Focus Issues Bought myself a used Canon 70-200mm F4 L USM IS Lens but as yet I've not achieved a single Sharp image list of various settings tried attempts so far and still no joy very frustrating. I placed lens both on my Canon 20D & 40D still no
1,Tried faster shutter speeds & An array of F-stops (all within correct exposure) using inbuilt camera meter as well as Sekonic 758 dr 2,Live view x5 & x10 manual focus on my 40D 3,100,200,400,640 800 1600 3200 iso 4,Mirror lock up & cable release