"Mr. Bill" wrote:
>
> Back to the discussion where someone proposed that the size of the print
> (reproduction ratio) would have something to do with apparent depth of field.
>
> That doesn't seem to be the case. Obviously the size of the print has
> great effect on the apparent graininess (pixilization if you go digital)
> but the effect of depth of field is the same. Try this with your slide
> projector some time.
>
> Apparently the depth of field is set when the real image is exposed on film.
>
> Mr. Bill
The depth of field equation also includes viewing distance from the
final print size (actually, the equation doesn't--it is the calculation
of the acceptable size of COC that does, and this usually take a priori
from Leitz, et al.). With projected slides, your viewing distance is
usually further, allowing larger COCs for the same apparrent dof.
Personally, I agree with you on the DOF being set at the film, because
my max print size usually follows the size of the film, and any smaller
prints just have more apparrent dof (though not much more due to the
decreased assumed viewing distance).
Mike
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