Re: APO and IR

[Vaughan Bromfield <v.bromfield@xxxxxxxxxx>]

At 01:44 AM 12/9/96 +0000, you wrote:
>On  8 Dec 96 at 22:08, WJM wrote:
>

>This is also a nice way to qualify the too often used APO: if it 
>still requires IR-refocus, then its APO qualities are minimal.
>

Ahhh sorry to be pedantic, but APO actually has nothing to do with IR. It
was intended to refer to lenses used to make colour separations for
printing, where Red, Green and Blue images are created. The high correction
is required to ensure the rgb images are exactly the same size, otherwise
the registration of the plates will be poor.

Now an APO lens may have have a design that happens to imporve the IR
capability, but strictly speaking it is coincidental and may possibly vary
between individual lenses.

Is that why Hassy coined the phrase "super APO" ?

Vaughan

Vaughan Bromfield
Information Technology Division
University of Technology, Sydney
1 Broadway
Broadway NSW 2007
Australia

v.bromfield@xxxxxxxxxx

phone: + 61 2 9514 2176
fax:   + 61 2 9514 1169


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Topic No. 3