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Dallmeyer A.M. 14in 356mm f4 with handmade brass M42 adapter
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PostPosted: Sun Jun 20, 2010 11:09 am    Post subject: Dallmeyer A.M. 14in 356mm f4 with handmade brass M42 adapter Reply with quote
Here's something you don't see every day. Surprised

I went on a trip last weekend to the nearest city (300km / 4.5h drive), and while there, I was rummaging through a second hand store. Underneath some furniture and an old accordion(!), I discovered a huge lens with a very vintage & homemade looking brass M42 adapter. Shocked Shocked Shocked




The lens has a number of markings on it which, with the help of Google, have helped me get a rough idea of its origins:




Apparently the J.H.D. stamp and the UU serial number both signify that it is a design/product of the John Henry Dallmeyer company, while the A.M. and the arrow signify that it was built for the UK Air Ministry for use as an aerial photography lens, possibly in the WWII timeframe. Supposedly the "14A" is a design or category, while "3140" is the military contract under which the lens was produced.


The lens itself is quite heavy, and has a large aperture ring that stands out from the lens body. There is a brass block bolted to the ring, perhaps to couple the ring to a cable or some other mechanism? The lens mount threads are ~75mm in diameter, and the filter threads are the same.


The iris diaphragm has 20 blades, which completely disappear when wide open, and become reasonably small when stopped down. Several parts of the front lens ring, aperture ring, and lens body have been painted over and re-etched with different numbers, so I believe this lens started out as a "14in f/5.6", but has now been relabeled to "356mm f/4". The factory aperture markings seemed to have ranged from f/5.6 to f/16, while the hand-engraved numbers range from f/4 to f/11.




I held the lens up to the window with the curtains drawn around it, and by holding a piece of paper up behind it, the infinity focus point seems to be around 80mm behind the M42 flange of the adapter. Since neither the lens nor the adapter have provisions for focusing, my only conclusion is that this was designed to have a bellows or variable extension tube inserted between the adapter and a camera body.

Without the adapter, this lens has a huge image circle. Shocked Our estimates with the sheet of paper put it a bit short of two A4 lengths in diameter when focused at infinity... so something like 50cm? Shocked I could be wrong, but I think this puts it in "ultra large format" territory? Shocked


That's about all I know. Wink


PostPosted: Sun Jun 20, 2010 12:43 pm    Post subject: Reply with quote
Goodness gracious mercy sakes! Shocked


PostPosted: Sun Jun 20, 2010 2:42 pm    Post subject: Reply with quote
Stupendous find !

I think you are right about the focusing mechanism; and I would think that bellows were the original solution. Focusing tubes that I have seen rotate.


PostPosted: Sun Jun 20, 2010 5:59 pm    Post subject: Reply with quote
This is not a rare lens at all; for a number of years after WWII, both used and unused military equipment were sold by military surplus shops at very low prices, and there were no shortage of enthusiasts who purchased them, and modified them for various purposes.

It is obvious that a previous owner built a lens tube to fit its back and then used it as a long-focus lens; I feel sure that if a focussing mechanism can be improvised you should be able to use it as an extreme long focus lens, but it would be desirable to improvise a lens hood as well; the contrast should be quite low too.

When I was in the old country (UK) a few decades ago, these lenses turned up in significant quantities at the various photographic collectors fairs and they seldom got sold; I suppose now they are getting to be quite desirable!


PostPosted: Mon Jun 21, 2010 1:25 am    Post subject: Reply with quote
Hmm... I certainly haven't found large amounts of information, nor a single other Air Ministry lens like mine for sale... so perhaps many (most?) were scrapped, trashed, or broken apart for their lens elements?

The closest I have found is this Dallmeyer Anastigmat 14in/5.6 on ebay, which appears to be the civilian version of mine.
Click here to see on Ebay US $600. Shocked
ebay wrote:



I did a quick test with some extension tubes, and it seems as though the contrast isn't too bad actually. I will have to do some more thorough tests once I have a way to focus it. Wink

Good idea with the hood. Shouldn't be too hard to construct one that slip-fits over the end of the lens.


PostPosted: Mon Jun 21, 2010 2:00 am    Post subject: Reply with quote
I have a similar 14" WA Brown process lens. The image circle is at least 20" maybe 24" without vignetting! I couldn't see the entire circle in my too-small 14x18x18" test box. Beautiful wide-angle. f/8-90(!) Weighs at least 3kg probably more. Someday I hope to use it to expose 16x20" Provia or equivalent, and for contact prints. Cool

US Patent #3,263,562 "Four Element Symmetrical Reproduction Lens" Feb 6, 1963.


PostPosted: Mon Jun 21, 2010 4:50 am    Post subject: Reply with quote
Siriusdogstar,

Process lenses are a totally different type altogether: they are often of small aperture but optimised for low-power close-up work, with highest possible correction and flat field. The Dallmeyer shown by the OP is of regular construction, and many other aerial survey lenses are of different design again.


PostPosted: Mon Jun 21, 2010 6:48 am    Post subject: Reply with quote
Wow, what a find! Samples please! Laughing


PostPosted: Mon Jun 21, 2010 6:50 am    Post subject: Reply with quote
siriusdogstar wrote:
I have a similar 14" WA Brown process lens. The image circle is at least 20" maybe 24" without vignetting! I couldn't see the entire circle in my too-small 14x18x18" test box. Beautiful wide-angle. f/8-90(!) Weighs at least 3kg probably more.

f/90! Shocked

Do you have any pictures of yours? I would be interested to see how small the aperture is at that setting. I also found it interesting that mine does not stop down as far as the civilian Dallmeyer in the auction... but I had read in one place that the aerial photography lenses were designed to have limited adjustment ranges to eliminate the possibility of error by the operators. Sounds plausible to me.

Seele wrote:
Process lenses are a totally different type altogether: they are often of small aperture but optimised for low-power close-up work, with highest possible correction and flat field. The Dallmeyer shown by the OP is of regular construction, and many other aerial survey lenses are of different design again.

Seele- These are all new to me. Would a flat field lens still be usable for "normal" photography.. say something like landscape usage? Also, do you have any details on the different types of aerial lens designs?

Thanks. Cool


PostPosted: Mon Jun 21, 2010 7:04 am    Post subject: Reply with quote
Scheimpflug wrote:

Seele- These are all new to me. Would a flat field lens still be usable for "normal" photography.. say something like landscape usage? Also, do you have any details on the different types of aerial lens designs?

Thanks. Cool


Scheimpflug,

Some of the process lenses are indeed usable for general photography, although they tend to be small aperture, fully-symmetrical designs optimized for low-power magnifications. A popular lens for large format, or ultra-large format photographers, is the Goerz American Red Dot Artar, which are somehow modified for general photography if mounted in shutter.

Aerial lenses tend to be of comparatively wide angle designs, and for the allied forces during WWII they are generally meant to cover a 5"X5" format. The most famous would be the Aero-Ektar of very large aperture, but those by Ross for the British forces are quite common too, and after the war they were also made mounted in shutters for the civilian market but were sold in small quantities. The 5" is actually not at all scarce but I do have a Wide Angle Xpres 4" in Compur, which is of Plasmat construction. In fact it is the first modern Plasmat with departed from true symmetry, and the true forerunner of all the large format lenses of standard coverage, such as the Symmar-S (and successors), Sironar, etc.


PostPosted: Mon Jun 21, 2010 10:06 am    Post subject: Reply with quote
Fantastic find! Congratulations!


PostPosted: Mon Jun 21, 2010 2:03 pm    Post subject: Reply with quote
Seele wrote:
Siriusdogstar,

Process lenses are a totally different type altogether: they are often of small aperture but optimised for low-power close-up work, with highest possible correction and flat field. The Dallmeyer shown by the OP is of regular construction, and many other aerial survey lenses are of different design again.


Thank you for the infomations! Very Happy


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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