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Hello,
I'm looking to find out a little more information on a lens I just found at an antique store.
It's a Bausch and Lomb. I measured (roughly) the focal length at 24" and the aperture at f6 (edit, see next comment). I didn't take it apart, but it appears to have one element in the front and two at the back.
I'm wondering if this is a petzval or triplet design and if anyone would have any extra info on it.
Thanks!
Ross
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Measured it again at home. It's listed faintly on the side of the lens as a 15" FL, but I measured it out at 16". The visual opening at the narrowest part of the lens is about 3.75". Think that makes this lens about a 400mm f4.2.
some information here http://cameraeccentric.com/info.html
It's a projector or magic lantern lens. They made many in all focal lengths, most speeds down to about F5. Some are much slower. If it's airspaced in the rear, it;s a Petzval. They also made triplets.
Thanks for the info guys ���� I may try taking it apart to see if the rear is air spaced.
Took it apart. It's a petzval! The rear has two elements and the front appears to have two cemented.