Depending on the lens you have for the Rollei, you may not be able to project your 35mm as large as you'd like because the lens will be too long. I don't know what lenses they made for the Rollei- if it was meant to be a dual-purpose projector, I would assume they have shorter lenses for 35mm along with the longer lenses for 2 1/4. I know the Hassy PCP-80 had three lenses for it, but they were all for 2 1/4 slides.