150mm f4.5 C.P. Goerz Dogmar as a convertible

John Wiegerink · Jul 28, 2023

I have a very nice coated 150mm f4.5 Dogmar and was wondering about the placement of the lens groups in the shutter when using it converted. Using the front group alone gives 2X and the rear is said to give 1.5X times. The question is do I mount these in front of the shutter or rear of the shutter for best results. I know it makes a difference on my Schneider convertible Symmar.

Donald Qualls · Jul 28, 2023

It likely makes a difference whether this is a Dogmar (as in thread title) of a Dagor (the thing that pops into my mind reading "Dogar" above). Based on their designs, I'd expect a Dagor to give better results as a convertible than a Dogmar...

Dan Fromm · Jul 28, 2023

Donald Qualls said:
It likely makes a difference whether this is a Dogmar (as in thread title) of a Dagor (the thing that pops into my mind reading "Dogar" above). Based on their designs, I'd expect a Dagor to give better results as a convertible than a Dogmar...

Were there any f/4.5 Dagors?

John Wiegerink · Jul 28, 2023

Sorry guys! Yes, it's a Dogmar as the title says. I'll correct the post, since it must have been a brain fart popping up. I had a 6" f6.8 Dagor and it was a very good lens, but sold it a few years back. I then ran into a 165mm Rodenstock Eurynar (uncoated) that was great if you didn't let the sun anywhere close to the frame of the shot. That's why I was glad to get the 150mm coated Dogmar. I got it very cheap since it had a bad shutter. I rebuilt the shutter for another parts shutter and it now purrs like a kitty. I'm going to try it out for the first time tomorrow. I think I'll just leave the front and rear groups in the positions they are in now for conversion. I know the Dagor and Dogma don't cover the same, but I won't be using hardly any movements with the Dogmar so it should't matter.

abruzzi · Jul 28, 2023

According to a Goerz catalog the front is 1.92x and the rear is 1.52x. I assume it is intended to be used in its normal place when used singly, but it may just be worth trying it out in both positions.

Donald Qualls · Jul 28, 2023

The only lens I have that works as a convertible is a Componon (150 mm f/5.6); it does a fine job with just the rear group in its usual position, but I've been told the front group, either in front of the shutter or reversed behind it, gives inferior image quality. Componon is a 6-element and gives about 265 mm with the rear group; diopter math says it ought to be close to 345 mm for the front only, which might well be pushing the quality of the glass a little. Maybe next time I have my Graphic View II out of the case I'll have to shoot a couple sheets with the conversions and see if I've been cheating myself.

Your Dogmar is a 4-element Dialyte, according to my quick Google search earlier. Might be better, might be worse than the Componon (or might just be different, since the Componon is officially an enlarging lens).

John Wiegerink · Jul 28, 2023

abruzzi said:
According to a Goerz catalog the front is 1.92x and the rear is 1.52x. I assume it is intended to be used in its normal place when used singly, but it may just be worth trying it out in both positions.

Yes, it's probably worth four or so sheets of 4X5 just to find out.

JPD · Jul 29, 2023

The Dogmar is a very good dialyte, so it's not surprising that someone had the lens coated. Is it the German or American version?

When using one of the components only, I suspect it to be a little better than a simple achromat since the Dogmar is a double anastigmat. I haven't tried it with my Dogmars.

John Wiegerink · Jul 29, 2023

JPD said:
The Dogmar is a very good dialyte, so it's not surprising that someone had the lens coated. Is it the German or American version?

When using one of the components only, I suspect it to be a little better than a simple achromat since the Dogmar is a double anastigmat. I haven't tried it with my Dogmars.

German, C.P. Goerz Berlin and the main reason I bought it was because of it being coated. I checked dates of manufacture and it was made way before Zeiss or Kodak were coating lenses. My Rodenstock Eurynar has oxidation that looks similar to a very, very light coating, but I don't think it can have much to do with cutting flare. At least I don't see it cutting flare much.

JPD · Jul 29, 2023

John Wiegerink said:
German, C.P. Goerz Berlin and the main reason I bought it was because of it being coated. I checked dates of manufacture and it was made way before Zeiss or Kodak were coating lenses. My Rodenstock Eurynar has oxidation that looks similar to a very, very light coating, but I don't think it can have much to do with cutting flare. At least I don't see it cutting flare much.

The oxidation may not be on all the glass surfaces, and the inner elements are flint glass and may not have oxidation at all. I have a Steinheil Unofokal with extremely clear elements but no coating tint or rainbow effect of oxidation. It puzzles me. Other Unofokals I have have the typical uncoated look.

I hope you will like the Dogmar. My 135/6,3 Dogmar is very sharp, and it's not surprising since the Dogmar is the improvement of the already famous Celor and Syntor. I'm tempted to have mine coated. I have a 4,5 one as well but haven't tried it yet.

John Wiegerink · Jul 29, 2023

I have one 135mm Unifokal lens that's uncoated and it matches your description. I just received a 135mm f4,5 Dogmar fro a fellow in Buligaria and it's spotless. I haven't tried the 135mm f4.5 since I just received it yesterday, but it's going to go on an Ica Etui 9X12cm, which should make an excellent pair for traveling. I can fit the camera and ten holders in a small 35mm camera case. Not much in the way of movements, but should give me nice, sharp, big negatives.

JPD · Jul 31, 2023

You mean the KW Patent Etui?

I have my 135/6,3 Dogmar mounted on a Voigtländer Avus that originally had the 6,3 Voigtar. I don't need all the fancy movements, but I use a little rise sometimes.

Donald Qualls · Jul 31, 2023

JPD said:
KW Patent Etui

I had one of these for a while -- first large format camera I owned. If it had had a Tessar type lens I probably wouldn't have wanted better and traded it on...

John Wiegerink · Jul 31, 2023

Donald Qualls said:
I had one of these for a while -- first large format camera I owned. If it had had a Tessar type lens I probably wouldn't have wanted better and traded it on...

My 9X12cm carries an uncoated Tessar for now. They are the smallest, most compact camera with that size film format. Very nice little cameras.

John Wiegerink · Jul 31, 2023

JPD said:
You mean the KW Patent Etui?

I have my 135/6,3 Dogmar mounted on a Voigtländer Avus that originally had the 6,3 Voigtar. I don't need all the fancy movements, but I use a little rise sometimes.

Yes, that's want I meant.

150mm f4.5 C.P. Goerz Dogmar as a convertible

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