Infrared Exposure Meter?

[Helen Bach]

There were instructions about how to modify a Pentax spotmeter in an old issue of Photo Technique. The idea was to set the long end of the meter's sensitivity to the long end of HIE, using a Melles Griot interference filter, then add whichever visibly opaque filter that you were going to use over the camera lens - all this happens right in front of the meter cell so you can still see through the meter. I modified a Pentax and a Sinar Booster that way. All my old copies of Photo Technique are in storage, so I can't look the article up. I still have some of the Melles Griot filter somewhere in a drawer - but it isn't correct for the IR films available now, of course. It was quite easy to cut down - just like very thin glass, protected with tissue paper when snapping along the scratch.

[Old-N-Feeble]

(filter at the sensor) "...so you can still see through the (spot) meter."

Ahh... why didn't I think of that? These days I miss the obvious all the time!

[nolindan]

I find just setting a plain-ole Sekonic 398 - the type with a selenium cell - to ASA 6 [well, ASA 12 and doubling] gives very good results with the near-IR films and a #72 filter.

If you want to you can meter through a #72 filter to get some idea of relative IR intensity. The 'blue' filter on a silicon photodiode isn't very good at blocking IR, enough gets through for the meter to register.

[Kodachrome25]

I have a David Romano meter conversion, works great. I had it made when I cleaned out Samy's of HIE and bought 50 rolls of Romano 70mm Aerographic re-spool from a private seller some years back. If IR is important to you like it is to me, the meters are worth it...

[dave]

I find just setting a plain-ole Sekonic 398 - the type with a selenium cell - to ASA 6 [well, ASA 12 and doubling] gives very good results with the near-IR films and a #72 filter.

If you want to you can meter through a #72 filter to get some idea of relative IR intensity. The 'blue' filter on a silicon photodiode isn't very good at blocking IR, enough gets through for the meter to register.

I also just use an ordinary meter set at ISO 12 and open up a stop. Converting a meter seems to me to be an expensive way around a simple problem.