Re[3]: INfrared Basics

["Peter Badcock"<pbadcock@xxxxxxxxxxxxxxx>]

Greg,
        what kind of filter do you place over the front of your lens?  You need 
one to filter out what ever visible light you don't want to reach the film, 
since in HIE's case it is sensitive to most of the visible spectrum as well.

You have two main choices for metering a scene when using a filter over the 
front of the lens, You can either meter with it on or off! Pretty simple huh?  
Well, of course if it is on the lens it has to let enough visible light through 
to register on the camera's metering system and to allow you to compose the shot
of course.  I think a popular filter used when metering on the lens is a #25 (or
25A?)  If you meter with the filter on the lens, composition is easy, if you 
meter with it off, then you need to keep the camera steady while you screw the 
filter back on, often a tripod helps a bit here.

I use a Hoya R72, which is equivalent to a wratten '89B'.  One can just see 
through it with the naked eye, but it is way too dark to have on the front of 
the camera when metering.

I'm not sure what the spectral sensitivity of camera meters to near IR is.  I 
guess it would vary between camera, this is why the experiments you do with your
setup will be unique to that particular configuration.

Personally though, I haven't shot colour. so I can't give you any hints on that.

happy shooting,
regards
Peter B.


______________________________ Reply Separator _________________________________
Subject: Re: INfrared Basics
Author:  <infrared@xxxxx> at INTERNET 
Date:    19/2/98 9:26


Thanks for the reply Peter,
     SO are you saying that if I set my camera to say 200 ISO and bracket
off the reading from the camera meter I should get good results.I was under 
the impression that the metering of the camera was not the same for 
infrared-not able to read infrared rays.Im gonna try color for the first 
time this weekend(weather permitting)and hope to have better results.Ill 
keep you posted.Thanks again.
GREG


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