Re: Kiev fisheye (was: Re: IR spherical panorama)

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

On 18 Oct 00 at 1:57, Marco Pauck wrote:

> > Anyway, was the resolution test carried out with wide open aperture
> > or was this down a couple of stops?  With such a wide acceptance
> > angle, closing the iris may cause diffraction problems anyway -
> > comments?
> 
> I assume that these values are for a stopped down lens.
> Diffraction problems will not arise unless you stop down to, say,
> f16 or beyond.

But, with IR, diffraction is more severe, as it is 
wavelength-depending....:))
 
> > Finally, do you know the size of the fisheye circular image on 4x5 format?
> 
> Sorry, haven't measured it.

The minimum circle can be calculated easily: it's the diagonal of a 
6x6 frame, IOW the square root of (56^2+56^2) = 79.2mm.
For a 6x7 lens like the Mamiya 37mm it's (56^2+69.5^2) = 89.3mm 
(actual circle is 92mm, just to give you an estimate of calculus vs 
reality) 

--                 
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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