Dear Dr. Singh, Since the lens seems to be heavy, I think using a tripod is indicated to minimize shaking that occurs when hand holding a camera without image stabilization. Unless you are solid as a rock steady, blurring of your image will occur especially at extreme magnification.
Does your lens require a particular aperture setting so you can use it fully automatically? Are all the settings in place to enable you to use the lens in full automatic mode? I am not conversant in use of Canon camera being a Nikon user. However, on my D70 camera body there is a switch to toggle between manual (M) and autofocus (AF). I find reading the manuals for both lens and camera operation invaluable at times like these in this discussion. Best regards, Joseph
