ALPA back adapters for Roll-Film Backs Mamiya RB and Horseman
ALPA has been producing the two adapters for roll film backs from Mamiya (for the RB) and Horseman since their introduction in 1998. Both roll-film backs follow the Graflok 23 standard. But as their flange distances differ by about 15 hundredths of a millimeter, ALPA offers two dedicated versions for the Mamiya RB and Horseman.
Besides, the Mamiya MA adapter features the rear release button that triggers the automatic film advance on the RB motorized variants. The adapter is compatible with all manual and motorized backs for 6x4.5 to 6x8. We have found the best flatness with the motorized backs for 6x7 and 6x8.
The Horseman adapter HO allows the popular 6x7 and 6x9 backs from Horseman and ArcaSwiss (identical in construction). By the way, the 6x9 format here is around 56x82 mm, whereas ALPA's own ALPA/Linhof 6x9 back exposes 56x84 mm.