Originally posted by sterretje
As I often forget about that, I have decided to leave it off till I really need it. With reasonable technique (regarding holding the camera steady when taking the shot) you should be able to take blur free pictures when the shutterspeed is shorter than 1/(FL*crop). So for 55mm, you should be able to leave SR off till the shutterspeed becomes longer than 1/(55*1.5) sec (about 1/90s) and for a 300mm it will be 1/(300*1.5) sec (1/450s). With good technique, you can probaly halve that.
Ever since the silent firmware updates for the K-7 an K-x in recent months, I've been able to take pictures at ridiculously slow shutter speeds lately with shake reduction enabled. I'm talking 1/6 second at 50mm with a steady hand, and 1/13 when I'm not being as terribly careful. Always waiting for the SR icon to come on, of course
Obviously, this is useless for action shots. You can't expect your subject to stand still long enough to get a good shot at 1/6 shutter speed.