Reversed-Element Tessar as a Soft Focus Lens (?)

[leighmarrin]

Several years ago I picked up a Graflex non-auto Series D 3x4 reflex that has an uncoated B&L 6 3/8" f4.5 barrel lens on it. The front cell was a little hazy, so I took it apart and cleaned it. Several years later I finally got around to using it, and was surprised how fuzzy and flarey the results were.

I finally figured out that I'd reversed the rear element of the front cell. With it correctly positioned, it's nicely sharp.

So here's a quickly done example of the effects of the correctly positioned versus reversed element on a 4x5 press camera, at f11, focused at about two feet:
http://www.freeimagehosting.net/uploads/6f4a3c0f84.jpg (http://www.freeimagehosting.net/)

[Larry H-L]

I reversed the front element of a 50mm Russian-clone Tessar and now use it as a soft-focus lens on a dSLR. Results are more pronounced than what you show, but perhaps that is because the 50mm is a faster lens?

[Jim Galli]

Tried this yesterday with a worthless Velostigmat 6 3/8" Enlarging tessar. Easily accomplished but difficult in the extreme to judge a focus and seems a bit too smeared to be useful to me. I ended up re-assembling the lens with the right orientation and leaving an extra 1/8th inch gap between the 2 front cells ala Velostigmat fuzz-u-lator. That seems to me to be a richer trade off.

BTW, I could not have produced the images above with the Velo, so maybe there's something to Brand differences, ie. B&L instead of Wolly Velo. I have a nice 5X7 B&L at home that I'll tamper with for another try.

[Eric Rose]

I think there is a difference between the soft focus look and just plain out of focus.

[leighmarrin]

More element-flipping with the same B&L 6 3/8" series Ic barrel lens, this time at f8 focused at about five feet.

I probably should have used an easily-recognizable test object, but I sorta like the mysterious fuzz... FWIW, this flarey-thing is an unusual electric-floral-sculpture hanging inside a storefront display window. The ends of the flower are small lights alternating with small shiny spheres.

Photos were taken at dusk, with only a little natural sunlight. The right-hand photo has the reversed element, and like the lantern shots, also has a small relatively sharp center.

http://www.freeimagehosting.net/uploads/9bca2e31b9.jpg (http://www.freeimagehosting.net/)

[leighmarrin]

And here's the reversed element with the lens wide open at f4.5 --Contrast was lower, so after scanning I increased it, and also decreased brightness a bit.

http://www.freeimagehosting.net/uploads/9effbd9367.jpg (http://www.freeimagehosting.net/)

Highlights away from the center appear to now have two or three "prongs". (Umm.. perhaps I could have got a similar effect with one of the many special-effects filters from the old Spiratone catalog or a vaselined UV filter, but this is "funner".)

[Paul Fitzgerald]

Thanks for posting this, I just received a B&L Aero-Tessar 600 f/6 and will try this out after I get it mounted.

[leighmarrin]

Paul, I'd be interested in your results, including the non-modifed ones. What sort of camera and lensboard is required for a 600mm Aero-Tessar?

[Paul Fitzgerald]

Hi there, the Aero-Tessar is one large lens, it needs at least an 8x8 board and at 24" it needs an Ansco 5A double extension studio camera OR some Air Force monster. It's 5 1/2" across the barrel and each cell weighs 5+ lbs, it's in a phenolic resin fiberglass barrel (really tight threads) and there is no provision for a mounting flange or iris assembly. Mounting it and installing an aperture was interesting. :eek:

The image is tessar sharp with less contrast being uncoated, nice choice if you can use it. Modified it's only slightly less drastic than the f/4.5 and adjustable by f/stop.

This conversion can be done to a B&L 8x10 Tessar 1C but not to the 11X14 or 14X17, the cells are crimped.

I was wondering how Hurrell did the photo below, this might not be the exact answer but it's really close.