Convertible Lensgreenspun.com : LUSENET : Large format photography : One Thread
I have a chance to buy a good working with clean glass old 8x10 Wollensak (Conley) triple convertible lens 12"-20"-28" in Conley shutter. Does anybody know everything about this lens? Is it a good lens for doing contracts with? Would it be easy to work with? Or should I forget about it and buy single focal length lens (all used)? Any information would be helpful. Thanks in advance.
-- John Miller (email@example.com), January 29, 2002
This is a classic lens. The design is based on the original Zeiss Protar deisgn, if memory serves right and later versions have the benefits of single coatings (not that it matters terribly in a Protar design - just 4 air-glass surfaces). It will make some really nice contact prints. I like convertibles, the weight savings are great and I like the rendering also. Cheers, DJ.
-- N Dhananjay (firstname.lastname@example.org), January 29, 2002.
Hi John, is the lens a Series IA Raptar? or how old is this lens? David
-- david clark (email@example.com), January 29, 2002.
I don't know how old or if it's a raptar. It's just nice and clean. I hope this helps.
-- John Miller (firstname.lastname@example.org), January 29, 2002.
If it says Conley, It's probably before 1920 - way pre-Raptar. However, the images some of these old lenses can make is nothing short of magical. Just use a good lens shade and probably stick with monochrome film. If it's under a $100 and the shutter still works, what the heck.
-- Chauncey Walden (email@example.com), January 29, 2002.
The Raptar is a Tessar-like lens, so the basic design pre-dates 1920 by more than a decade.
-- Pete Andrews (firstname.lastname@example.org), January 30, 2002.
Pete, Wollensak's "Raptar", like Kodak's "Ektar", is just a term referring to a quality level of that company's production - especially referring to coating and usability with color film. The actual lens design may be almost anything, Tessar, Heliar, Protar, Gauss, etc. John's lens is probably from an 8x10 Conley which was produced from 1908 to 1917. The shutter may even be a simple two-bladed one. John?
-- Chauncey Walden (email@example.com), January 30, 2002.
The lens is a 3 focus rapid rectilinear Ser#2996 in conley shutter shutter,t,b,1-1/100. Hope this helps and thanks for the answers so far.
-- John Miller (firstname.lastname@example.org), January 30, 2002.
Ah, that helps. This is a convertible rapid rectilinear design (similar to the Gundlach rapid rectigraphic, althought the Gundlach lens appears to have been just a way to get around patent issues). The rapid rectilinear is a pretty important design historically and these lenses were fitted to a heck of a lot of cameras. The front and rear components are similar but not identical. As has happened on more than one ocassion, 2 people came up with the same design at more or less the same time (Dallmeyer came up with the rectilinear and Steinheil with the Aplanat - both of the are essentially similar designs). The lens consists of 2 groups of 2 elements.
Kingslake says the lens was probably fairly expensive to manufacture due to the strongly curved internal cemented surface - to that extent, a lot probably depends on the quality control at each firm that manufactured these designs. However, the lens aberrations were apparently well maintained through a wide variety of distances.
I've used the Gundlach rapid rectigraphic (which basically consists of 2 groups of 3 elements each but this appears to have been just a way to get around the patents - the design is identical, one of the elements is just split). With both elements, you get the shortest length. With the rear element alone, you get the middle length and with the front element mounted behind the stop, you get the longest length. The lens is not a true anastigmat. As such, any later anastigmat design (the Dagor, Protar etc) is going to perform substantially better. When used converted, it really is pretty grim, you will need to stop down a fair bit to get some degree of sharpness (and even then, it isn't really sharp). People differ in what they consider sharp and want in a lens. IMHO, the lens makes acceptable images (especially when used as a full lens) as long as you're contact printing and sharpness isn't the criterion being used to judge the pictures. Cheers, DJ.
-- N Dhananjay (email@example.com), January 30, 2002.
John, I have the same Conley lens in its 5x7 form. I've only used it at its shortest focal length because testing there showed that although it was quite contrasty and sharp in the center and mid-image, the corners were suffering somewhat. It's a great "old-time effect" (although I have even older lenses that will make a perfect image). The biggest drawback to me is the hands-on shutter release. If I were going to use it regularly, I would rig up a bracket on the lens board that would allow the use of a cable release. Have fun.
-- Chauncey Walden (firstname.lastname@example.org), January 31, 2002.