Looking for info about this lens i.e. image circle, front filter size, etc.
Looking for info about this lens i.e. image circle, front filter size, etc.
You may be able to find the info here. Scroll down until you find the Caltar lenses
http://www.cameraeccentric.com/html/info/calumet_2.html
Nice link! No direct reference to image circle but "it covers an angle of 56 degrees wide open and 64 degrees as the lens is stopped down." What is the method whereby one can figure out the image circle with that information?
In Excel. circle covered = focal length*2*TAN(RADIANS(angle in degrees/2))
"I was told there would be no math."
First one to name who said this and in what context wins.
Oh, and thanks Dan.
Although it doesn't say it in the catalog referenced, those coverage angles do not apply to the 20" f7 Caltar, they are specific to the shorter 4/3 Tessar-type Ilex-Caltar lenses. The 20" f7 Caltar is not a 4/3 Tessar-type. Several years ago when I wrote an aritcle on Caltar lenses for View Camera magazine I discussed this lens with Lynn Jones. I'll have to double check my notes, but from memory, according to Lynn the 20" f7 Caltar is a 3/3 triplet design with 35 degrees of coverage, which equates to an image circle of about 320mm - enough for 8x10 with small movements.Originally Posted by Thom Bennett
Kerry
Kerry, thank you for that info. Extremely helpful! I'll look through my back issues of VC for that article.
Thom,
You're welcome. The article is in the May/June 2003 issue of View Camera. My recollections above were correct (3/3, 35 degrees, 320mm IC).
Kerry
In a Burke & James brochure the lens is listed with a 58 degree coverage and as a lens for the 11x14 format.
Mine which is a late version with high serial number have the exact same reflections as my 375mm f6.3 Caltar
It is possible that the lens was born as a triplet and later changed but some at least are Tessars.
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