Hi all I was looking to increase my camera bag by buying a sigma 300mm lens for my nikon D40, when I bought the camera I was advised to buy the HSM lenses(which I believe stands for high speed motor
) but can't really afford to spend that much at the minute and was wondering is the normal sigma 300 just as good.
My main use would be for athletics photos in track and field and cross country.
any advice welcomed
thanks