35mm Slide Projector vs Petzval Projection Lenses

[Peter Lewin]

Seeing so many neat soft-focus shots attributed to "Petzval Projection Lenses," are modern(ish) 35 mm slide projector lenses typically Petzval formulations? I have an old (let's say 1960-70s) slide projector in the garage, would be willing to try the lens as a taking lens, but don't want to disassemble and potentially ruin the projector if the lens won't have soft focus effects or will have nowhere near the coverage for 4x5 (while I haven't used the projector in years, I do still have lots of slides sitting in drawers).

[cosmicexplosion]

On eBay you can buy very cheap slide projectors.
I am doing a project with em at present

Get a single one and rip it to shreds!

[Jody_S]

It certainly won't cover 4x5, nowhere near in fact. And if it's from the 60s-70s, there is little chance that it's a Petzval design. That doesn't mean it won't make interesting photos on a smaller format.

[Tim Meisburger]

Most projectors have removable lenses. You can just pull it out, chuck it in a cardboard and duct tape lensboard, and see what you get. Or, just hold it up near a wall across from a bright window and you will get a sense of focal length and image circle.

[coisasdavida]

I did just what Tims suggested with the lens of a Kodak slide projector that my father bought in the 70s. It was a zoom lens. Small IC, not interesting... But I didn't try on film.

[jcoldslabs]

I bought an old off-brand slide projector at the thrift store a few years ago mainly for the lens. I was able to to take some shots with it on Polaroid pack film and the lens covered that format, which is 9x12cm or so. At non-infinity distances it would likely cover 4x5, too. When I took the lens apart to clean it I learned that it is a triplet. Not overly soft or Petzval-like, but fun to play around with. Here is one shot taken with it:



Jonathan

[Peter Lewin]

Thanks everyone! I now have my Bell & Howell Trionar 4" f3.5 projector lens mounted on my custom KB Canham lens board, ready to play! Of course, the custom lens board is really a "Meisberger special," since per Tim's instructions, the lens simply pulled out of the projector, and some card board from the recycling bin in the garage did the trick... Now using my "special" supply of incredibly out-dated but only moderately fogged 1983 Tri-X, and the old bottle of HC-110 in my basement, I'm ready to play. The image circle certainly doesn't cover 4x5, but since all I'm wasting is my time, it gives me a Sunday project, and Emmit Gowin has some classic photos of his wife Edith showing the circular image of a too-small image circle in many anthologies. If I get any images of interest, they will be posted this week! (Hey, if they are really interesting, I may even break out the HP5+ and PMK.)

[Emmanuel BIGLER]

Just to confirm what has been posted above regarding the effective image circle of a 35 mm projection lens used in inifinity-focus position: I have been able to project 6x6 slides with a low-cost triplet projection lens of 100 mm focal length, designed for 35 mm slides.
Hence the image circle of such a 100 mm triplet lens is at least 80 mm in diameter (= diagonal of a 6x6 = 56mm x 56 mm slide), much bigger than the nominal 43 mm diameter covering a of a 24x36 mm frame.
The actual image size of the "small" polaroid 100-series in packs of 10 (e.g. 665) is 73x95 mm (~ 3" x 3"-3/4) the diagonal is about 120 mm.

[jcoldslabs]

The actual image size of the "small" polaroid 100-series in packs of 10 (e.g. 665) is 73x95 mm (~ 3" x 3"-3/4) the diagonal is about 120 mm.

I stand corrected. The Polaroid film box states that the pack film is 3.25" x 4.25", but the actual image area (minus the white border) is indeed 73mm x 95mm.

Jonathan

[Tim Meisburger]

Great!. I'm sure it will be interesting. I like messing around with things like that. Over the holidays my family and I were visiting my mother in Tucson for a while, so I went out to the garage and made a linhof board out of some thin plywood, mounted a piece of cardboard shipping tube on it with white glue, installed a cheap (99 cent) magnifying glass lens in it using an old tube of silicone caulk, cut a slot in the top and made some waterhouse stops out of cardboard, then spray painted the whole thing black. Used it to shoot two portraits of my sisters (wide open f 2.8) and developed the negs today. They look pretty good, and makes you wonder why we spend so much for lenses (must be the shutter...).

Looking forward to seeing your results!