Re: Which Nikon ED lenses dont' need focus correction?

["Willem-Jan Markerink" <w.j.markerink@xxxxx>]

On 17 Jan 01 at 8:34, Rolland Elliott wrote:

> I ran across an interesting statement in the Nikon instruction manual for 
> the manual focus Nikkor 200-400mm f/4 ED zoom lens.
> 
> It states that some Nikon "ED" (ED stands for extra low dispersion glass) 
> lenses do NOT require focus correction in the IR spectrum.
> 
> This lens was manufactured around 1984.  It DOES require focus correction.  
> However I am curious as to which Nikkors don't. Anyone know?
> 
> I've asked this question several times on the Nikon mailing list and no one 
> seems to know. I also called Nikon USA and they were clueless.

Don't expect better answers from Canon....it's simply not tested.
The best thing from Japan is the spectral chart from Mamiya for their 
RB/RZ apo lenses....but even these don't run into the 900nm-ish 
region....
Hope to intensify my contacts with Canon soon, and get more testing 
privileges for their high end stuff....the only aspect of their 
CPS-membership that interests me....:)) 

--                 
Bye,

Willem-Jan Markerink

      The desire to understand 
is sometimes far less intelligent than
     the inability to understand

<w.j.markerink@xxxxx>
[note: 'a-one' & 'en-el'!]
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