
Posted: Sun Oct 18, 2009 9:17 am
There's two types of Roll film backs, the first fits Graflok type backs looks more like an RB67 back and are made to fit either a 6x7/6x9 camera or a 5x4 camera (they aren't interchangeable).
Then there's a second less common type, which looks quite different try a
Google image search.
The Sinar roll film holder looks more like a 5x4 Polaroid back the film spools sit at the end of the back allowing the holder to fit under the spring back lke a normal film holder. Calumet have some made in Holland

by Cambo but the prices are rather high $549.99 (US) upwards.
The disadvantage of these backs is the film has to pass 180° round a small roller and this can lead to film flalness problems when a film is left in the holder.
Your best option is look on a site like APUG or Large Format Photography, both have sales sections and Graflok backs appear from time to time. It's only a 5 minute job to change backs.
Ian