Quote Originally Posted by DWThomas View Post
Don't do it! A 760 nm filter on the Rollei stuff needs about 12 or 13 stops additional exposure. Bigger numbers are farther into IR, the film sensitivity is already rolling off at 720 and drops like a rock beyond that. And to your question about my statement above, guess I would have been clearer had I said increase exposure by 6 stops. You could set your meter to a lower ISO. I was using a Digisix that only goes down to 6 -- and if I used the 760 filter, I need about 0.25!
OK, I think I understand so the 92 filter is best as I risk not exposing the film at all with the 93 because it begins at 800nm and some of the Rollei film doesn't even reach that high. OK, and I will set the meter to around 6 ISO and then bracket +/- one stop on either side (3 ISO and 12 ISO) and hope for the best haha. I was doing something similar when I was shooting my 1947 expired Verichrome... that was also 0.75 as an estimate of the EI I would have to use based on age... haha

I like crazy films but they make me crazy too!