Re: Exposure (was: Rangefinder etc)

[Willem-Jan Markerink <w.j.markerink@xxxxx>]

On 18 Jul 96 at 21:05, Robert Long wrote:

> I'm having a lot of trouble reconciling any of this with what I read
> in the instructions packed with my current roll of HIE.  The roll was
> purchased recently but the sheet's revision date is 7-83.  Is that
> really current?

Yep. No changes for precisely 13 years. 
But one cannot say it is an unlucky birthday, with this list 
launched!....:-))))
 
> The sheet specifically says that the ISO 80 speed is for use *without*
> a filter and that if you are using the recommended Wratten 25 filter
> you should set the meter for ISO 50.  That is less than a 1 stop
> difference, but of course the Wratten 25 presumably passes the entire
> IR band with little attenuation, so it would only be visible
> wavelengths that would suffer the usual filter factor.
> 
> Again, in giving recommended settings without a meter, the sheet shows
> a 1-stop difference between the Wratten 25 setting (1/125 at f/11) and
> that for no filter (1/125 at f/16).  This doesn't sound like ISO 400.

Nope, but taking pic's without at least a 25 filter is wasting film.
And for metering through such a filter, 400 ASA on the camera often works.
Darker filters screw up internal meters, often due to IR-block 
filters for both AF and AE. External meters however still work with 
dark filters; my Gossen Sixtomat Digital is almost on spec for every 
filter up to 87C. So 400 ASA is my holy starting point!....;-))

--
Bye,

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The difference 
between men and boys
is the price of their toys

<w.j.markerink@xxxxx>
[note: 'a-one' & 'en-el'!]