Attempting to gather any technical ideas about ACL flicker here. The prompt was some recent informal posts in the Fleamarket thread. I'll offer some introductory ideas then paste those... ACL Flicker. Introductory...what causes it? 1) Is it generic to ACL or is it a fixable fault? Are ther multiple causes? 2) On both N16 and some of the S16 conversions, is flicker caused by)?    - Mirror off position due to wider aperture?    - Mirror off position due to timing.    - Mirror off