Re: I.R. Metering - Step up to the challenge

[phillip geller <filje@xxxxxxxxxxx>]

danzig@xxxxxxxxxxxxxx wrote:
> 
> Hi :)
> 
> The title must be confusing some of you. Let me explain it as
> clearly as can be, it quite simply means,
> 
> that I intend to make an IR sensitive meter.
> 
> It's irritating not being able to use convinient TTL metering for our IR
> imagery,....
I have found that  a cds metering cell is more sensitive
to IR than a silicon blue cell mainly because the silicon
cells have greenish colored IR blocking filters put on them.
It seems like you would want to do incident  or area-average 
reflected metering instead of spot. 
When you spot meter foliage through an IR filter, is the
bright foliage inflating the meter reading? Is the e.i.
of the film adjusted to compensate for this?
This has been a question which I posed  some time ago and 
received no replies.

Something to consider if you buy a minolta incident type meter:
They come with an accessory jack on the side. You
could experiment with plugging in different photocells
and figure out what works. (the silcon cell in the meter
has an IR blocking filter which decreases it's sensitivity
to IR but it will still see through an #87).
Also, the dome is removeable and you could fit a gel underneath 
it or get the spotmeter accessory and filter it.
Phil

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