[cali92rs]

So if I was looking for a set up where the priority was a quick AF (and a decent zoom+IQ) what would you guys recommend?

1.) Get an 18-135 and put it on my K-5 (around $400 give or take).

2.) Get something like a used D90 w/18-105 for a couple hundred more (around $600-$700 give or take)? Maybe a similar route w/ Canon? Would the AF performance be considerably better than an 18-135?

I wouldn't get the D90...it was a fine performer in its time but you can get better for cheaper. I would rather get a used D7000 if you want to use older lenses without motors or a 5200 if you don't mind using AF-S lenses.

[RonakG]

I agree. Have friend who just got a D7000 and I got to try it on our weekend trip to a park. D7000 paired with 18-105 blew my K-x + 18-135 combo out of the water (I know that's not a fair comparison). I was pleasantly surprised. I knew that Nikon's were really good at AF speed, but didn't think there was so much difference.

How does a D7000/D7100 compare with K-5 II in terms of AF speed (not accuracy)?

BTW, the D7000 is heavily discounted right now. See this deal on B&H - Nikon D7000 DSLR Camera Kit with Nikon 18-105mm DX VR Lens 25474

[Aegon]

Choosing between a K-5 and D90 based on an 18-1x5mm AF speed is like choosing between guitars based on the strings.

I'm hoping that, as a Canadian, you'll play guitar and understand the analogy.

[LFLee]

I think one need to test AF with large aperture lens, to see if fast = accurate?

[tuco]

I think one need to test AF with large aperture lens, to see if fast = accurate?

I've done that test with a Sigma 35/1.4. It is both fast and accurate on a D800. Of course that is after you have performed a AF fine-tune for each lens you use.

[akptc]

I realize this is an old thread but today I decided to dust off my D90 with 18-105 and 55-300 to shoot my kid's softball game and I was rather frustrated with the AF speed, especially on the 55-300. I recently started using K-5 with Sigma 50-500 and must say the AF on that combo is blazingly quick. I mean, I simply don't miss shots with this combo, it's that good.

[neostyles]

Pentax's autofocus has never been that great, and its a large part why i jumped ship. I was just tired of..

*model poses*
*af proceeds to hunt, even in broad day light*

Now i know that this is perhaps less of a problem on newer ones like the k30 but in my extensive research into what camera i should get, even the newer pentax cameras seemed a pretty inconsistent.. One day, i forgot my pentax and so i borrowed on of the the school's canon's. It was a t3i i think and even though it was an entry level offering, it destroyed every pentax i have ever used frankly and even the ones that ive seen in youtube demonstrations. More than the speed, whats always really bugged me about pentax af is the smoothness of it (or rather lack thereof). The t3i was like butter, where as the k20 was.. well not exactly the same. This really creates issues or video when things jerk in and out of focus.. and right at the time that i was thinking about upgrading i was also making the switch to video.