Re: Different colors have different indices of refraction

[boblong@xxxxxxxxxxx (Robert Long)]

On Thu, 05 Dec 1996 03:44:59 +0000 (GMT), Hank Hogan wrote:

|camera lenses: the infrared light of longer wavelenght requires more
|distance to focus because it is refracted (bent) less than visible
|light,
|except of course, in the much maligned mirror lens!

Say again?  I assume you mean:

1)  much maliigned, because of the distracting circles that can be
created by out-of-focus highlights, and

2) that the *mirror* *part* of the path will work equally well for all
wavelengths, since no refraction is involved.  (Surely all mirror
lenses have front and back lens elements that do refract the light and
therefore do have a tendency to bend IR less than visible light, no?
Obviously, I own and use no mirror lenses.)

Bob Long
(boblong@xxxxxxxxxxx)

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Topic No. 5