Originally posted by drabina It is the lock that's the problem. The only thing is that if the AF was faster, then it may lock faster and do not miss as many shots. It looks like K10D with my Sigma lens just hunts and is never able to determine when to lock the focus.
I did play with Nikon D40 at the store trying to focus on people moving and it looked like it was spot on. I had a feeling that AF knew which way to turn so I never had any back and forth AF action.
a couple points... most stores are lit much brighter than a standard house so I'm not sure that experience is giving you useful info. maybe bring in your camera to the store and do a comparison w/ both cams in a similar situation. I met someone at a store who I was testing a lens at so I did quite a few tests and focusing w/ the k10d in store lighting conditions was not an issue. ymmv, though...
at a family event I was at recently, I was sitting at a table w/ my cam on the couch when my nephew starting goofing off. my unlce's D70 was on the table, so I grabbed it and tried to shoot... it fired but was out of focus. of course, I've only used his camera for maybe a total of 15 minutes prior so I am not anywhere near comfortable using it so maybe I was doing something wrong.
at that same family event, my nephew began chasing my uncle around and my attempts to capture this w/ my k10d failed miserably. I was too close making the effective DOF really shallow and since they were moving, I'm not sure I had a chance. Using the DOF calculator, at f2.8 and 28mm from 4 feet...
Subject distance 4 ft
Depth of field
Near limit 3.7 ft
Far limit 4.36 ft
Total 0.66 ft
so a 6 inch movement, and I my pics were fuzzy. but if I was 10 feet away:
Subject distance 10 ft
Depth of field
Near limit 8.28 ft
Far limit 12.6 ft
Total 4.33 ft
but realistically, I'd have zoomed in, to lets say 50mm at f2.8:
Subject distance 10 ft
Depth of field
Near limit 9.39 ft
Far limit 10.7 ft
Total 1.29 ft
If this were to happen again, I'd try to back up, crank up the shutter speed and I might go w/ manual focus if not AF-C. It's a tough call though once that "event" starts happening... do I move further away to improve my chance of getting a decent shot but risk having the event be over, or instead, do I take a hail mary shot hoping things work out but knowing that they probably won't.
Thing is, w/ sports like tennis, car racing, or motorcycle racing, the k10d does great. Distance and predictability makes these activities easy... but a hyper 2 year old w/ low, uneven tungsten light in close quarters? that's a tough shot. I'd almost think that using my 12-24 would be best since at say f4 @ 14mm everything between 3 and 12 feet would be in focus so I could just shut off AF....
Sorry for the rambling, but I'm trying to work through this scenario too...