[GaryML]

What I'd do in your situation is just go out and rent a Canon setup. You can probably do it for about $150 and then you'll know exactly where they stand.

Good suggestion. That occurred to me earlier today. There are two or three stores in the area that rent equipment. The price is sort of ridiculous but it's certain cheaper than buying $3500 worth of stuff and then not liking it. I don't know if they rent the mid-range bodies but I'll call them up.

Part of the focusing problem may be the Sigma lens. It doesn't have a BF-FF issue, because focus is perfect for stationary or slow moving object. It also gives me the focus confirmation "beep" very quickly. It's just when the kids are running it won't keep up using AF-C. It does better with AF-S and that's what I usually use, but even then it gets fooled. When I used my old FA 135mm f2.8 [IF] a few times I had no focus problems-but I didn't have nearly enough magnification most of the time. I'm also going to bring my DA* 50-135mm to the next game just to get an idea of focus speed and accuracy

[Maxington]

I found that the AF-C worked much better when you left the focus points on automatic, not select or center focus. The camera seemed to pick the moving subjects far better when it could switch focus points.

I tried this the other day taking photos of my dogs chasing each other in a river, I was surprised that it nailed the focus so many times, it was even getting shots when the dogs were half-screened by tree branches and so on.

Of course, this method isn't as useful if you really need focus point on a specific spot like a face, and your DOF is narrow due to low light.

[Mr Hyde]

These came out OK. Not super sharp but then again I was using the Tamron 28-300mm on the k10D. The parrents were happy enough to buy the photos. Both photos are cropped.

[pcarfan]

I found that the AF-C worked much better when you left the focus points on automatic, not select or center focus. The camera seemed to pick the moving subjects far better when it could switch focus points.

I tried this the other day taking photos of my dogs chasing each other in a river, I was surprised that it nailed the focus so many times, it was even getting shots when the dogs were half-screened by tree branches and so on.

Of course, this method isn't as useful if you really need focus point on a specific spot like a face, and your DOF is narrow due to low light.

Were you taking single shots for each press of the shutter, or in continous shooting mode with each shot being well focussed. Does the K10D have problems in both instances for others ?

[ccallana]

Maybe its because my kid is only 5 and the little guys just don't run that fast, but pretty much every one of my 200 shots were in focus from last weekend's soccer game - his first and my first shooting a soccer game. I shoot a *istDL and a DA50-200, so nothing fancy. I was using AF-S with a release of shutter between most shots. Shot in P mode mostly, some Tv.

Granted I was right on the side line, its a small field, and it was 2pm, so very very bright.

I was shooting much wider angle shots than yours most likely as well...

I'm not trying to say there isn't a problem, just giving you my experience from this weekend.

[blwnhr]

I'm using a K10D body and the Sigma APO 100-300mm f4 EX DG lens, mounted on a monopod with SR off. Usually I use AV or TAV, and keep the aperture around f/5, shutter speed between 1/750 and 1/1250, and adjust the ISO accordingly.

I use K10D, Sigma 50-500 hand held with SR on. Tv mode @ 1/1000 or 1/750 depending on light, Auto ISO from 100-400. AF.C set to Auto point because I found the centre-point-only a bit limiting.

I am very happy with the results.

Perhaps it is because the subject isn't fully filling the frame that the AF is picking points back from the subject and focussing on them?

I have a few missed AF shots, but not enough to overly concern me.

I also shoot a LOT of motorsport and have no complaints at all, 100% in focus every time. Even with slow lenses.

[Maxington]

Were you taking single shots for each press of the shutter, or in continous shooting mode with each shot being well focussed. Does the K10D have problems in both instances for others ?

I was in single shot mode, in AF-C, not continous shot. I was firing off shots fairly often though.

[Arpe]

Maybe its because my kid is only 5 and the little guys just don't run that fast, ...

I'd say that has a lot to do with it! I've done rugby photos (of grown-ups) last winter, I often had to go back to manual focus (using Sigma 70-200 + 1.4x) once the light dimmed a little. The AF can definitely NOT keep up with an adult running at you, or across you.

I too would be very interestes in knowing the answer to the OP's question.

[GaryML]

Maybe its because my kid is only 5 and the little guys just don't run that fast, but pretty much every one of my 200 shots were in focus from last weekend's soccer game - his first and my first shooting a soccer game. I shoot a *istDL and a DA50-200, so nothing fancy. I was using AF-S with a release of shutter between most shots. Shot in P mode mostly, some Tv.

Granted I was right on the side line, its a small field, and it was 2pm, so very very bright.

I was shooting much wider angle shots than yours most likely as well...

I'm not trying to say there isn't a problem, just giving you my experience from this weekend.

I am beginning to think that it may be the Sigma lens. I will explore this further at the next game.

My son's team is 9 and 10 year olds, and the field is much larger than the 5 year olds on the "micro-soccer" fields as they call them here.

Here's an example of the issue. This was shot 2 weeks ago with the Sigma lens at 180mm, 1/500 sec at f/5.6, ISO 100 (no tele-converter), with the AF set to AF-C and allowing the camera to select the AF point. I'm trying to get the kids in the center in focus: that's my son in the blue jersey kicking the ball through the legs of the kid in the silver jersey. Notice that the kid on the left is in perfect focus, but the ones in the center (and on the center red AF square as selected) are not in sharp focus because they are moving towards the camera. The exact focus plane can be seen more clearly in the full size image. I think this shot isn't bad, but I would really like it razor sharp. (There is a bit of motion blur due to the slower shutter speed, so that is partly to blame as well.)

[sample deleted]

[Mr Hyde]

Why not trying bumping the ISO up to 400 and narrowing the f-stop to f/11 to increase DOF?

[GaryML]

Here's a shot that is well-focused. The kids were moving across from my right to my left instead of towards or away from me. Also slightly faster shutter speed (1/640 sec., lens at 260mm, f/5.6, Av, ISO 100, AF-S with auto-select, continuous shooting). It may not come out in the downsized image, but this shot is razor sharp.

[sample deleted]

[GaryML]

I'd say that has a lot to do with it! I've done rugby photos (of grown-ups) last winter, I often had to go back to manual focus (using Sigma 70-200 + 1.4x) once the light dimmed a little. The AF can definitely NOT keep up with an adult running at you, or across you.

I too would be very interestes in knowing the answer to the OP's question.

I've experimented with the Sigma APO 1.4X EX DG converter. It really hurts the AF speed. I played with it a bit last week but you are pretty much limited to manual focus with the converter.

[davemdsn]

Well, if you believe the marketing campaign, the sports pros use Canon Digital Rebels to shoot the big games. Heck, TV commercials are enough for me, lets all get Rebels.

[pcarfan]

I would think letting the camera select focus point could indeed result in picking any of the three players on the first shot,...would'nt center focus be the only one that has a chance of being consistant ?

[RiceHigh]

I have both systems and what can I say about the AF performance of the Canon is far superior, no matter for stationary or fast moving objects, no matter for low light or bright light, no matter for daylight or tungsten light (under which Pentaxes must Front Focusing, even for stationary objects).

As for your mentioned type of action photography which tracking of a fast moving objects is a must (in fact the application is quite demanding for the AF system's responsiveness), I do think that the Canon system is a no-brainer.

Just see over 90% of the photo journalists and those sport photographers at the field are using Canon, then you can know why. Nikon is after Canon quite a bit and then Pentax is far behind, as long as the AF department is concerned, frankly speaking.

For my Canon setup, I only have a 24-105L and 50/1.8II (with a 5D) so far. So, I cannot tell you about my experience at the tele side, which should be your case. What I am sure is that at tele side the AF time will be lengthened, for any system. Do note that my experiences with my $75 50/1.8II with just a conventional micro-motor is surprisingly good, the AF are hit on for most of the time, even for randomly moving objects like energetic children running around at high speeds, both outdoor or indoor.

The problem/symptom with all Pentax DSLR bodies and system is that they are less sensitive in determining the focus, it needs more time to think and then the inability of AF motor to drive the lens as directed is quite obvious and finally followed by some repeated huntings, very indecisively, until it tries to achieve the AF (after a certain timeout period) and lit on the AF confirmation signal and sound the PCV tone. And then, you will get the results! (that you have mentioned, that is, a low hit rate) :-)

MZ film cameras are better, more decisive and faster responsiveness. But then those were the days. The best thing is still the MZ-S, which when compared to the *ist D, DS, DL, K100D and K10D which is just night and day, again. Yet, the Canon 5D setup is still obviously better than my MZ-S. So, you could see the differences.

I think if money is not a major concern of you, just get a 40D with a long lens, then your problem can be resolved. (Or, to keep waiting to see if a better Pentax DSLR body will come - but which might be a loooooong wait)

After you have started a new system, you can then decide to migrate or to keep a twin setups. If you have some of the older Pentax glass which are excellent IMO, it maybe worth to keep them and wait for the next Pentax body, hopefully which can really perform. Note: Canon glass can be as good as traditional Pentax glass, but they are double or even triple in prices! Still, I found that the coatings of Canon glass are not as good ( even just compared to a typical very ordinary SMC lens, say, the $60 DA 18-55 kit lens), even for L ones. Believe it or not! :-)) )