Clive Russ, Cooke XVa Triple Convertible lens purchase

Cooke XVa Triple Convertible multicoated lens

Cooke XVa Triple Convertible lens in barrel

No longer available in barrel (no aperture iris)

Cooke XVa in Copal 3 shutter

PRICE:

DESCRIPTION

Filter Size
77mm screw in Front Cell
62mm screw in Back Cell
62mm screw in Gold Ring (shutter front)

A few photographers have bought two lenses and one shutter with the idea of extending the focal length range. Two 19" (476 mm) elements make a symmetrical lens of 273 mm, and two 25 1/2" (646 mm) elements make a 368 mm focal length lens. The sequence is 273mm/10.75" ƒ/5.6, 311 mm, 368mm/14.5" ƒ/8, 476 mm ƒ/11, and 646 mm ƒ/16. These focal lengths cover 8x10 inch format with generous movements. This lens was not designed for 11x14 inch format, so the shortest focal length may vignette, but all the rest cover.

The COOKE XVa is a lens made in small quantities, to very high standards, with multicoated lens surfaces and full COLOR CORRECTION. It makes a brilliant image for color or B&W films and digital sensors. The use of high refractive index lanthanum glass in two of the elements allows better corrections and flatter lens surfaces. This also makes the quality of the image from single elements about five times as good as the original series XV. There is no need for yellow filters, minus blue, to sharpen the image in black and white. It projects a sharp, high resolution, high contrast image at f/6.8 on 8x10 inch film. The individual elements are ƒ/11 and ƒ/16. They too project a sharp color corrected image on 8x10 inch format film. The Copal No. 3 shutter fits on a 4" Linhof Technika type lens board. S.K.Grimes makes some very nice inner lens caps which are very useful when one element is removed from the shutter.