[user440]

Even my old *istDS had no problem at all focusing a F1 car at 200-250km/t from a distance of about 30 meters. The lens used was a FA400/5,6. In fact, most shots that day was perfectly in focus. They passed this turn so fast that I struggled with pointing the camera at them.

Nice bright sunny days are great. Ever try shooting a Rally car 30 feet from you at 8pm in the winter time? I've used a lot of different cameras, it's pretty clear when one works properly for the application and when one is not suited for the application. When I hit the shutter, I expect it to fire, not hunt - hunt - hunt - hunt - nothing.

That's ok though, some tools are suited for jobs better than others.

[CWyatt]

It might be compression/re-sizing/heat haze but I'm not sure that that motor racing shot is in focus?

Having done some motor-racing this summer using high-end Nikon gear, I would not like to do pro work requiring fast AF with anything which performed noticeably worse.

[Torphoto]

Something again not mentioned enough is not the Pentax cameras AF speed but the lenses!

Shooting with a 16-45 on the k20D it can hold it's own, a limited same thing, put the 50-135 on and suddenly things become painful. Yes the K-7's AF is alot better but even with the 50-135 it slows to a crawl. I would have no problems shooting the K7, the K20D even in most situations vs my 5D or the 7D but not with the 50-135 or any other sdm lens, it's just painful after using 70-200 L glass.

The K-7 brought the AF up to par but the lenses still need faster AF and I mean ALOT faster.

[stanleyk]

On auto focus I watched two documentaries recently, one was on William Eggleston and the other on Edward Burtynsky. Funny thing was William Eggleston would manually focus his camera take one photo then walk off. Burtynsky also didn't seem to have this auto focus thing down either. Neither does Richard Avedon. And I'm pretty sure Ansel Adams and Diane Arbus didn't either.

That said I'm sure if they had ALOT faster auto focus they would have all been or be better photograhers.

[Jonson PL]

It might be compression/re-sizing/heat haze but I'm not sure that that motor racing shot is in focus?

Having done some motor-racing this summer using high-end Nikon gear, I would not like to do pro work requiring fast AF with anything which performed noticeably worse.

Here was another thread discussing the AF of the K7, from a Pro using it together with the Eos 1D Mark III and Nikon :
https://www.pentaxforums.com/forums/905596-post95.html

[inbetween]

Even my old *istDS had no problem at all focusing a F1 car at 200-250km/t from a distance of about 30 meters. The lens used was a FA400/5,6. In fact, most shots that day was perfectly in focus. They passed this turn so fast that I struggled with pointing the camera at them.

I agree. This was my K100D 1/1500 F6.7, FA J 75-300 set at 190mm. These guys were passing us at well over 100mph! If my K-7 performs at least this good, I'll be happy.

[CWyatt]

Here was another thread discussing the AF of the K7, from a Pro using it together with the Eos 1D Mark III and Nikon :
https://www.pentaxforums.com/forums/905596-post95.html

Interesting, thanks for that. I still think for something like motoracing, a focus system which quickly tracks an object you have selected across the entire frame is pretty useful...

[CharlieO]

Even my old *istDS had no problem at all focusing a F1 car at 200-250km/t from a distance of about 30 meters. The lens used was a FA400/5,6. In fact, most shots that day was perfectly in focus. They passed this turn so fast that I struggled with pointing the camera at them.

I love this picture. It almost makes me believe I can smell burning rubber, oil and exhaust fumes. Great shot!

CharlieO

[LeDave]

Wow great shot indeed, always been fascinated by Formula One cars and the tracks they drive in, so much skill required to handle those beasts in such crazy tracks.

[StigVidar]

The F1 picture couldn't been taken with AF if *istDS didn't have predictive tracking. If the shutter lag on *istDS is 1/10 sek, this car would move 7 meters and it wouldn't be sharp at all if the camera wasn't tracking properly.

[cwood]

The boat and F1 shots are very nice but are not a good indication of AF performance in any way. I'd guess they were both taken at at least F8 making their DOF more than twice the length of the vehicle. This is why you can see that both the front and rear tires on the F1 car are in focus. If this photo had been taken with the Pentax 300mm F2.8 @ F2.8 using an *ist, it would not have be in focus because the camera had no predictive tracking capability. The K-7, on the other hand, is the first camera in the Pentax lineup to be able to pull off the shot with a high rate of success using AF (happily ignoring the fact that people have been taking shots like this with MF cameras for decades)