I saw my parents and brother over Chrismakwanzakah (well, mostly Christmas, in this case) and I took some shots during my visit. As it worked out, I took 44 shots and I’ve posted six of those. (Ok, laugh it up, fuzzball. Yeah, I know it’s March.)
I like to post just those shots that I’m happy with, so it’s par for the course that I end up posting fewer shots than the number of times I happened to have hit the shutter. Still, I usually aim for a higher ratio than this. What happened, as I discovered, is that while some people can hold hold a shot at 1/30 of a second, well, I’m apparently not one of those people. Candid shots are my bread-and-butter and hand-holding the camera goes right in line with that.
You may have heard that old adage about taking 1/ focal length to estimate the minimum shutter speed at which a handheld shot can remain acceptably sharp. (For instance, according to the adage, an 80mm focal length would need at least a 1/80 sec shutter speed in order to have a good chance of being sharp.) That’s said to be true for 35mm film, but the math does need to be updated a bit for digital cameras. Due to their smaller sensors, the “1/ ” part needs to multiplied by the crop factor of the camera (which is typically about 1.6 for Canon bodies and 1.5 for Nikon bodies).
Since I was shooting most of the time with my 50mm lens, the rule would suggest that I’d need a shutter speed of at least 1/75 sec. in order to get a good chance at a sharp image. Well, with the caveat that everyone is a little different — and some people may be able to hold a camera more steadily than I can — I can confirm that the rule is a pretty good guideline. Or, put another way, that would explain why the dozen or so otherwise-good shots (that happened to have a shutter speed of 1/30 sec.) didn’t have the sharpness I was looking for.
If I’m in a similar situation again, I think I’ll try increasing my ISO speed; most of my not-sharp shots were taken with an ISO of around 200-320 and there probably wouldn’t have been much to lose if I had increased the ISO to 400 or even 800. (Since doubling the ISO value captures twice as much light, those forget-about-it shots at 1/30 sec. might have been saved by a 1/60 sec. shutter speed.) I’d probably hesitate to use ISO 1600 if I could help it (as that’s when digital noise can start getting in the way), but from what I’ve read, most modern DSLRs can handle ISO 800 with only trivial (if any) levels of noticeable noise.