Info on Voigtlander brass lens

[gbogatko]

I recently acquired a Voigtlander brass lens. All 5 lbs of it. Serial # in the 19000+ range, putting it somewhere around 1868? Comparing focal length against a 14.5 in. Wolly Verito, it appears to be in roughly the same 14.5 inch range. I'm gonna try to make my own waterhouse stops (wish me luck).

Anyway, the rear-most element is faintly yellowed and seems to have minute ripples all over the glass. a) what are the ripples. Is it possible it was used as a projection lens (it has the crank on it) and the element partially melted? b) I haven't mounted it on a board yet, so what do you supposed these ripples are going to do to the image?

I plan to put it on a 6x6 cambo board (for a 4x5). It's the only camera I have. I could borrow a Century, but I don't have the facilities to develop 8x10 sheets.

Just for giggles, does anyone have a spare flange for something this size? I used rubber tubing and a hose clamp for the Verito, and could probably do the same thing for this one.

Cheers,

George Bogatko

[Ole Tjugen]

That yellowing could be balsam deterioration? I have a little of the same on one of my old lenses, a Steinheil Aplanat. The rippling could be the balsam as well - but that's between two cemented elements. The elements are glass and shouldn't melt before the barrel does! If the "ripples" are on the outside, I would try to clean it :)

You're not really giving me enough clues here. It could be a Petzval, or an aplanat, or something else.

[gbogatko]

It's a petzval. Cemented in front (clear), then two air separated elements in the rear. The innermost one is clear, the outermost one has the (very) faint yellowing and the subtle rippling. The rippling is only visible when you look thru that single element, and is much much less when looking thru the two rear elements in combination. But (always but) even with all in place it never quite goes away. Since the lens dates from 1862 I wonder if it's the effect of age or that's just the way things worked out in 1862.

Cheers,

George

[Ole Tjugen]

If it's a Petzval, then the yellow rippling stuff is a coating of gunk on the lens. Nothing could make glass go "ripply" without destroying it completely.

Peter Wilhelm Friedrich Voigtländer was a very fine lens maker, and I find it hard to believe he would have let "sub-standard" lenses out of his workshop.

[gbogatko]

Ah. This then begs the question of how to remove the gunk. If this is tricky, error prone and likely to really damage the lens, then it's ship-it-to-an-expert time (something tells me that steel wool is a no-no :p ). If it's simply a matter of soaking it in dish-washing solution or alcohol for a while then I may have a go at it. More dreadful than anything is the possibility that granny sprayed it with lacquer to keep the brass shiny (acetone anyone?). Any suggestions?

Cheers

[C. D. Keth]

www.skgrimes.com ;)

[gbogatko]

>> www.skgrimes.com

Awww. Thats no fun!!

[C. D. Keth]

>> www.skgrimes.com

Awww. Thats no fun!!

Maybe, but they can confidently advise you on what to do about the gunk and not harm the lens.

[gbogatko]

Got home, and on the advice of those before me, took out the rear element, held my breath, and soaked it in acetone. The crud just about floated off as a sheet. Real smeary and icky. I guess granny DID hose it down with some brass spray. Then I used window cleaner and a soft cotton cloth, followed by a micro-fiber lens wipe.

Result: It looks brand new. Not a flaw present. It looks like granny's mistake protected it from the dust all those years.

Thanks to Adam at SKG and Jim Galli.

GB

[C. D. Keth]

Sweet! You should have a very, very nice lens now :-D

[Ash]

Got any pics? I'd like to see the lens after the acetone treatment.

[Aaron van de Sande]

I would be careful dipping lenses joined by balsam in acetone. I would think you would start to see edge seperation pretty quick!

[Pete Watkins]

I used to work for a company that repaired and calibrated surveying instruments and we used ether to clean the lenses. This was in pre-digital days. Don't sniff it and don't smoke while you're using the stuff.
Best wishes,
Pete.

[gbogatko]

I managed to mount it on a cambo board and made some waterhouse stops. Here's the first photo (ordinary stuff). This is at what I think is around f16.

gb

[gbogatko]

I would be careful dipping lenses joined by balsam in acetone. I would think you would start to see edge seperation pretty quick!

Ah. In this case, it's the front element that's cemented. The rear set is air-separated, so the only thing dipped was a solid chunk of glass (no glue.)

gb

[gbogatko]

A few more, at various openings. One at f32 (2nd from left), showing how it does closed down. The third from the left shows the petzval swirl effect.

gb