Bausch & Lomb Projection Lenses

[rob_gervais]

Okay, so I'm just getting started with LF and have a couple B&L E.F. Projection Lenses. They appear to be of different design. The 12 inch lens is a triplet. When you unscrew the front element, there is a brass barrel that sits inside the nickel barrel. The center and rear element are in the brass barrel.

The 22 inch lens, however, is only two elements and they both screw directly to the nickel barrel.

My question is -- is this correct, or am I missing a center element on the 22 inch lens?

Sorry if this has been covered previously, my search didn't show up anything for the 22 inch variant of this lens. Thanks!

Rob

[Steven Tribe]

The 22" has probably two single lenses in the rear cell - or at the front as these are often assembled incorrectly 'cos of similar threads). This is called a Petzval design. The triplet is a later projection type which looks (externally) almost the same.

[Mark Sawyer]

Steven is right that it could be a Petzval, but by your description it's missing one of the rear elements. It could also be a triplet missing the middle element. If it is missing an element, it would throw the focal length off, or render the lens unable to throw an image. I'd give that a quick check first.

If you take the front element completely out of its mount, you can inspect the side to tell whether it's a cemented doublet (Petzval) or a single element (probably part of a triplet).

[Jim Galli]

Got any pictures Rob?

[rob_gervais]

The first image is the 12 inch lens with all elements removed, front element to the left.

The second and third image are the 22 inch lens. The first shows the two lens cells removed, front to the left. The third shows all the lens elements.

I wasn't aware the cells would disassemble when I first received the lens. Looks like a Petzval design, all right, cemented pair up front, two in the rear. The only thing was the rear cell was assembled incorrectly. The layout of image 3 shows how the rear cell came apart - spacer, lens, lens. As a result, there is now a rub mark in the center of one of the lenses - but I'm only going to shoot B&W, so I'm not sure it'll have too great an effect.

I've reassembled the rear cell with the spacer between the lenses - but I don't knowthat the last lens will ever come out again, the spacer was a very tight fit.

Thanks for the input, folks. I'll be posting more as my camera comes together. Spent my cash on glass - time to put tools to wood, we'll see how that goes.

BTW - Jim G., I saw your portraits at http://tonopahpictures.0catch.com/Bokeh/Bausch&LombProjectionPetzval.html. I think they're great and it's the type of stuff I'd like to shoot. My plan is to shoot Liquid Light on glass plate, though, see http://www.alternativephotography.com/process_dryplate.html. I'm not all that far from you - passed through your neck of the, um, woods this past summer on the way to Great Basin.

Warning: my virus scanner pops a warning if you go to http://www.alternativephotography.com.

[Jim Galli]

Thanks Rob. That 22" Petzval is a treasure and you're very lucky to have it. Here are 4 images done with my 24" which is for all intents and purposes the same. 7X11, 8X10, and 6.5X8.5 Have fun.


http://tonopahpictures.0catch.com/711Tongs24Petzval_1m.jpg
tongs

http://tonopahpictures.0catch.com/1908/Fowler_Fallini.jpg
1908 great race re-enactment

http://tonopahpictures.0catch.com/Harrahs011409/1907ThomasInShopVertS.jpg
1907 Thomas Flyer i

http://tonopahpictures.0catch.com/Harrahs011409/1907ThomasInShopHrizS.jpg
1907 Thomas Flyer ii

It's a fantastic lens. It won't give you all the swirly wirly's that are currently trendy, but it's got it's own unique classy personality.