Advice on Cleaning a lens from 1850 (approx)

[johnwsheldon]

I recently acquired a Voigtlander & Sohn petzval which had spent nearly the last century attached to a glass slide projector, and the last 50+ years of that in a garage or attic. I plan to return it to photographic duty if I can, but need some advice on how best to clean it up.

Link to image of lens body with inscription: https://jw-sheldon.com/wp-content/up...IMGP3675-w.jpg

One major modification was made to the barrel of the lens, probably when it was mounted to the projector: the focusing knob was removed and a makeshift twist-to-focus mechanism was made by soldering a post to the inner barrel which rides in a slot cut in the outer barrel. The interior of the inner barrel was also lined with something that looks like leatherette (maybe to minimize light leaks or internal reflections?), and that lining has fallen off and curled up inside the barrel of the lens.

Link to image looking into lens barrel, showing failed interior lining: https://jw-sheldon.com/wp-content/up...IMGP3714-w.jpg

The glass is quite dusty, as one would expect from years in storage, and I can't use it with a large lump of material in the middle of the lens. Does anyone have advice on relatively safe ways to remove the front or rear elements from lenses of this vintage and design? Anything I should avoid using when cleaning the glass?

I'd also like to clean up the brass a bit to get rid of some of the gunk and the stains while leaving the original coatings and patina where I can. Any advice for what products to use or to avoid?

I made a short video about the lens and the projector it was attached to, showing me removing the lens from the projector:

[Drew Bedo]

You might post this question in the Lens forum for better exposure.

I have looked into this for myself. Everyone says that the with the Petzval design, the glass elements may be unscrewed and dismantled to qallow gentle washing in soapy water by hand. . . .and reassembled.

I do not see well anymore and have lost some manual dexterity. I was afraid of fumbling the 150 year old glass and chipping an edge. So I sent it off to SK Grimes. They have taken care of that and it is in the mail back , expected this weekend.

Full disclosure: That cost me $193.00 including return shipping. Turnaround time at SK Grimes was 4-6 weeks.

I may get braver with handling another lens myself the next time.

[johnwsheldon]

Thanks! I'll post it over there also.

Good to know there's a pro I can use if I can't figure it out myself (and a reminder to have a padded workspace if I do try to disassemble it).

[Oren Grad]

You might post this question in the Lens forum for better exposure.

Sorry, we discourage posting the same question in multiple subforums. This subforum is appropriate, the question is nicely explained and the thread title is informative. You should get some good responses.

Good luck!

[Tin Can]

do not trash the projector

i look for then

[Drew Bedo]

Thanks! I'll post it over there also.

Good to know there's a pro I can use if I can't figure it out myself (and a reminder to have a padded workspace if I do try to disassemble it).

Oh no . . .don't consider ME to be a "pro". I am only a few weeks further along than you are. I sstill don't have my first brass lens back, . . .too intimidated by the thought of fiddling with it.

I will post a few images.

[johnwsheldon]

do not trash the projector

i look for then

I don't plan to throw it out! Parts of it are in pretty rough shape, and the bellows is a little worse off than I originally thought (mice did a number on the bottom of it where I couldn't see before getting the lens off), but there are some bits in very good shape that would be useful for someone looking for spare parts or a base unit to restore. This one at least has the huge central lens intact, and the chromed parts are still in decent shape with most of their original finish.

[johnwsheldon]

Oh no . . .don't consider ME to be a "pro". I am only a few weeks further along than you are. I sstill don't have my first brass lens back, . . .too intimidated by the thought of fiddling with it.

I will post a few images.

I meant SK Grimes, who you mentioned! I'd love to see some before and after pictures of your lens when you can.

[Drew Bedo]

I'll try to post some before and after sdhots.. . .I am e-challenged.

When I got it from e-Bay, the lens looked nice overall cosmetically. Condition as bought: The brass housing seems to be essentially un-tarnished. The lens barrel is Nickle plated and also looks pretty good. I do not think it has been polished, and I do not intend to do that going forward. The three main issues were (1) the glass elements looking dusty and (2) the mounting flange had hard crud on the surface that faces the lens board. Another flange issue was that it would not unscrew. The third issue was three missing screws from the radial drive housing over the pinion gear.

The folks at SK Grimes found screws to hold down the pinion gear housing. It now works smoothly but is stiff enough to hold the focus in place. The glass elements look to be as clear as the day they were ground (OK, that is hyperbole.). The big surprise for me was that the flange now unscrews smoothly and has no crud on the mounting surface. Total cost was $193 including return shipping via UPS.

Mayhbe I can post some imagers later today.

[Drew Bedo]

I don't really know how to get the pictures I want off the phone, then into the LF archive and then into this post.

Every time I do it I have to figure it out all over again. None of it makes sense and I give up. When I finally do get an image onto the p[oswt, I am not sure it is the one ai want, or they are in the wrong order and its always the wrong orientation. . . .which then cannot be changed. be changed.

Mixing Apple, with whatever version of Windows and the needs of LFP . . . .
TRech and post processing just isn't fun for me anymore.