Claron (Dokumentations-Claron) is a lens family designed for copying of documents onto microfilm."

I stand corrected, although was right about the application. The lens should have good potential.

As for 25->39 adapters, since they are essentially relics from the wet darkroom era, I guess camera stores and such may have some laying around, may even give for free or almost nothing if asked. Jam nuts and such often come as part of auctions when buying a lens, so people may not bother separately listing these sorts of adapters due to their low demand and value.

[Blame]

Well right now I am using my mitutoyo adapter. It is not the right size or thread but padding out with sellotape gave a very successful fit. I know it is good because the vignetting is symmetrical. For use with with camera lenses which don't have a recessed front lens I am padding it out with 2 52mm filters with glass removed.

I am thinking of getting a cheap ebay 25-28mm ebay adapter and seing if it can also be bodged to fit. Also a 28-52mm. From 52mm the choice is wide open and I already have lots. It is no use selling off cheap objectives if the adapter costs more than the objective. There has to be a sensible solution.

I won't try the 135mm just yet as it won't define the limits. Instead tomorrow I plan to try with my 70mm sigma macro. I know it will vignette but I trust the sigma. It should give a true limit to the field of view and sharpness.

This is interesting stuff. I don't know of any other attempts to use a enlarger type lens with a tube lens. Logic says it should be best. An objective should give best sharpness when all the good available field of view is used AND it is operating with front & back focal lengths as optimized. Most enlarger lenses improve as back focal length increases to the limits of the manufacturers data - it follows that they should be good at infinite back focal length. The questions are is my logic good, and is the improved quality sufficient to make up for losses in the tube lens?

Edited - to correct silly mistake. I hope to use the Claron with a tube lens - not as a tube lens.

[Craig Gerard]

This is interesting stuff. I don't know of any other atempts to use a enlarger type lens as a tube lens

A few members have been using Rodenstock Apo-Gerogon lenses in combination with a bellows or some other form of adjustable extension.



http://www.photomacrography.net/forum/v ... hp?t=12483




Craig

[ChrisR]

I don't know of any other atempts to use a enlarger type lens as a tube lens. Logic says it should be best.

Several of us have tried repro lenses as tube lenses I think. Charlie was first with his Nikkor. The requirements of the tube lens don't seem to be too difficult - the "morfanon" isn't a very good lens!

But there seems to be confusion in your suggestion, between
Using an enlarger type lens as a tube lens
and
Using an enlarger type lens with a tube lens .

The logic to me says "as" a tube lens would NOT be best, because they aren't designed to to have either focus at infinity. An ordinary telephoto/"Long" lens, IS.
They aren't ideal as front end/short FL lenses (on a tube lens) either, for the same reason. Ordinary 50mm standard lenses work pretty well when reversed on the front of a long lens because the rays in between the two are to and from infinity.
An enlarger/copy lens doesn't fit "correctly" at all. It may be a less bad fit than using it simply on extension, depending what magnification you're trying to get. "We" simply can't use this lens with ray-paths near where the designers intended. How much it matters, and which direction of deviation gives less problems, it'll be interesting to see.

As far as I can remember, nobody has used the little JML lenses on a tube lens. They might be good, but they aren't bad on bellows!

Diffraction: Just to spell it out, and get it clear in my own head, (correct me if I'm wrong,)
The 24x quoted is actually a reduction by 24x.
We are interested in using the lenses for magnification.
When you use it as a reducing lens, sensor side effective aperture is
3.5 *(1+1/24) = 3.54 approx, = not a problem.
When it's magnifying by M, effective sensor side aperture is
3.5 * (M+1) (= BAD, with M approaching double figures.)

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Chris

My bad. I should have said "with a tube lens".

Enlarger type lenses are rarely going to be used quite as designed for photomacrography. The D-claron's won't be. 24x would give rotten results. In theory they are NA 0.14 which should give a resolution of 2um (subject side). At 24x that would give a resolution of 48um but frankly I would be amazed if it got close. Pixel size is about 5-6um for the sorts of cameras we use. A magnification of 2.5x gives 5um in theory (and hopefully not that much worse in practice) which would be a much better fit.

They were as you say not designed to be focused at infinity. Catch is, they were not designed to focus at, say, 140mm ether - which should give a magnification of 2.5x on their own.

I think that moving from a focal length of about 1000mm to infinity is less of a shift from design that moving down to 140mm, on the grounds that a move of 1 diopter is less than about 6, but I could be wrong. Soon I will have more evidence.

I think reduction Vs enlargement is a non-issue. Lenses don't care which direction the light travels so why should we? The important point is that for magnification they needs be pointed with fat end towards the camera.

The field of view is going to be something like 20mm (subject side) or 20mmXmagnification (sensor side) but when used outside it's intended spec's who knows? It probably wont be that far away.

[ChrisR]

The Componons and EL-Nikkors are 6 elements in 4 groups, "optimized for 2×-20× enlargements".

I think reduction Vs enlargement is a non-issue.

Nobody said it wasn't, apart from Diffraction!

[Blame]

Ok - made quick test with my sigma 70/2.8 macro. A lens to put faith in.

Field of view is not as pretty as the manufacturers specs led me to believe. 19mm tops. About 16mm with 2 stops vignetting. Bottom line is that the sigma 70/2.8 would make a perfect tube lens with a cropped sensor camera like a canon 600D but a Full frame camera needs 100mm or more.

I am trying to remember the results of my mitutoyo 5x. I think the coverage was about as even with 140mm tube lens as the 3.5/40 should be at 100mm.

Cool. I can cover the range from 2.5x to 10x.

2.5x...schneider 3.5/40 with 100mm lens........Na 0.14..F/8.8....14.4x9.6mm
3.5x ..mitutoyo 5x with 140mm (nominal 135)..Na 0.14..F/12.5..10.3x6.9mm
5.0x...mitutoyo 5x with 200mm lens...............Na 0.14..F/17.5..7.2x4.8mm
7.0x...mitutoyo 10x with 140mm (nominal 135).Na 0.28..F/12.5..5.5x3.4mm
10x....mitutoyo 10x with 200mm lens..............Na 0.28..F/17.5..3.6x2.4mm

Ok, no time till about tuesday but then I plan the big one... A direct comparison with the mitutoyo 5x at 3.5x magnification.