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.Originally Posted by Brian Albin
In a nutshell, they each do something different. You can learn more by reading the Goerz catalogues at cameraeccentric.com.
Last edited by E. von Hoegh; 5-Mar-2013 at 13:47.
One man's Mede is another man's Persian.
I corrected the font for readability.
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
One man's Mede is another man's Persian.
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.
Thank you for the replies.
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.
And you were right.Dan, had a feeling some smartarse might point that out
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