Not all problems are what they appear!
(Problem Six)
Back at home I decided to look more closely at the problem of the occasional unexpected blurred pictures that were cropping up when using the newly acquired Sigma 70-300 APO lens. Whilst looking at the results of some macro work on these young copper beach leaves, I realised that the common factor with the blurred images was a shutter speed around 15th of a second. This is the speed where mirror slap on a reflex camera causes camera shake the most - except that in the case of the macro work, the camera was on a very firm tripod! I did some tests (see the RESULTS)