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Dallmeyer A.M. 14in 356mm f4 with handmade brass M42 adapter
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PostPosted: Fri Jun 25, 2010 10:13 pm    Post subject: Reply with quote
Here's the W.A. Brown 14" Process lens (couldn't find my little metal rule, hmmmm):





1:4 macro of aperture set to f/22:



1:4 macro of aperture set to tiny f/90 (surprise! a second set of leaves Shocked ):



(5D1 + M42 Asahi Macro-Takumar 4/50)

The only info I've found about the lens is in the patent; the number conveniently engraved on lens Smile : US Patent #3,263,562 "Four Element Symmetrical Reproduction Lens" Feb 6, 1963.


PostPosted: Sat Jun 26, 2010 1:29 am    Post subject: Reply with quote
Now thats a lens !

I may have seen a similar double-diaphragm before if I remember correctly, but I don't recall what it was in. Its certainly an unusual feature.


PostPosted: Sat Jun 26, 2010 3:10 am    Post subject: Reply with quote
wow


PostPosted: Sat Jun 26, 2010 3:03 pm    Post subject: Reply with quote
ManualFocus-G wrote:
Wow, what a find! Samples please! Laughing


I'm working on it. Very Happy

Before I can really use the lens, I first need to solve this problem:
http://forum.mflenses.com/supporting-bellows-with-heavy-lenses-t29415.html ("Supporting bellows with heavy lenses?")
That is, how to effectively get the thing into a usable, focusable assembly. I can temporarily bypass this dilemma by using lightweight fixed length extension tubes, but the tubes I have give me three options: a bit past infinity, "close", and "really close". Wink I thought about using the "close" setting and doing some "focus with your feet" test shots, but considering that this is pretty much a tripod-only lens, it isn't really practical. I have a few handheld shots, but they definitely don't do the lens justice. Embarassed

Secondly, I need to order a thinner M42-to-Nikon adapter, as my first choice (a Nikon T-mount adapter with the M42x0.75 insert replaced with a M42x1.0 insert) will be too thick with a bellows in place (I wouldn't be able to hit infinity focus). I had initially selected this M42-Nikon adaption method to allow rotation, as the tripod mount on this lens is welded in place (can't be rotated), and I wanted the ability to rotate the camera body relative to the lens to align things. I suppose now I will have to get a "thin" (standard thickness) adapter and just see where the alignment falls. Neutral


In the mean time, I made a parallel thread over at the Large Format Photography Forum, and have received some interesting responses about the lens type and the possible cameras that could have used it. You can read more at this thread:
http://www.largeformatphotography.info/forum/showthread.php?t=63693


PostPosted: Sat Jun 26, 2010 7:00 pm    Post subject: Reply with quote
luisalegria wrote:
I may have seen a similar double-diaphragm before if I remember correctly, but I don't recall what it was in. Its certainly an unusual feature.


Jupiter-6 and Helios-40 have this kind of diaphragms, as far as I remember. I have no idea why.


PostPosted: Sat Jun 26, 2010 8:03 pm    Post subject: Reply with quote
Use plastic plumbing pipe, get two sections that fit one inside the other for focusing, cut slots use bolts & wing nuts, you get the picture...just like a homemade telescope, camera instead of eyepiece. Flock or paint interior reflective surfaces inside tube.
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