Bausch & Lomb Identification

[rmagnell]

Hello!

So I bought an old lens from eBay hoping I could make it work in my Graphic View 4x5. All I know is it has "Bausch & Lomb Rochester New York 220523 written on it. Can anyone shed a bit of light on the story of this lens? There is no aperture control or shutter.

Thanks,

Rick

149850
149851

[rmagnell]

I measured the diameter of the lens which I believe is 35mm if I'm reading this old dial calliper correctly. Also I have read the focal length is measures from the rear element to the film plane? I'm assuming I'm going to have to shoot in somewhat low light so I can manually expose the film with a home made lens cap.

[Steven Tribe]

This is a smaller projection Petzval. Focal length is measured from the optical centre of the lens to the film plane when it is focussed on an object at infinity. The focal center on this kind of Petzval will be about 3/8ths of the way up the barrel from the rear end. A distant house or tree will approach infinity!

It may not quite cover 4X5".