Originally posted by ytterbium Every Pentax user i know, who has switched to canon 40/50D because of AF describe the difference as night and day. Even with the cheaper non USM/L lenses. It simply works, where others are just rated to work.
Still, all of them told me, that they would rather have stayed with Pentax unless they absolutely needed the specific AF performance (Very often low light or fast action tracking, paid work).
No matter what can be read, i suggest you trying out K-x, 40/50D and see what the speed feels like.
You should also put on paper and see the switching costs. To K-x vs whole system. Then think about the AF gain you get and features you loose.
From my experience im most confused, not when the AF is slow, but when it simply doesn't do anything. I half press the shutter button, and nothing happens - i have to repress it several times before it starts focusing. And i get no AF fail or anything.. camera meters but no AF.
Perhaps it depends where you are coming from.
The K-7 does pretty well compared with the 40D.
It is so much better than my K10D.
We did a 3 week tour through Zambia last year and we've done a lot of night and walking safari's.
A lot of wildlife and birdshooting around sunrise / sunset and in darkness with a flashlight. We were either by ourselves or with small groups (4-6).
Most other people we met were carrying Canons. So I did a lot of very low light shooting shoulder to shoulder with them.
I can tell you that a K-7 / DA*60-250mm combi is on par with Canon.
I worked a lot with a German gentleman who owned a 50D and a 28-300mm f3.5/5.6 zoom lens and my K-7 was faster and more often in focus.
Contineous AF is where the problem lies with the K-7.
Worked with Ian Murphy there as well, who shoots D3x with a 200mm f2 lens.
That is a different class completely.
- Bert
A few low light examples:
I've got lots more like that.