Re: Exposure

[Cor Breukel <cor@xxxxxxxxxxxxxxxxxxxxxxxxxxx>]

.to add to the filter discussion (see below): I found this on the Web:

http://gaia.uc3m.es/~jmaw/photo/filter-data.html


A table with all different infrared filters (10nm intervals) filter
number, stability rating and 3 collums of wavelength, transmition,
density.


Cor


On Thu, 18 Jul 1996, Willem-Jan Markerink wrote:

> On 18 Jul 96 at 1:52, Vaughan Bromfield wrote:
> 
> > Kodak's data suggests ISO 80 for HIE. This refers to a hand-held meter, and
> > assumes a red or ir filter is on the camera lens. That is, don't add any
> > filter factor corrections to the ISO 80 reading!
> > 
> > For real-time SLR TTL metering, set the meter to 300 - 400 ISO with a red
> > filter. Or set the camera to 80 ISO and set the shutter/aperture without a
> > filter, then screw on the filter and expose.
> 
> My favorite way of explaining exposure is indeed starting with this 
> 400 ASA. Then adjust +3 stops for red, +4 for 87 and darker, and +5 
> for 87C.
> In the past several people have emailed me asking for the proper
> setting for the darker colors 87B and 87A. Regrettably, Kodak has
> skipped many of its IR colors (only 87 & 87C remaining I believe),
> so I am currently involved in a (too) long project having this color
> made in resin.
> 
> But I noticed from at least one bio that a 87B user is among 
> us....perhaps you could tell us the typical exposure for this filter?
> Would be very convenient if one could just add another stop, so +6 
> for 87B, and +7 for 87A. But the curve of the film's sensitivity 
> should tell me otherwise....it wouldn't surprise me if it is +8 and 
> +10....
> 
> BTW, anyone numbers on Konica with darker filters than #25?
> I once read that for practical purposes (read: not yet bulb setting) 
> #89B was the darkest usable color; but I also read about using #87, 
> ending up with fractions of ASA....;-))
> 
>  
> --
> 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'!]
> 

Cor Breukel 
http://ruly70.MedFac.LeidenUniv.nl/~cor/cor.html
cor@xxxxxxxxxxxxxxxxxxxxxxxxxxx