A.M ?? 14inch f5.6

[camerasteve]

i've had alook in the vademecum but cant find any manufacturers with the initials a.m. anyone heard of them?
its a pretty big lens. in aluminium (thats what we call it here) the front of the barrell is 84mm across. it has a 20 blade aperture. non coated
engraved on the side is - a.m . 14a / 3140
serial no. is - uu278196

[Jan Pedersen]

The AM Engraving means Air Ministry. Many of these lenses were made under license for the Air Ministry in the UK during WW II and perhaps before.
The lens design is a triplet originally made by Dallmeyer who named them Pentac.
The demand was so high that Dallmeyer contracted other companies to make these lenses and those don't show the name of the company just AM.
Lenses where used for Aerial photograhy. The 14" is more rare than the 8" 2.9 of which i have one, a late Dallmeyer now monuted in a #5 Alphax great wide open and quite sharp stopped down. Some of the AM lenses did not quite perform as the Dallmeyers but you could have one of the better, go shoot some photos and have fun.

[Dan Fromm]

Jan, odds are that it is a 14"/5.6 Dallmeyer Serrac (tessar type) in Air Ministry dress. The contract number (3140) is not the one (3254) under which TTH made 14"/5.6 Aviars for the Air Ministry. According to the Vade Mecum, "UU" is the code for Dallmeyer. I've seen, didn't buy, a 14"/5.6 Serrac, own a 14"/5.6 Aviar.

It can't be a Pentac, Pentacs are f/2.9 and the OP's lens is f/5.6.

And Pentacs aren't triplets, they are heliar types.

Steve, there's an easy way to tell a tessar (Serrac) from a heliar (Aviar). Count reflections from a single light source. A tessar will have four strong, no weak reflections from the front cell and two strong, one weak, from the rear cell. A heliar will have four strong, one weak from one (usually the front) cell and two strong, one weak, from the other (usually the rear). Ole, I know that heliars are supposed to have the central singlet in front of the diaphragm, but I have an Apo Saphir with the central singlet behind the diaphragm (I identify the rear cell as the one that has no engraving on the trim ring, the front has the one that has engraving on the trim ring).

An air-glass interfaces produce a strong reflection. A glass-cement-glass interface produces a weak reflection, and weak reflections can be hard to see.

Cheers,

Dan

[Jan Pedersen]

Dan, Thanks for the correction. The 5.6 should off course be enough to tell that it isn't a Pentac. Lesson, no advice until after the first two cups of coffee.
Is it correct that a triplet has two strong reflections from the front and one strong from the rear?

[Jim Galli]

Dan, My Cooke made Aviar's are dialyt type. And well loved.

[Dan Fromm]

Jim, thanks for the correction. I blew it. Its the Pentac that's a heliar type. Ouch!

Jan, I've had my coffee already. Two cups, in fact. No such excuse for me.

About reflections. Each air-glass interface makes a reflection. One singlet, two reflections. Two singlets, four reflections. That's why coated lenses transmitted light better than uncoated ones.

[Jan Pedersen]

Jim, thanks for the correction. I blew it. Its the Pentac that's a heliar type. Ouch!

Dan, more coffee. You did write that the Pentac was a Heliar type first.

[camerasteve]

thanks a lot guys for the advice. i never even thought of the air ministry. it does seen to be a tessar type - 3 reflections from the back. 4 from the front.
the vademecum seems to be a bit ambiguouse. it mentions a no name 14" f5.6 but above this it says "serial no.s begin with uu or vv if original dalmeyer. does anyone one know if both prefixes are dalmeyer factory, or just the vv.

[Dan Fromm]

both

[Ole Tjugen]

WWII Aerial photography lenses were very much in demand at the time, and are quite often very poorly documented. They were military secrets as well, which made the documentation even better hidden.

There were also a bewildering number of different types: If anyone knows anything about a Schneider Göttingen Aerotar 30cm f:5.5 except for the fact that I own one, I would be glad for any information.

BTW - it seems to be a 3-3-2 Heliar derivative with a negative triplet in the middle!

[Paul Ewins]

I've got a 20 inch f/5.6 AM lens, serial 276999. It's marked "anastigmat" so I'm guessing it's nothing too exotic apart from it's size. The only other marking is "14A/227" which must be the contract number if that info was usually marked on the lenses.

I've also got an AM 8"/2.9 which has the marking "14A/780" on the barrel and a serial number of 406355. Interestingly it also has an indistinct mark that looks like it was rubber stamped on with white paint. The mark is a circle with "J.H.D." in the top half and "10" below which would imply that it had seen the inside of the Dallmeyer factory.

[Dan Fromm]

Paul, y'r 8"/2.9 should be a Pentac. Y'r 20"/5.6 might be an Aviar (dialyte type). Count reflections and then you'll know. The VM says that the 20"/5.6 Aviar is good, especially below f/7 or so.

[Paul Ewins]

Hi Dan, thanks for the info. The 20" is sitting on the Kodak 1A waiting for a chance to show its stuff. Once you have something that takes 9" lensboards no lens looks too big to use :-)

[Jim Galli]

Hi Dan, thanks for the info. The 20" is sitting on the Kodak 1A waiting for a chance to show its stuff. Once you have something that takes 9" lensboards no lens looks too big to use :-)

I LOVE the look I get with a 14" AM f5.6 Aviar wide open. I can only imagine the miniscule depth of field that a 20" must have. Here're a couple of shots from the 14 at wide open.


http://tonopahpictures.0catch.com/WhiteCoffeeCuo.jpg
coffee cup

http://tonopahpictures.0catch.com/ElevationWheel.jpg
elevation wheel

[misok]

Hi,

this is my first post on this great forum.
I'd like to ask about the lens this thread is about, because that's what i've recently bought on ebay and now i'm waiting for it. It's the very beginning of my LF journey and i'm very excited about it. My plan is to build a LF camera that will be using primarily 18x24cm paper negatives. Initially my rough guess was that if it has a focal length that is greater than needed image circle so it could be ok .. then I've read this lens is made to cover 5x5'' (which wouldn't be sufficient), then i saw nice Jim Galli's examples where i don't know what is the film size ... it's clear to me that i have to make my own tests but i'd like to know something about the image circle in advance.. so if anybody knew something .. i'd be glad.

all the best,

m.

[Jim Galli]

Those were done on 8X10 but as you see focus was near. I think the lens would cover 10X8 nicely at infinity, perhaps even 12X10. Jim


Hi,

this is my first post on this great forum.
I'd like to ask about the lens this thread is about, because that's what i've recently bought on ebay and now i'm waiting for it. It's the very beginning of my LF journey and i'm very excited about it. My plan is to build a LF camera that will be using primarily 18x24cm paper negatives. Initially my rough guess was that if it has a focal length that is greater than needed image circle so it could be ok .. then I've read this lens is made to cover 5x5'' (which wouldn't be sufficient), then i saw nice Jim Galli's examples where i don't know what is the film size ... it's clear to me that i have to make my own tests but i'd like to know something about the image circle in advance.. so if anybody knew something .. i'd be glad.

all the best,

m.

[misok]

Thanks for a fast reply, Master.

I'm happy with that information and i will post my results asap.

[Dan Dozer]

Just to throw in my 2 cents here - I have a 14" Dallmeyer Serrac serial #219001 with the AM also showing on the side. It covers fully 8" x 20" at F4.5. I don't know yet what the image looks like at the corners/edges because I've really only used it once before on a portrait with a dark background, but it does cover that size negative fully open.

[misok]

great, thanks.
so i got it, looks as i expected, paint 40% (looks more like a part of submarine, not a plane), aperture blades 100%, optics 80% (which is ok for me) ..but since i read only good things about it, i decided to restore it completely (incl. paint). rear group came off and bits of mushrooms cleaned nicely but with the front one i'm hopeless .. i'd need a pneumatic hand to unscrew it. there's some haze around the edges and dust but i think i'll ignore it. it has quite authoritative look though.

[seananton]

According to Dallmeyer's literature the Serrac is always f4.5, Dallmeyer do not list any large format lens at f5.6.

[goamules]

WWII Aerial photography lenses were very much in demand at the time, and are quite often very poorly documented. They were military secrets as well, which made the documentation even better hidden...

And then there are the WWI, or "Great War" aerial recon lenses, such as my Dallmeyer 5D:

Before:
http://www.collodion.com/forum/uploads/688/DALL_5D2.JPG

After:
http://www.collodion.com/forum/uploads/688/DAL5_AF.JPG

[Dan Fromm]

According to Dallmeyer's literature the Serrac is always f4.5, Dallmeyer do not list any large format lens at f5.6.Where, pray, are you looking? I ask because I've held an ex-Air Ministry 14"/5.6 lens with a Dallmeyer manufacturer's code in my hands.

[Paul Ewins]

I can second that: I've got two 14"/5.6 AM lenses, both are the 14A/3140 contract. One has serial no. 414789 and the other UU280897 which would make it a Dallmeyer manufactured lens.

[Jim Fitzgerald]

Well, I'll add my .02 worth to this thread. I have a 14" F 5.6 UU 285965 14A/3140 lens with a Burke and James sticker on it. Mine only is marked from F5.6 to F16 but it looks like it goes to F32? After seeing Jim's shots it looks like I better get this bad boy on a board and get to work.

Jim

[Dan Fromm]

Oh and by the way, y'all might want to count reflections to see whether your 14"/5.6 Air Ministry lenses are tessar types (4 strong reflections from the front cell, 2 strong and 1 weak from the rear, and the weak reflection can be hard to see) or dialyte type (Aviar, to be exact, 4 strong reflections from each cell). I handled, didn't buy, the tessar type Dallmeyer, bought and eventually resold an Aviar.

My memory is failing, so I could well be wrong, but I think Jim's 14"/5.6 came from me. In any case, he said in this thread that it is an Aviar.