Hey Pentaxuser. I consider the R72 to be have a filter value of 5 so I aim for... ISO 2.5 with the filter; you really need a tripod for doing IR with this film. I find this a plus, as I often convince myself I can hand hold shots Rollei IR 400 film for IR shots, when a tripod is the right answer for both film speeds with IR.
I was afraid you'd say this. I keep hoping that someone will reply that Rollei 80 can be shot while handheld( looking for the Holy Grail, I think, it is called
) but at EI 2.5 I agree that hand-holding is out of the question. However there is a bit of hope in that if a factor of 5 applies to Rollei 400 then this reduces it to 12 and with sunny f11 rule( U.K. latitudes) and a wide angle so DoF is less restricted a hand-held shot might be possible with f 8
Thanks for the info
pentaxuser