Originally posted by newarts I've photographed a projected dot from a laser mounted to the camera at various shutter speeds but my results are inconsistent.
Mounted to the camera?!?! Would that make SR unnecessary, since laser pointer follows the camera movement (shake). So if SR kicks in it would in fact make the things
worse, not better, and results would be confusing and certainly inconclusive.
I think this is not a good test. Laser pointer should be fixed and mounted separately from the camera. And in fact, you don't need a laser pointer at all, just point at anything.
A few notes on SR:
Keep in mind that SR will not work miracles. It will just give you a few stops advantage over the recommended "safe" shutter speed depending on the focal length. The old guideline for deciding a "safe" shutter speed for certain FL (focal length) was 1/FL or faster. For example, if you are using a 100mm lens, that would be 1/100s (in reality 1/125s) or faster. This still works for me regardless of 1.5X crop factor, but you may adjust it to something like 1/(2*FL) just to be on the safe side.
So if with 100mm lens one can expect most shots to be sharp at 1/125s, with SR what would remain true for shutter speeds of up to 3 stops slower, that is, 1/15s. For a 28mm lens without SR it would be 1/30s or faster and down to 1/4s with SR. Slower than that and risk of getting blurred results will increase.
Back to your test: fix the laser, and if you are using for example 100mm lens take a series of photographs of the target dot at 1/15s with SR on, then take another series with SR off. You should get more clear shots with SR. And remember, this is all about probability: even without SR you may still have a few sharp results. Likewise, even with SR you may get a few bad ones. It also depends on how steady you can hold your camera. Just do not expect perfect results from SR.