ALPA products are quality products manufactured with minimum tolerances. The standard is 1-2/100 mm deviation. However, ALPA cannot influence the sensor position of digital backs. However, a correct back focal length is essential for a reliable infinity adjustment.
To correct any deviations from the norm, ALPA introduced shimable adapters in 2004. Each adapter can be optimized in the range of +/- 3/10 mm in 1/100 mm steps utilizing shims supplied with the unit.
Another advantage of this system is that professional users with several digital backs will appreciate it: Since deviations can often occur from back to back, these errors are elegantly corrected with an optimized adapter for each digital back.
ALPA offers the individual adjustment of your adapters when you visit us in Zurich.