Omicron-EL lenses feature eight precision diaphragm blades,
producing unsurpassed linearity of light trans- mission, vital for
professional print quality. Pin-point detents at click stops
permit easy "nulling" with analyzers, at
mid-aperture settings for precise ex- posure. On 105mm and
135mm lenses apertures down to f/45 may be selected. This is
a significant advantage when printing at small magnifications, or
with exceptionally thin negatives.
All Omicron-EL lenses have
a standard Leica-type 39mm screw mount, and front threading for
40.5mm lens ac- cessories. Two engraved aperture scales permit
full visibility at any orientation on the lens mount or board.
short back-focus design (flange-to-film distance) permits con-
venient use in turret mount enlargers, such as the Omega and Super
Chromega Dichroic D-6.
metal barrels are precision- machined and assembled, and have a
satin optical black finish with large white f/stop numerals.
Each lens is supplied with a mounting ring for lens installations
on unthreaded lensboards.
Every precision enlarging
lens is com- puted to perform optimally at a specific range of
magnifications. The Omicron- EL 50mm f/2.8 is designed for 2x to
20x magnifications; the 75mm f/4.5, 90mm f/5.6, 105mm f/5.6 and
135mm f5.6 are designed for 2x to 10x mag-nifications.
All Omicron-EL lenses may be used at all
apertures. However, the extra fast aperture of the 50mm
f/2.8 is recom- mended for focusing, with f/4 or smaller aperture
used for the exposure.