Re: Leitz 160vs170mm questions about DIC/ICT

Theo Griep writes:

How can 160mm objectives be used on a 170mm microscope?

A microscope objective is a lens with a focal length and cardinal points,
like any other lens, and the Gaussian law 1/f = 1/v + 1/v' still applies.
The tube length specification (160mm, 170mm, infinity, etc) is simply the
conjugate distance v' for which the aberrations are best corrected, nothing
more. You can move the image from v' = 160mm to v' = 170mm (or vice versa)
by adjusting the object distance v by the proportionate inverse, as per the
equation above. Whether such a slight change increases aberrations to a
significant degree depends on the characteristics of the optical design.
.