It's so obvious but it took me a while to find it out :)
I used to do infrared photography with my Nikon F4 SLR. It works fine but it’s a kind of a mess always taking of the IR filter to focus and putting it back on. That’s a problem I don’t have using a Pinhole cam, but as you know it took me three rolls to get the exposure right. Now I had the simple idea of mounting an IR filter on a rangefinder camera. Well that’s nice. You can focus without taking the filter off. Everybody already knew that one… but now I discovered it myself.
By the way the Efke 820aura is better then the Rollei and Ilford SFX to do IR. But it’s real light sensitive you have to load it almost in the dark. The others you can load normally.
This was my first try, just to see how the film performs. Now I am going to try to be creative with the Efke film :)