Probably you know this very simple FF / BF Fine Tuning method:- Put your camera on a sturdy tripod. In live view and a comfortable magnification use manual focus to fine tune the focus on a suitable object. Now change over to AF and let the camera auto focus on the same subject. If the lens / camera combo is perfect, that is there is no FF or BF, then the lens focus ring should not move.
Depending upon the movement to the left or right, use the camera's fine tuning function on a trial and error basis till there is no movement of the focus ring. Zoom lenses are particularly notorious and some may display both FF and BF at various focal lengths. That is the cams in both the zoom and focus rings have excessive play or a lens element is loose in its mount causing it to move or jump. I normally tune my zoom lenses at the "most used" focal length. So for the 55-300mm it is at 300mm. Some Photographers choose the "Buddha's Middle Path". Thanks for reading. Bipin. Amateurs worry about equipment, professionals about time & masters worry about light. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
