What is the difference between Goerz Artar, Celor & Dogmar?

[Brian Albin]

They all are four element symmetric designs with flints to the middle and a larger air gap between the pair of doublets than within them between the crown & flint.
Celor however, has a much shorter central gap than has Artar.

Are they equally sharp? Why were the second two brought to the market after the first one existed?

[E. von Hoegh]

They all are four element symmetric designs with flints to the middle and a larger air gap between the pair of doublets than within them between the crown & flint.
Celor however, has a much shorter central gap than has Artar.

Are they equally sharp? Why were the second two brought to the market after the first one existed?

The Artar is an apochromatically corrected process lens. The Celor is a relatively large aperture taking lens, the Dogmar is similar. There was also a Syntor and a Gotar to the same design.
In a nutshell, they each do something different. You can learn more by reading the Goerz catalogues at cameraeccentric.com.

[Ken Lee]

I corrected the font for readability.

[Hermes07]

They all are four element symmetric designs with flints to the middle and a larger air gap between the pair of doublets than within them between the crown & flint.
Celor however, has a much shorter central gap than has Artar.

Are they equally sharp? Why were the second two brought to the market after the first one existed?

The same reason that Zeiss made f/6.3 Tessars, f/4.5 Tessars, f/3.5 Tessars, f/2.7 Tessars, Apo-Tessars, Tele-Tessars, e.t.c. All superficially the same design but there's a lot of adjustment possible within the basic layout.

Also, think I'm right in saying that the Celor came first rather than the Artar.

[E. von Hoegh]

The same reason that Zeiss made f/6.3 Tessars, f/4.5 Tessars, f/3.5 Tessars, f/2.7 Tessars, Apo-Tessars, Tele-Tessars, e.t.c. All superficially the same design but there's a lot of adjustment possible within the basic layout.

Also, think I'm right in saying that the Celor came first rather than the Artar.

You are, 1899 as the Typ B. The Artar appeared in 1904. There was a short-lived dialyt lens called the Alethar (with each inner concave element made up of three glasses) an earlier (1903) attempt at an apo. process lens, which was dicontinued when the Artar was brought out

[Jim Galli]

Good answers. Also worth noting that even though it was a certainty that the dialyt design was one of the sharpest anastigmats ever devised, they suffered terribly from what we call flare. Each non coated reflective surface loses about 4% of the image forming light. That means in a Dogmar, over 30% of the light going in isn't forming an image, its just making fog. That's why the Artar was an instant legend as soon as anti-reflective coatings were perfected.

[Brian Albin]

Thank you for the replies.

[Dan Fromm]

The same reason that Zeiss made f/6.3 Tessars, f/4.5 Tessars, f/3.5 Tessars, f/2.7 Tessars, Apo-Tessars, Tele-Tessars, e.t.c. All superficially the same design but there's a lot of adjustment possible within the basic layout.

Also, think I'm right in saying that the Celor came first rather than the Artar.But Nick, Tele-Tessar is a trade name. A classic T-T's cross-section is not at all like a Tessar's

[Hermes07]

But Nick, Tele-Tessar is a trade name. A classic T-T's cross-section is not at all like a Tessar's

Dan, had a feeling some smartarse might point that out :)

Fair enough it doesn't look like a standard tessar in cross section but the classic f/6.3 version sold in the early 20th century was still essentially a tessar design - air spaced front doublet, then the aperture, then a cemented rear doublet. The more modern tele-tessars are a different story I agree.

[Dan Fromm]

Dan, had a feeling some smartarse might point that out :)

And you were right.

[J. Patric Dahlen]

Goerz Celor, Syntor and Kalostigmat were replaced by the new and better Dogmar. There was also the cheaper Tenastigmat, that replaced the 6.3 Dogmar. I have a 6.3/135 Dogmar in a Compur shutter, and it's excellent. It is sensitive to flare, though, but the low contrast can be corrected when you develop the film or when printing.

[Ken Lee]

Are Fujinon C lenses based on a modified Celor design ? If so, why ?

[Arne Croell]

Good answers. Also worth noting that even though it was a certainty that the dialyt design was one of the sharpest anastigmats ever devised, they suffered terribly from what we call flare. Each non coated reflective surface loses about 4% of the image forming light. That means in a Dogmar, over 30% of the light going in isn't forming an image, its just making fog. That's why the Artar was an instant legend as soon as anti-reflective coatings were perfected.
Why did that not happen to the f/4.5 Dialytes for pictorial use, I am wondering? Coating was available after 1945 for them too? I know that Steinheil produced a few coated Unofocals, but otherwise they are not common.

[Roger Hesketh]

T.T&H coated their f6 Series IIIb Aviars. I suppose an Aviar could be considered to be a dialyte. Are Unofocals Dialytes? Although they have the similar layout. I thought they had a different optical formula.

[Arne Croell]

Unofocals are dialytes. They got their name because all lens elements have the same focal length, just with opposite signs. Thanks for the reminder about the Aviars.

[Roger Hesketh]

I knew about the lenses all being the the same focal length.That was why I thought they might be different. Thank you for the clarification of the terminology.

[Dan Fromm]

Roger, TTH coated nearly every lens they made starting sometime in 1944. As part of last year's spring cleaning I gave Mr. Galli a coated 5"/4.5 Aviar (Ser. II, I think), s/n 292229.

Cheers,

Dan

[Roger Hesketh]

Dan you must have read my mind. I have just been having a bit of a rumage to find and check to see whether some of my series 2 Aviars are coated or not.I was curious. I was pretty sure they were but did not have the confidence of my conviction that they were until I'd checked. So I did not mention them. I knew all the series IIIB's were for sure. I have my lenses divided into lens sets to use with different cameras. So I have duplicates. Two series II 7" f4.5 Aviars S/N 321111 & 385095 are coated. An 8 inch Series 2 I have I am pretty sure is not coated but I can not lay my hands on at the moment to check. A series VIII f 5.6 12 1/2 Cooke telephoto of similar age s/n 310389 is also. Ross also coated their lenses early on as well I have some coated Xpres lenses of similar vintage too

Did you give Mr Galli the one you thought was a bit soft?

[Dan Fromm]

Did you give Mr Galli the one you thought was a bit soft?

Yes, that's the one. A 127/4.7 Tominon, ex-Polaroid CU-5, shot better on 2x3 than the 5" Aviar did. And its diaphragm was jammed. I told Jim that if he didn't accept it I'd toss it, also that if he took it and tossed it that was fine with me.

I'm still mad at Doug Jull, who sells on eBay as twybridge, for representing it as in good condition. Etched glass ...