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A Wollensak Micro Raptar 115mm, f12.5...coated...barrel...I picked this wee little thing up years ago -- advertised as a good close-up lens for 8x10. I just found the lens again. A little bit of research came up blank and I will not have time to devote to it until the New Year. I'll be giving it a try later this winter...possibly up to 4x.
Anyone familiar with this lens?
Oh, my, another mystery lens. Does it have a fixed aperture?
f12.5 to f32 -- and as I mentioned a wee little thing. About 1.5 inches in diameter and an inch tall.Quote:
Originally Posted by Dan Fromm
Hmmm... I have a 108mm f/6.8 raptar that covers 5x7. It is the later version of a 4-1/4” Wide angle series III. Yours must be something similar if it is a Raptar. Mine is about that size without the shutter.
Raptar is a trade name, not a design type.Quote:
Originally Posted by scheinfluger_77
I have a 210 Graphic Raptar -- a whole different beasty.
Supposively the Micro Raptar is designed for close-up work, and being a 115mm, it should not tax my bellows too much. If I remember what I just read on the info pages, one doubles the focal length (bellows extension) for 1:1, and add another focal length for every single digit increase (230mm for 1:1, 345mm for 1:2, etc), I should get up to 4x with my bellows (575mm), if I got the theory right:
"You need an extension of two focal lengths to get a lifesize picture. After that, every increase of one focal length gives you one whole number of magnification. Example: A four inch lens at 12" extension (three focal lengths) magnifies by two."
Vaughn, you got the calculation right, but not the notation. 1:1, 2:1, 3:1, and so on for magnifications greater than 1:1.
If your lens didn't have a diaphragm I'd suspect it was a gauge projection lens.
Dang I had it your way first and thought I read different so I changed it. I thought it was subject size to image size. Thanks!
In the Info section it said, "You can take a picture of a small object with any lens, but for really good results you need a lens made for an appropriate conjugate ratio. This is a fancy way of talking about the ratio between the subject and the image."
Picture of the lens?
f62 wide open at 4x magnification.
8x10 at 4x conjures the notion of 'something special' not spoiled by some diffraction or vignetting. I'd be interested in seeing what you do with it.
Any new project will have to wait to the New Year!