Re: Relationship between IR focal length adjustment and foc

["Sandor Mathe" <sandor.mathe@xxxxxxxx>]

> From:          George L Smyth <GLSmyth@xxxxxxx>
> Rolland Rainbow Elliott wrote:
> > 
> [clip]
> > I agree with your comments George and I rechecked the instructions that came
> > with my Sigma APO 70-210 f/2.8D Nikon Mount lens. However the instructions
> > still state that no IR correction is needed at the longer focal length of
> > 210mm, only at the 70mm end.  I find this very interesting.
> 
> I can only guess that this lens has APO correction into the infrared at the far end
> of its focal expansion(?).
> 
> george

I think it is equally likely that it is a typo or mistranslation in 
the "booklet".  The Minolta, Canon, Nikon instruction books that I 
have seen have been quite good, I have seen some obviously 
Japanese-original-translated-to-English instructions that were not so 
good (to be kind).  Is there anything else in the booklet that is 
badly translated?  I've never read a Sigma booklet though I do have 
one of their lenses.

Sandor Mathe  -- sandor.mathe@xxxxxxxx
(905) 670-1225 x333  --  FAX (905) 670-1344
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