Goerz Dogmar Lens Question - Soft Focus?

[Anthony Oresteen]

There's a 4x5 lens listed on eBay as a soft-focus Dogmar. It's a C.P. Goerz Berlin Dogmar 21cm f/4.5 'Soft Focus Portrait Lens' .

Are Dogmar lenses soft-focus?



I'm thinking about using it with my Hasselblad.

Thanks!

[seven]

short answer is - no.

[John Kasaian]

From the vade mecum:

"Dogmar A new dialyt series was announced in Photography 26/05/1914, working at f4.5 in the shorter foci. Since it was very late prewar, most examples will be postwar. Adverts. stressed it was a very highly corrected lens, but the major sales feature was that it was separable, the front cell giving 2x focus, and the rear one 1.5x focus. It was said to be free from ghosting, and the f4.5 was initially made in up to wholeplate size, the longer sizes being in f5.5. It covers 55? or 54? at full aperture, and 60? at smaller apertures. It was suggested to use 21cm for 13x18cm plate. The f5.5 covered a slightly larger angle (54-60?) and a slower version at f6.3 covered a bit more again (60-65?). However it was not primarily sold for its angle of cover, and the slower version was short lived, being replaced by the Tenastigmats, etc. The designer was W. Zschokke, and it was covered under Patent 258,494 and sold from 1914. It is sharper than Celor, and shows better edge detail than the Q15 type designs. [Zschokke then left Goerz after the association as Zeiss Ikon, and designed rather similar lenses for Kern, possible perhaps due to the take over by Zeiss Ikon and the absence of this lens type in the Zeiss lists.] Dogmar f4.5 60, 75mm for 2.375x2in, 90mm for 2.75x2.375in, 100mm for 2.5x3.5in, 125mm for 4.25x3.25in, 125mm for 4.25x3.25in, 135mm for 4.25x3.25in, 150mm for 4.75x3.5in, 165mm for 5x4in, 180mm for 6x4in, 195mm for 6.5x4.75in, 210mm for 7x5in, 240, 270, 300mm. Use 165mm for 5x4., 14in for 10x8. Separable, 3 focus. It covers 55? and there is no suggestion of improved cover when closed down. The other foci of the single cells were not detailed in adverts (eg B.J.A. 1925, p739)"

[Jim Galli]

Dogmar is basically a dialyt, like an Artar. So, intrinsically a very sharp lens, but, they suffer from non image forming light that can give them an "old school" sort of feel. They have 4 glass in 4 groups. So 8 surfaces for air to glass. You lose roughly 4% of your image forming light per surface. So we're getting up around 30%. On interiors, sometimes that actually works for you, lighting up the shadows. Contrast is low.

[IanG]

While it's definitely not a soft focus portrait lens it may be soft in terms of contrast and sharpness if it's not very clean. With 8 air-glass surfaces it's more prone to flare than a similar age Dagor etc but they are excellent sharp lenses when clean

Ian

[Anthony Oresteen]

Thanks guys! That's a lot to absorb & think about. If the price doesn't astronomically high, I may jump in.

I've been adapting a number of lenses to be used on my bellows and Hasselblad 2000FC/M (focal plane shutter) and this one struck my eye.

[IanG]

Don't pay too much for it unless you can see it first hand. The photo you posted would put me off this particular lens, which is in a sunken mount, you also need the flange (if one's not included). I have a few Dialytes and they all look (and are) an awful lot cleaner than this lens in photograps.

When I first joined this Forum Dagors were the "Cult" lens, you see far fewer for sale now and Dogmars seem to have been rising in value as a consequence. I know it's not as fast but the 203mm Kodak Ektar (also a Dialyte) is a far better lens and being coated is almost flare free and usually in a shutter. The coatings improved and later versions in Prontor or Compur #0 (Kodak Ltd, British made) and Compur #1 (Eastman Kodak) are the best.

Jim Galli's point about the 4% image loss per air/glass surface is important (not sure about the figure I thought it was more like 1-2% but whatever it is it's highly relevant when compounded up) it's the internal surfaces that matter the most, a Dogmar has 6, a Dagor has 2, a Tessar 4. add in scratches dirt etc and that has a profound effect on the final results.

Ian

[Bill_1856]

Dogmars were often sold with 3-color-seperation cameras because of true apochromatic effect.

[Jim Galli]

Dogmars were often sold with 3-color-seperation cameras because of true apochromatic effect.

Didn't know that, but it makes sense. Like a real fast APO Artar.

[Dan Fromm]

Dogmars were often sold with 3-color-seperation cameras because of true apochromatic effect.

Interesting. I've seen one-shot color cameras with Dogmars but I think you're reading too much into that.

The 1951 Goerz catalog (see http://www.cameraeccentric.com/html/info/goerz_3.html) says that the Dogmar's"high color correction makes it a fine lens for color separation, Kodachrome and other color films" but doesn't assert that it is an apochromat. Goerz certainly didn't offer it as an alternative to the Artar for process work.

The catalog also makes clear that the Dogmar, unlike the Artar, is asymmetrical. That is, the two cells have different focal lengths. Its says that "at their maximum aperture the single elements produce artistic, soft effects." This may be where the OP's idea that Dogmars are soft focus lenses came from.