This question got me thinking. My IR experience is limited to SFX200 so...
If I'm using an IR filter, all wavelengths below 720nm will be cut.
SFX200 is sensitive to 740nm, while Rollei IR is sensitive up to 820nm.
So, in comparing the films with a theoretical scene, the SFX will be capturing a slim range of only 20nm, while the Rollei IR will be able to capture a larger range (100nm).
What differences should one expect to see in the final negative?
For example, would one show brighter foliage than the other? Clearer skin and darker eyes in portraits?...etc...
Possibly answered a part of this question already, but adding it to the question for confirmation by more science-minded folk:
This paper by UC Davis shows a rather extreme change in reflectance for healthy leaves between 700 and 800nm...
Given this, the Rollei IR would most likely capture an overall "brighter"* looking foliage and should be able to do so at a faster exposure time than SFX...no?
* I realize that brightness is subject to exposure - what I'm thinking is, if there is, overall, more reflectivity to the subject, the whole area would thus appear brighter - similar to how a white T-shirt would compare to a gray T-shirt with white writing.