[orly_andico]

Justin Serpico over on the photo.net forum gave me a very good piece of advice for improving Pentax AF performance (I have a K20D).

Shift it to AF-C. Then use the back AF button to AF. In AF-C mode, the shutter release has priority, so if things look in-focus enough, you can take the shot and the shutter won't be blocked.

I got a Canon 40D (yes, it's two generations behind the state-of-the-art, but I'm cheap) and yes, it does focus much faster with ultrasonic lenses. But the speed is because it doesn't block the shutter after the initial focus. Pentax does an initial focus, then does the famous "confirmation stutter" to refine the focus. This takes a long time.

So Canon focuses faster, yes. Is it more accurate? I don't know. Haven't tested it long enough.

That said, I tried a K-x and with my lens (D-FA 100mm) it did not feel any faster than my K20D, so I'm willing to bet that the K-x at least still doesn't match a 40D-class body.

Again, speed is one thing, accuracy is another, and I haven't tested AF accuracy on the Canon yet. It is much less likely to lose focus and rack all the way in and out than my K20D, though.

[apisto]

Cute, how old are you?

You are calling this poster childish because he wants equipment that will meet his needs? Different photographers have different needs based upon the type of shooting they do. If one's current gear is not meeting those needs, it makes sense to see if other gear will.

[jsherman999]

Justin Serpico over on the photo.net forum gave me a very good piece of advice for improving Pentax AF performance (I have a K20D).

Shift it to AF-C. Then use the back AF button to AF. In AF-C mode, the shutter release has priority, so if things look in-focus enough, you can take the shot and the shutter won't be blocked.

I got a Canon 40D (yes, it's two generations behind the state-of-the-art, but I'm cheap) and yes, it does focus much faster with ultrasonic lenses. But the speed is because it doesn't block the shutter after the initial focus. Pentax does an initial focus, then does the famous "confirmation stutter" to refine the focus. This takes a long time.

So Canon focuses faster, yes. Is it more accurate? I don't know. Haven't tested it long enough.

That said, I tried a K-x and with my lens (D-FA 100mm) it did not feel any faster than my K20D, so I'm willing to bet that the K-x at least still doesn't match a 40D-class body.

Again, speed is one thing, accuracy is another, and I haven't tested AF accuracy on the Canon yet. It is much less likely to lose focus and rack all the way in and out than my K20D, though.

I did quite a lot of shooting with two 40Ds and a 50D ust to test this exact thing, and found that while the 40/50D locked very quickly, it was often slightly inaccurate, and in an inconsistent way (both BF and FF, multiple lenses, but tested mostly with two 50 1.8s. Center-point af-s equiv, focus priority.)

I feel I trust my K20D in low-light more than those Canons because of this. (I have not shot much with the 7D or 5d* series.)

The D80, D90, and D700 were all both quick and accurate, even down to very low light levels, and in dim tungsten. Especially the D700.

I shot with a D7000 for about a day recently, and that seemed to do very well also, but not really better than my D90, and worse than the D700.


.

[orly_andico]

i'm not surprised the D700 does well. many folks rate it higher than the 1D Mk IV. and the price reflects that.

personally my old-new 40D is more usable in low light because my K20D won't even focus. but again, in low light whether AF or MF, you have no idea how accurate the focus is.. another thing, a true ring ultrasonic lens (i only have one... the 100mm macro) can do very fine AF adjustments almost instantaneously, and doesn't overshoot. again, that may be due to an overly-optimistic "in focus" algorithm on the body's part.

what i can say about the 40D is that it reaches focus really fast and doesn't hesitate. but then you're never too sure if it's in focus or not (can't tell on the matte screen). i'm replacing the screen with a split-image (just like my K20D). so maybe I'll get driven crazy by the AF soon. hopefully not..

[hegedus]

I used to own Canon 40D, then I switched to Pentax K10D. I used Canon 85mm f1.8 a lot, and I never missed focus with that combo. 40D was just perfect for me, in all aspects, specially with 85mm f1.8. Then I switched to Pentax, I expected the same performance, but was disappointed with the performance. Still, after some time I got used to Pentax, and learned it's behavior in certain conditions. Today I can say that 40D has better AF overall, but I expect to get closer to its speed when I upgrade to K7 or even better to K5.

[Douglas_of_Sweden]

Amazing how long lived some threads can be.
I have two questions with regard to the original post.

1) What does all this stuff about animals and kids mean? Maybe it is because Enlgish is not my mother tongue, but it doesn't make sense to me.

2) I'm curious. Did the OP switch to Canon, or did he/she get a K-5 or K-r, because he/she considered it anough of an AF upgrade.


The only thing I can say about it is that K-5 autofocus much faster than my K-7 which focus faster than my K20D, which focus with about the same speed as my *istDS which focus about as fast as my MZ-5. Admitevely the K20D appears more acurate than the *istDS. So to me it appears that Pentax didn't really try to compete with AF speed before the K-7/K-x, and with the K-5/K-r they have taken large steps forward. Maybe the change came with Hoya. For Pentax, as strange as it may sound, cameras have to some degree been an accessory to their lenses. Hoya maybe had them change their prioriteis. I'm just guessing, but the timing seams more than a coinsidence. If I am to guess further, Hoya will let them launch some longer glass once they have more or less caught up with AF speed. Make no misstake, I am only guessing. But I say, beware Canikon of the next Pentax generation...

[orly_andico]

I wish someone would do some real quantitative AF tests of the K-5 compared to the Big Two.

There are a lot of us who are long-time Pentax users but have grown leery of all the claims of Pentax AF speed. A K-5 is a big chunk of change to plunk down on faith that the AF performance is up to par with the Big Two, while a 50D or 60D or D300 is a known quantity AF-wise.. there are bazillions of people using these cameras.

[deadwolfbones]

Amazing how long lived some threads can be.
I have two questions with regard to the original post.

1) What does all this stuff about animals and kids mean? Maybe it is because Enlgish is not my mother tongue, but it doesn't make sense to me.

It's a lot of idiomatic/metaphorical talk.

Basically he's saying because he has kids he'll choose the best horse (manufacturer) for the course (his "course" being one that demands faster AF locking).

[Douglas_of_Sweden]

It's a lot of idiomatic/metaphorical talk.

Basically he's saying because he has kids he'll choose the best horse (manufacturer) for the course (his "course" being one that demands faster AF locking).

OK, se he is afraid that either the kids, or the horses, or the sheeps will be faster than his AF?
At least when the kids turn teenagers, the AF will have no problem capturing them before noon.

[Douglas_of_Sweden]

Some hard numbers. The journal FOTO, the oldest photographic magazine in Sweden, tested the K-r in their 2011 January issue. Here is the autofocus speed compared to what they consider similar Canikon models (with similar lenses, all 18-55 kit zooms):

Penta K-r at 18, 35 and 55mm: 0.30s, 0.35s, 0.39s (shutter-delay 0.08s)
Canon 500D at 18, 35 and 55mm: 0.28s, 0.31s, 0.31s (shutter-delay 0.13s)
Nikon D3100 at 18, 35 and 55mm: 0.31s, 0.45s, 0.47s (shutter-delay 0.13s)

The Pentax and the Canon is so close that taking the shutter-delay into account, the K-r is the faster camera at 18 and 35mm. Nikon is clearly behind both Canon and Pentax. This is a journal I trust to be unbiased and to take tests seriously (even to the degree that I'd think this is average values, not single measurements). Pentax K-5 will be tested in the next issue, against comparable models.

[Tom S.]

OK, se he is afraid that either the kids, or the horses, or the sheeps will be faster than his AF?
At least when the kids turn teenagers, the AF will have no problem capturing them before noon.

Perhaps, but if you ask them to take out the trash, there's no camera made that's fast enough to catch them before they disappear.

[builttospill]

OK, se he is afraid that either the kids, or the horses, or the sheeps will be faster than his AF?

The kids will move fast; the horse (camera) rhymes with course (the route used to get to the destination); and he doesn't want to be a sheep (blind follower) purchasing a big brand camera. That's some dilemma. I can see how it would be difficult to understand regional/cultural examples if the language isn't native.

At least when the kids turn teenagers, the AF will have no problem capturing them before noon.

I like this.

[builttospill]

...Pentax K-5 will be tested in the next issue, against comparable models.

I'd like to read the results when available. Thanks.

[antman]

I had a play with a friends new kr, and I must say it seemed faster than my K20, anyone own both?

[orly_andico]

I certainly hope to see those K-5 results. K-r results don't interest me (I know that the Canon Rebel cameras are a step below 40D/50D/60D performance, as they have the 30D AF module).