Joseph Albert wrote:
>
> After thinking more about the notion that film resolution is affected
> by aperture, I've concluded that it seems to be a misguided notion.
>
> When talking about the effects of combining film and lens into a single
> system we talk about film resolution as some property exclusively
> of the film and measured independent of anything else (and independent of
> any lens) and aerial resolution of the lens as being independent of anything
> else, including film.
>
> So, to talk about the effect of lens aperture on film resolution is
> talking about some property of the combined system of lens + film,
> whatever that might be, but it isn't a property of film to the exclusion
> of all else including the lens.
>
> In other worse, I do believe that aperture affects on-film resolution in
> the combined system, but it is outside the defining scope of film
> resolution to talk about the affect of an aperture.
>
> j. albert
>
I have not thought a lot about this, but film has one property,
where the lens aperture has some effect: The light sensitive emulsion
has a finite thickness.
We tend to think of film as having zero thickness, while the emulsion
in reality is some small fraction of a millimetre in thickness. To
get a sharp picture you need "depth of field" (or whatever) to cover
the thickness of the emulsion. In practical terms this translates to
the effective resolution of the film is depending on a combination of
focal length and aperture.
While I can not quantisize the effect right now, I am certain that the
effective circle of confusion becomes smaller with smaller aperture
and thinner emulsion.
Regards
Lars
--
Lars Haven <mailto:lhaven@xxxxxxxxxxxxx> aka <lhaven@xxxxxxxxxxxx>
"When writing about women, one must dip one's pen in a rainbow"
D. Diderot
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