The 70-300 is f4/5.6 IS. Very interesting replies. I am using a Sigma 18-200 non IS lens and though I try as much as I possibly can it is just all but impossible for me to get a steady image though I am doing what is advised and use f8 on Aperture Priority selection. This is for very slow or stationary subjects, well, aeroplanes, really, you know yourself
. It would be more understandable if the quarry were moving quickly but they are not. It is galling and I can understand now why I have stayed away from taking photos for so long. Not much fun yet anyway.