leighmarrin
17-Aug-2010, 01:06
I recently picked up an old magic lantern petzval lens at a local antique store, pictured below in a bad digi-snap. Except for a few cryptic pencil marks on the element edges, it is otherwise unmarked. Any info on possible maker, decade of manufacture or country of origin is welcome.
The lens barrel is about 3.5" long, not including the front hood. The glass elements are about 1.6" across. Focused at infinity, it requires about 12" of extension to my guestimated nodal point, so I'm going to try using about f7.5 as a starting point. It fully covers 5x7 with movements, but not much swirl.. Ground glass image looks fairly sharp.
Almost all the metal is brass; barrel is nickel-plated and the brass flange has black enamel paint on one side.
I took apart the optics and compared them to a petzval diagram: they appear to be in the right order. The front cell is glued together and the rear is air-spaced.
The front cell edge has the pencil marks "RG 465" and a rear element is also marked "RG 365".
Wonder if "RG" might have been the maker; are there any 19th century optical makers with those initials? (Not Gundlach... his first name was Ernst; the "R" is definately not an "E".)
With some Norsigian-type wishful thinking, I'd like to believe that "465" and "365" are date codes for 3/65 and 4/65: perhaps each flint/crown cell assembly was completed in March and April 1865?! Probably not...
All info or comments welcome. Thanks for reading--Leigh in Santa Barbara
http://www.freeimagehosting.net/]http://www.freeimagehosting.net/uploads/91b5825663.jpg[/url]
The lens barrel is about 3.5" long, not including the front hood. The glass elements are about 1.6" across. Focused at infinity, it requires about 12" of extension to my guestimated nodal point, so I'm going to try using about f7.5 as a starting point. It fully covers 5x7 with movements, but not much swirl.. Ground glass image looks fairly sharp.
Almost all the metal is brass; barrel is nickel-plated and the brass flange has black enamel paint on one side.
I took apart the optics and compared them to a petzval diagram: they appear to be in the right order. The front cell is glued together and the rear is air-spaced.
The front cell edge has the pencil marks "RG 465" and a rear element is also marked "RG 365".
Wonder if "RG" might have been the maker; are there any 19th century optical makers with those initials? (Not Gundlach... his first name was Ernst; the "R" is definately not an "E".)
With some Norsigian-type wishful thinking, I'd like to believe that "465" and "365" are date codes for 3/65 and 4/65: perhaps each flint/crown cell assembly was completed in March and April 1865?! Probably not...
All info or comments welcome. Thanks for reading--Leigh in Santa Barbara
http://www.freeimagehosting.net/]http://www.freeimagehosting.net/uploads/91b5825663.jpg[/url]