Re: [OM] Seat warmer

[Fernando Gonzalez Gentile]

Found the plaussible explanation I should be looking for if I were awake 
_ thanks Chuck.

Fernando.

Chuck Norcutt wrote:
> Cat's pupils vary from round under low illumination to tall vertical 
> slits under bright illumination.  The vertical size under bright light 
> is about 12mm while human pupils reach a maximum dark adapted size of 
> 7mm and close down to about 3mm in bright light.  Where a typical flash 
> shot is being taken the human pupil might be 5mm in diameter and the 
> cat's be 10mm tall or over twice the physical vertical dimension. 
> That's problem number one.  The second problem is that the cat's eyball 
> is much smaller than a human's so the angle from the vertical edge of 
> the pupil to the retina is very much larger in the cat than the human. 
> To eliminate "red eye" in the shot for people or cats you need to have 
> the flash separated from the lens at a larger angle than that from the 
> pupil to the retina.
>
> The solution for shooting flash with the cat is to use much more 
> separation between flash and lens vertically and also to move the flash 
> to the side if you can to avoid that vertical slit.  I haven't done any 
> computations here but I suspect strongly that you'll have to get the 
> flash well off the camera to make it work.
>
> Dr. Flash
>
>
>   



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