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04-26-2014, 04:25 AM   #1
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How to Reverse an Enlarger Lens (PLEASE HELP)

Hello everyone. Can someone help me how to reverse an enlarger lens? (for macro work)
I am planning to get a Vega 11U 50/2.8 and shoot some deep stack photos with it. There is no info what thread size this lens has.
What i mostly read is using step-up ring etc... Can someone help

04-26-2014, 04:41 AM   #2
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Are you using Pentax K bellows?
Google indicates Vega 11U 50/2.8 may be M39 Leica mount?
Nose has no thread, just a smooth ring ?

I adapted a similar Rodenstock for reverse mount into Pentax bellows and did it by machining a threaded aluminum adaptor ring for M39, and a press fit adaptor for the nose, out of soft acetal.

You might be able to buy a K to M39 adaptor, but I think the nose adaptor might need to be custom.
04-26-2014, 04:57 AM   #3
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thats my problem right there... i guess ill have to find an el-nikkor 50/2.5 at a great price
04-26-2014, 05:06 PM   #4
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QuoteOriginally posted by wombat2go Quote
Google indicates Vega 11U 50/2.8 may be M39 Leica mount?
Almost all enlarger lenses are nominally M39 (LTM).


Steve

04-26-2014, 05:51 PM   #5
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QuoteOriginally posted by stevebrot Quote
Almost all enlarger lenses are nominally M39 (LTM).
And it must be one of the weirdest threads in history.
Metric diametral dimensions of 39 mm OD yet 26 turns per inch and of the obsolete Whitworth form needing a 55 degree tool all the way from UK.

Well I am just working on adaptors for an old Ilex lens.
On the same barrel, one end thread is the Ilex 1.771 inch by 50 turns per inch, and the other end is a 50 mm by 0.75 mm pitch !

After the 1960's USA was the last country to use inch threads, fortunately the USA threads are of similar form
(60 degrees, equilateral, makes the calculations easier) to metric except for the inch dimensions.
Also fortunately there is a prime number (127) that lets us make both inch and metric camera threads on the same lathe.
04-26-2014, 07:26 PM   #6
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QuoteOriginally posted by wombat2go Quote
And it must be one of the weirdest threads in history.
Metric diametral dimensions of 39 mm OD yet 26 turns per inch and of the obsolete Whitworth form needing a 55 degree tool all the way from UK.
Blame the good folk in Wetzlar. IIRC, there is a story behind the mix of metric and English standards.


Steve
04-26-2014, 08:53 PM   #7
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Thanks for the replies...i just purchased an el~nikkor 50/2.8N to save me the hassld...
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