Dallmeyer A.M. 14in 356mm f4 with handmade brass M42 adapter

[Scheimpflug]

Hello! I'm new to both this forum and to large format photography, but I have a new lens and figured this would be the place to learn about it.


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.



The lens has a number of markings on it which, with the help of Google (many of the search results ending up here), 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. 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? I could be wrong, but I think this puts it in "ultra large format" territory?

That's about all I know. Like I said, I'm completely new, so please correct me if anything is incorrect, and let me know if you have any other insight into what this lens was designed for, or what it could be used for.

Thanks!

[Scheimpflug]

Here's a second set of pictures, that couldn't be included with the first post due to the 4 picture limit...

[Pete Watkins]

You've pretty much got it all right. I believe that the 14A means that it's a contract for photographic equipment and 3140 is , as you state, the contract number. WW2 is also correct. Quality has been known to vary.
Have fun with it.
Pete.

[Scheimpflug]

Thanks.

Are there any guides to Dallmeyer serial numbers that would cover this time period to get a more accurate age estimate? The ones I have found only seem to cover up through 1900. (example: http://web.archive.org/web/200612220...colucci/sn.htm)

Also, does 75mm sound correct as a mount diameter, and does that match any "standard" large format or ultra large format sizes? After seeing the image this lens made on the paper, I'm tempted to pick up a flange and build a camera around it.

It also seems that the reports of varying quality in these Air Ministry lenses seem to vary by manufacturer.. most of the UU/JHD identified posts that I've found seem to indicate that they found the lenses to be of better quality. But this is just what I've gathered by searching, and I'm probably a bit biased.

[Steven Tribe]

This is one of the contract numbers (3140) which isn't listed in VM. They talk about a "no name" Dallmeyer Air Ministry objective at F5.6 and 14" which they think might be a Serrac. I don't think the real coverage will be that large - the F4.5 14" Serrac civilian version covers about 8x10". It is described as a Tessar design - so the coverage would be similar to a IIb Tessar perhaps - which for 14" is also described as 8x10.

[Dan Fromm]

It is an aerial camera lens. The large UK-made aerial cameras of its time shot 9"x9" on 10" roll film. These cameras were not hand-held, were attached to cradles that were attached to the aircraft. Everything bolted together as securely as possible.

Lenses for most aerial cameras -- there are a few exceptions -- were mounted on what are called lens cones. The cone in turn attached to the camera body. The lenses were collimated to the camera -- focused to infinity by moving the lens fore/aft in the cone -- and locked into the cone. That's why there's no provision for focusing. Not directly relevant, but I've had a couple of TTH 12"/4 telephotos for the AGI F-139, a hand-held (sometimes) camera that shot 6x6 on 70 mm film; both showed signs of repeated re-collimation.

I've handled an example of your lens. Tessar, and no doubt about it. I don't know why the aperture scale was re-engraved, this makes no sense unless the diaphragm was reworked to open wider. This may have required no more than removing a stop, but since I've never opened one up I don't know if this is the case.

[Scheimpflug]

Steven-
What is VM, and what is a Serrac?

Dan-
9"x9" is pretty big, but still seems like only a small percentage (maybe 25%?) of the image produced by this lens. Is there any particular reason why they would have made the lenses so large if they could have reduced the view and made them smaller/lighter?

You wouldn't happen to have any photos of the one you handled, or of the assembled cameras in the aircraft, would you?

I don't know if the diaphragm was reworked on mine or not, but I can say one thing with absolute certainty- there is no way it could open up any further! When set to the hand-engraved "f4", the blades are fully retracted into the side of the lens barrel. Not a single bit of the blades are left exposed in the light path. I do not know if this is normal?

In my two photos above that look through the lens, the first is wide open (f4), and the second is fully stopped down (f11). So those are the two extremes of the aperture adjustment.


Thanks for the replies!

[cdholden]

Dan,
I'm curious about the "repeated re-collimation". Do you know if this was due to reusing the lenses through a course of camera changes/upgrades? Or maybe cameras being adjusted to meet focus/calibration spec in the preventive maintenance routine on the aircraft?

Chris

[jb7]

I recently bought a 36" f/6.3, and did some research-

I think this page might be useful-
according to the numbers, it seems your lens might have been matched to an F.52 camera ...


http://www.airrecce.co.uk/cameras/raf_ww2_cameras.html

[Dan Dozer]

I also have a 14" Dallmeyer Serrac. Serrac is the name of this series of lenses that Dallmeyer made. It has all the information on it that makes it appear to be the commercial version, but the F-stop range is only from F4.5 - F11 so I'm assuming that it is the Air Ministry type used for Aerial photography as others have suggested. The lens looks very similar to yours without the huge extension piece that yours has. There is a pretty good chance that your lens is also a Serrac.

Without getting into the complicated terms of glass/lens types, the lens has a lens element on the front and back of the lens, but not in the middle. I believe that this is what a "tessar type" is, but others who know much more about this can respond to that.

The lens that I have has much more coverage than what others may be saying. I've used it for full length portraits on my 8 x 20 camera. Comparing it the a lens like a Voighlander Heliar (on the outside, they look very similar) for example, this lens has an image circle much larger than the 360 MM Heliar. Note that the Heliar has three lens groups not two so it is a much different lens type.

From what the Vada Mecum mentions - there is a little info noted, but not a whole lot. One thing that it does say is "An especial claim was that the rear glass was about the same diameter as the front giving more even illumination and that while flair was kept to a minimum, there was a generous coverage for the use of rising fronts". They are noted as both pre and post war and post war versions might be coated.

I haven't really used my Serrac very much so I can't really say a lot about the performance. I think that this is a lens type that not many people have much experience with. It might be one that photographers with ultra large format cameras (larger than 8 x 10) might be interested in because of the coverage.

Hope this helps.