rapid rectilinear lens

Does anybody have information on rapid rectilinear lenses? I

understand the design is an early one (pre-1900) and that they degrade

in sharpness before they vignette. Any info on specific brands, focal

lengths, coverage, etc.? Also interested in specific info on elements,

groups, etc.

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Thank

Dave: According to a book I have, published in 1943, The rapid

rectilinear lens was designed in 1866 by Dallmeyer and at the same

time by Steinheil. It is a four element lens, with identical front

and rear cell being made up of two cemented elements. Aperature was f-

8 and the lens had a 50 degree angle of view. The article states that

above 50 degrees anastigmatism becomes unbearably great. The lens was

the first attempt to spherically correct a lens so that larger

aperatures could be used. At that time, f-8 was considered a large

aperature. I can't help with the specific brands, because just about

every company made the design, nor can I help with focal lengths. I'm

sure there are those on this forum with this information.

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Regards,

Weston used one when it had become outmoded by the latest soft-focus

lenses.

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It is fairly common for lenses of that vintage to have a wider circle

of coverage than is usable. Modern lenses are designed to vignette to

improve contrast that would be lowered by excessive internal

reflections, and to generally improve the sharpness specs of the lens.

If you prefer soft corners and wider coverage to less coverage black

corners, older lenses can be preferable in some respects to newer

ones.