Re: Exact fl of lenses... 220 VR

[ADavidhazy <ANDPPH@xxxxxxxxxxxxxxxxxx>]

> The fl in the roundshot is the only variable given to the user to effect the
> horizontal stretching and compressing.  The more stretched or compressed an
> image, even to a small degree, the less sharp it is....

OK, what you are talking about is NOT a change in the focal length of the lens
but a way to "trick" the camera into pulling more or less film through it per
360 shot (or fraction thereof). Sort of like using a "EI" with film instead of
Film Speed.
                                
So, the result of all this is that the camera does not pull the same amount of
film through it regardless of the exposure time you choose. Unfortunately this
is not a fault of the lens but the film transport mechanism or its control. The
reason for this is that it SHOULD be the same regardless of exposure time but
it seems that for your camera at least there is an unwelcome change.

I am not sure of this but if the slit size remains constant and the camera
changes exposure time by changing the rotation rate then I could understand a
change (not expect it but at least understand it). OTOH if the expusure time is
adjusted by changing slit size but not rotation rate then I don't see where the
error would creep in.

Seitz would be the most appropriate or logical people to answer this question
(as to why the camera draws different amounts of film through it per revolution
/ exposure time change).                               

Anyway, good luck ... I'm outa here!

andy

Andrew  o o  0 0 o . o  Davidhazy, Imaging and Photo Tech
         \/\/\/\/\/\/          http://www.rit.edu/~andpph
__________|        |_____________________________________