Re: question about ISO vs EI

[Clive Warren <Clive.Warren@xxxxxxxxxxxxxx>]

At 9:12 pm -0600 17/10/00, Christina Z. Anderson wrote:
>
>Ok, I got the following out of Paduano's book, and I just am puzzled:
>      "With no filter, Kodak has a suggested ISO of 80, and Konica of 32.
>With a no. 25 Kodak is 20, Konica is 8.  EI for Kodak is 200, for Konica is
>50-64, except under low light for Konica use an ISO of 100. "
>       How does the EI relate to this suggested ISO; do you rate the film in
>camera with the 80 or the 200?  Joe, I know you are on the list, so were you
>saying that Kodak says to use ISO 80, but most people use EI/ISO 200?
>Please explain.  I just cannot seem to get the bottom line of what the
>general rating of HIE and Konica is:  tell me if this is correct:  set the
>ISO in your camera to 200 (I am using a rangefinder, BTW which is not TTL),
>and open up two extra stops for the addition of the red filter, so, in
>essence, you are exposing the film with the filter on at 50.  Well, I did
>this with Konica, I exposed it with an ISO of 50, compensated with the 29
>filter factor of 3 stops so that I was shooting at an ISO of 6, and my
>negatives were basically bulletproof and unprintable.
>       I'm sorry I am so dense on this point, but the exposures on this forum
>have also run a gamut of 50 to 10,000 (even tho the last was thought to be
>impossible). Is it that all the adjusting comes at the development push/pull
>stage?
>       Thanx for dealing with my dull mind; I'll get it straight soon,
>hopefully, with your help!
>Chris


Hello Chris,

Exposure can be a confusing issue as there are a number of variables 
involved - the filter type, use of meters, development of film, time 
of day etc etc.

I have tried to give an independent guide to exposure in the Infrared 
FAQ (URL in sig. file). Using the information in the FAQ as a guide 
the only real way to calibrate your equipment is to test.

Sounds to me as though you have overexposed your Konica film between 
one and two stops.  Because of the inherent high contrast of the film 
some negs will look unprintable but can in fact be rescued with some 
judicious dark room work....


-- 
All the best,

              Clive   http://www.cocam.co.uk
                      Photographic Services, Filters and Equipment, Infrared FAQ
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