> ----- Original Message -----
> From: Mafud
> Subject: Re: Fast film to go with Porta 160
>
> > *("Rating" film is a slide/B&W technique).
>
> << Could you expand on this thought please? Are you saying
that people who
> shoot colour negative films are sloppy about technique?
> Bill >>
>
> I said nor inferred no such thing.
<snipped for brevity>
Gotcha. My concern with box speed ratings on any film, be it
slide, B&W or C-41 is that it only works under a specific set of
circumstances, specifically the circumstances used for the ISO
testing procedure. If my meter happens to not agree with the ISO
standard (I have over a dozen working camera meters, no two are
quite in agreement, and I cannon confirm that any agree with the
ISO standard), or if my shooting conditions differ from the
bench testing procedure that the ISO rating demands, then I
might have to ignore the box speed and choose a speed which
works better for me.
What this means in my world, is that if I am shooting Portra 800
(as fine a fast film as you can get, BTW) with my LX, then I
need to "rate" the film significantly slower than 800. This is
due to loss of speed caused by lack of spectrum for the film,
and increase of meter sensitivity caused by a deficiency in the
LX meter (it isn't colour blind).
I don't think "rating" film is just in the domain of the slide
film or B&W shooter. I think it is prudent to look at the
technical quality of ones work, with an eye to increasing or
decreasing exposure depending on individual circumstances, no
matter what film type is being used.
A blanket statement such as "shoot <insert film type here> at
box speed" isn't valid unless all you shoot is ISO reference
charts with an ISO calibrated meter. Otherwise, it is prudent to
keep ones mind open to the reality that one might have to make
adjustments. I suspect you knew that.
William Robb
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