Re: IR response of meters

["phillip geller" <filje@xxxxxxxxxxx>]

> On the other hand, when you slap an IR filter on the camera, the TTL meter
> is responding to something... perhaps the little bit of red, or some
fringe
> IR which you cannot see, but to which the meter has a bit of residual
> sensitivity?
I would agree


> If you think about it, no camera manufacturer is going to leave much IR
> sensitivity in the TTL meter, nor even a hand held. Otherwise, how could
> you ever hope to correctly meter a scene for color? (In an ideal case, the
> meter response would be exactly the same as the film... of course, this is
> only true in an approximate sense.) Any light source which is for some
> reason "rich" in IR is going to upset the total meter reading, and cause
> you to underexpose the visible light portion.


indeed, if the ir blocker isn't on over a ccd cell the red tones in a video
picture
are over saturated. cds cells are yellow green sensitive mostly as I think
are selenium.
another thing to consider about ttl metering is how that light gets to the
meter,
on canon, it goes through a beam splitter prism in the focusing screen, and
if
your eye isn't right up in the eyepiece as it wouldn't be with eyeglasses,
then light coming in through the eyepiece will inflate your meter reading.

phil




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