Thanks for the replies. No I haven't adjusted the Diopter but that wouldn't help as I mean the Viewfinder is capturing softer images using autofocus than Live View when I review my images on my big computer screen. I have not yet applied any AFMA as I thought this would not improve the disprecancy between Viewfinder and Live View but having just discovered that AFMA affects only the Viewfinder or Quick Mode and not Live View, this might be a way of reducing the difference in accuracy between the two. The difference is most noticeable on the wide end so might just require the wide end adjusting. Shouldn't really be necessary though ideally. Also I believe the recommended testing distance is 50x the focal length if possible?
Never used Reikan Focal. Can anyone tell me how much it is to buy and how difficult it is to use? How does it work? Think I should give it a try.
Does the fact that I can get reasonably sharp results via Live View mean the inaccuracy is down to my camera and not due to any fault with my lenses?
Generally, the way to quickly tell if you need to fine tune your lens autofocus is to compare live autofocus and phase detect autofocus. Live Autofocus uses contrast detect which adjusts the focus to give the highest contrast image. Its slow, but fairly accurate.
Phase detect is much faster, but slight errors in the camera body or lens can affect sharpness, and, if the body is in error one way, and the lens is in error the opposite way, then the errors add up.
This is a consistent issue with wide aperture and long telephoto lenses, and Sigma lenses seem to particularly generate a lot of complaints.
The first thing I do with a new camera body is to run the AFMA adjustment with all my lenses. Each body is slightly different.
Neuro had it right!