2 lens questions: Heliar, Eurynar

[Antonio Corcuera]

Dear all,
I have just been given these two lenses, a coated 24cm f:4,5 Heliar and a 13.5cm f:4,5 Doppel Anastigmat Eurynar. Being totally unexperienced with vintage lenses, here are my questions:
1. Regarding the Eurynar, the serial number gives it a 1925-28 vintage, so it should be uncoated. However, the reflections of the front element go from green to purple, and on the rear element from purple to straw yellow. Could it have been multicoated later? On another note, what is approximate coverage of the lens - will it cover 4x5? Maybe Ole can help me on this.
2. The Heliar is beautiful, but… it has what seems to be cement/balsam failure. Please see the pictures attached. What is it and is it worth cleaning/repairing?

Thanks!

[Ole Tjugen]

1: The Eurynar should cover 4x5" just fine; mine covers 9x12cm with movements and 5x7" not at all - I haven't used it on 4x5" yet. One of mine has also been coated. With 8 surfaces there is a tremendous difference in contrast between coated and uncoated versions of these, and regardless they are incredibly sharp. Since the eurynars can be easily dismantled for coating, I guess it was popular to do this as soon as it became possible.

2: The balsam fault won't harm the picture quality. Use the Heliar - it's a wonderful lens. A 240mm such as yours is among the best portrait lenses for 4x5" ever made - it also covers 5x7", and 8x10" at portrait distances (in my experience - published data will say different. But most of the published data are for the Heliar lens type, and nearly all Heliar lenses sold are really Dynar lens type).

[Glenn Thoreson]

The colors you see on your Eurynar could be "bloom". It comes from the minerals in the glass, and lots of age. It's a good thing, often refered to as self coating. It's said that lens bloom was instrumental in the idea of coating lenses. Maybe, maybe not. I have the same lens but mine is crystal clear.

[Antonio Corcuera]

Thanks Ole and Glenn. Having used only modern MC lenses, I really look forward to trying these two oldies and especially trying some heliar portraits!
Cheers

[Ole Tjugen]

The colors you see on your Eurynar could be "bloom". ...

I have a "blooming" lens - a 150mm f:3.5 Xenar Typ D - but I also have a coated 1926 Eurynar, and another Eurynar a year newer without the slightest hint of "discoloration". So my conclusion is that since the Eurynars can be separated into single elements simply by unscrewing lens after lens, they were prime candidates for post-production coating. Since they consist of four separate elements they would also benefit greatly from this - and the sharpness is absolute top rank, even compared to the latest lenses.

One thing you will discover with the Eurynar is that it's sharp - almost painfully so.

[Glenn Thoreson]

Ole, you know, I've never gotten around to using the thing. In fact, I don't remember it being a Doppel Anastigmat. I'll have to look. Too many lenses. I'm sure your one example has been coated at some point. Antonio's example, I believe is bloom. Green/purple is the usual color on this. I have a couple of Kodak Anastigmats with beautiful bloom. Need to try those, too. One note on the Heliar separation - I have a Zeiss Pro Tessar lens with horrible separation. It doesn't seem to affect functionality at all. I tend to think the only thing that would be a problem is if the cement had deteriorated and turned all funky brown and nasty.

[Dan Fromm]

Guys, separations can be a real problem. I have a 25/1.4 Cine Ektar II. The 25-15 w/a converter that came with it is separated, shows very strong Newton's rings. These are visible through the camera's finder and showed up on the test footage I shot with it.

[Brian Bullen]

[QUOTE=Ole Tjugen;263765]2: The balsam fault won't harm the picture quality.[QUOTE]
I've always been curious about this, how can something so obvious not affect the quality? It seems at the least this kind of separation would cause flare, if not some softness of image. If somebody could explain why it doesn't affect the image quality I'd be a little more inclined to believe the statement. Usually I hear this when there are scratches, separation, or some other anomaly.

[Antonio Corcuera]

I'm pretty sure the lens separation will not affect when stopped down (using only the lens' centre) but since the beauty of the "Heliar effect" is rendered wide open we'll see if it degrades the image for apertures under f:8. I still have to find a board to mount the lens, so I'll probably test it in September.

[Glenn Thoreson]

The separation on my 35mm Pro Tessar is a good 3/8" into the lens, all around. Probably more. It looks like a big oil slick. It's very visible, shocking actually, when looking at the front, but looking through the rear of the lens, it can't be seen. It has no discernable effect on image quality, for some reason. I'm sure each case will be different, though.