These lenses are intended primarily for making color transparencies with Kodachrome Professional Film or color separation negatives. Although designed especially for color work, their uses is by no means limited. They are suitable for all types of photography. When used at maximum aperture, the image size on the ground glass should not be larger that about one-third the subject size. At even small apertures these lenses perform satisfactorily for almost all types of work, even at lens-to-subject distances giving about 1 to 1 images size.

These lenses are exceedingly well corrected for all lens aberrations such as coma, astigmatism, curvature of field, and spherical and chromatic aberration both lateral and longitudinal. The inner air-glass surfaces are treated by a special process which reduces reflections. This increases shadow detail and brilliance in black-and-white and color purity in Kodachrome pictures. Under certain conditions, lens treating adds to the effective speed of a lens.

The Eastman Ektars f /6.3 cover at full aperture and angel of 53° and at small stops an angle of 64°. For example, the f /6.3, 14-inch lens covers adequately the recommended negative size (8 x 10 inches) at maximum aperture with allowance for full use of the rising and falling front and swing back. At apertures below f /16 its 64° covering power permits its use on an 11 x 14-inch camera, but without allowance for swing back or rising and falling front.

These four Ektar lenses are available in shutter or in barrel. The use of these lenses for enlarging or projection printing is not recommended.

Kodak Reference Manual/Lens, Rangefinders and Shutters section,
© 1942, 1945