1. Test shots with both versions of Mamiya ZD back

Strange effect of purple spots - depending on increasing exposure times - in dark areas on pictures shot with ZD back and ZD back DB.

Bild in Lightbox öffnen (open image in lightbox). Mamiya ZD back DB (left), ZD back (right)
Bild in Lightbox öffnen (open image in lightbox). Mamiya RB67 Pro SD with ZD Back DB
Sekor C 4.5/50mm
ISO 100, t=7", F/11, YB401 
 
Bild in Lightbox öffnen (open image in lightbox). Mamiya RB67 Pro SD with ZD Back DB
Sekor K/L 3.5/127mm
ISO 100, t=5", F/11, YB401 
 
Bild in Lightbox öffnen (open image in lightbox). Mamiya RB67 Pro SD with Standard ZD Back
Sekor C 4.5/50mm
ISO 100, t=7", F/11, YB401 
 
Bild in Lightbox öffnen (open image in lightbox). Mamiya RB67 Pro SD with Standard ZD Back
Sekor K/L 3.5/127mm
ISO 100, t=7", F/11, YB401 
 
Bild in Lightbox öffnen (open image in lightbox). Picture noise at exposure times longer than 4 sec.