Re: (Fwd) Re: Reciprocity failure was: Re: How can I recognice 'ol

[George L Smyth <GLSmyth@xxxxxxx>]

Willem-Jan Markerink wrote:
> 
> Note that stopping down is worse for IR than for visible light, as
> diffraction is twice as bad with 800nm as with 400nm. So don't overdo
> it....f8-11 should be the limit I guess.
> 
> I know some people disagree on this, but I have even seen this info
> pop up in Russian(!) literature about IR-photography. I read it first
> in Guenter Spitzing's book though, in both his editions.

I'm not sure how anyone could disagree with this.  We are talking about
physics here, and the fact is that the longer wavelengths are affected
by diffraction to a greater extent.

george

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