I'm new to film photography and having received a Canon EOS 750 as a gift to get me started I set out with the Canon EF 100-200mm 1:45 A lens just to take photos and see how they came out. I'm puzzled with the result after using the recommended DX coded film that came with it (ISO 400). I had the images developed and scanned to a CD so maybe it's the scans combined with the grain? My question is this: what causes a lot of grain in film photography? Everything was in focus, it was a partly cloudy day, there really aren't any settings to play with on the camera, thoughts?