Wonderful "new" source for flat-field macro lenses

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Norm Dresner - 23 Dec 2005 15:52 GMT

I recently purchased on eBay a Componon-S enlarging lens with the idea that
I'd fit it to the bellows of my 2-1/4" sq camera as a flat field macro lens.
While cleaning off a shelf I came across a T-mount for my Nikons and
discovered that the enlarging lens' thread matches perfectly the inner
thread of the T-mount. This means that any really good enlarging lens with
standard thread can be mated with a T-mount for "any" 35mm camera and put on
a bellows or extension tube to function as -- perhaps -- one of the finest
flat field copy/macro lenses available.

Norm

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David Littlewood - 23 Dec 2005 16:23 GMT

>I recently purchased on eBay a Componon-S enlarging lens with the idea
>that I'd fit it to the bellows of my 2-1/4" sq camera as a flat field
[quoted text clipped - 6 lines]
>
> Norm

Hi Norm

It's just possible that the Componon will work better for high
magnification if reversed - then the optics will be working at something
like the cojugates it was designed for. Of course, if it is a
symmetrical design, it may not make that much difference.

My 50/2.8 and 100/5.6 Componons both have 43mm filter threads on the
outside, so an adapter ring should be possible. The stop down lever
might get in the way though.

I haven't tried this with mine - I have numerous other purpose-built
macro lenses already.

David

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David Littlewood

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Malcolm Stewart - 23 Dec 2005 17:25 GMT

> I recently purchased on eBay a Componon-S enlarging lens with the idea that
> I'd fit it to the bellows of my 2-1/4" sq camera as a flat field macro lens.
[quoted text clipped - 6 lines]
>
> Norm

And what is the colour rendering like ?
I tried this years ago, but the huge difference between the colour from my
Minolta camera lenses, and the 50mm f2.8 CE Rokkor enlarging lens meant that
my results were only OK if I was using B&W. (This was before Photoshop...)

Signature

M Stewart
Milton Keynes, UK
http://www.megalith.freeserve.co.uk/oddimage.htm

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Norm Dresner - 24 Dec 2005 21:02 GMT

>> I recently purchased on eBay a Componon-S enlarging lens with the idea
> that
[quoted text clipped - 17 lines]
> that
> my results were only OK if I was using B&W. (This was before Photoshop...)

I haven't tried using the lens yet, but should be able to get to it in the
week between the holidays [How's that for PC mealymouthing to avoid using
the word "Christmas"??? I apologize! <LOL>]

Norm

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bjw@mambo.ucolick.org - 31 Dec 2005 03:56 GMT

> I recently purchased on eBay a Componon-S enlarging lens with the idea that
> I'd fit it to the bellows of my 2-1/4" sq camera as a flat field macro lens.
[quoted text clipped - 4 lines]
> a bellows or extension tube to function as -- perhaps -- one of the finest
> flat field copy/macro lenses available.

I'm assuming you mean a normal T mount that fits on the camera
body and has a female thread to take T-accessories (lenses,
telescope adaptors, etc). I'm surprised you can screw your enlarging
lens into one, because the thread specs are different. The T-thread is
42 x 0.75mm; recent Componon-S lenses in the 80-100mm range
are Leica thread (39mm,26tpi), older ones are 25mm, and bigger
ones are 50mm.

I looked at a couple of T mounts and both had an inner thread behind
the main thread, but neither was Leica thread, just some random
threading the manufacturer put on to reduce reflections. Also it was
impossible to actually fit the lens that far back into the mount.
While it's great that you heve something that fits, be aware it may not
work on the next T adapter you come across. That said, the basic
idea of putting an enlarger lens on bellows is good; some makers
may have made adapters, plus there's always the official method,
namely gaffer taping a lensboard to the front of the bellows.

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Norm Dresner - 31 Dec 2005 21:49 GMT

>> I recently purchased on eBay a Componon-S enlarging lens with the idea
>> that
[quoted text clipped - 27 lines]
> may have made adapters, plus there's always the official method,
> namely gaffer taping a lensboard to the front of the bellows.

I guess I wasn't looking all that closely when I discovered the match but
since you've mentioned it, I did some more research. I went to the
Schneider website and downloaded the spec sheet for the lens (135mm f/5.6)
which includes a detailed drawing of the lens at
http://www.schneideroptics.com/photography/photo_enlarging/componon-s/pdf/compon
on-s_56_135.pdf.

The lens that I have seems to conform to that drawing as closely as I can
measure it with an inch-based dial caliper EXCEPT that the drawing calls for
a thread of 50mm x .75mm and the lens I have clearly has a thread that's
significantly smaller! In fact it's 1.647" diameter which corresponds to
42mm (actually 41.83 but that's close enough to 42mm for me -- and to the
T-mount adapter too).

AFAICT, this is a perfectly normal T-mount adapter designed to take a 42mm
thread.

SO ... the question is, why does this seemingly normal Componon-S lens have
a 42mm thread where it should have a 50mm thread?

The (non)answer, of course, is, "I don't know!"

If anyone has more information that will shed light on this mystery we'd
(all) be grateful.

Norm

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