View Full Version : Separating the front two elements of a 14" f/5.6 Dallmeyer Serrac

17-May-2011, 09:27
I recently purchased an Air Ministry f/5.6 14" Dallmeyer Serrac (JHD 10 on the lens body, contract 14A/3140) at a flea market.

There's substantial haze, probably from oil on the aperture blades. I was able to remove the front and rear cells for cleaning and the rear elements cleaned up nicely, but I'm not sure how the front cell separates (it's a Tessar formula, so there is air between the front two elements).

Searches tell me a few folks on this forum have taken this lens apart, anyone have any ideas?


Dan Dozer
17-May-2011, 16:54
Hi Jason,

The front element does unscrew - it separates just behind the ring that has the threads that screw it into the barrel. If your lens is the same as mine (mine is not the Air Ministry version), the ring just behind the one with the barrel threads has some tiny knurling on it. The joint that separates the two halves is just between the threads and the knurled ring.

Now, there is also a very tiny hole in the edge of the ring that has the barrel threads on it. There isn't anything in that hole on my version, but yours might have a very tiny screw in that you might need to remove or loosen in order to unscrew the two halves.

Hope my description and photos show what I'm talking about and help you.


17-May-2011, 18:21

I took a swing at separating it that way the other day, but I totally missed that tiny, tiny hole. I'm going to have to track down an eyeglasses repair kit to get that screw (which is present on my lens).

Thanks so much, I'll let you know how it turns out.


17-May-2011, 19:00
I was able to get it with a paring knife! Thanks again.

Now I just need to find the right camera to pin it on.


Dan Dozer
18-May-2011, 12:59

I used mine previously on my 8 x 10 Kodak 2D and now on the Deardorf. However, as you know, it is rather heavy so it needs a sturdy camera. You'll find that the image circle on this lens is likely to be larger than expected. I've used mine at portrait distance on my 8 x 20 camera. However, it easily covers 8 x 10 at infinity with lots of movement.

The version I have is strange in that it goes from F4.5 only down to F11. Your's is the F5.6 version and I've heard others who are different still. Mine also has a lever on the aperature ring for adjusting the aperature (most others I've seen don't have the lever). I assume that mine was designed for aerial photography (which many were), which may be why it only goes down to F11. However, mine is the Dallmeyer version, not the Air Ministry version. Maybe that only means that it wasn't intended to be sold in Britain.