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Old Nov 4, 2010, 11:21 AM   #1
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Default Any feedback on the K5 autofocus speed

Just looking if anyone has heard if the new Auto-focus system of the K5 is a huge difference, or just a minor upgrade? Is it better in sports/wildlife action shots, or still falls abut short compared to others camera systems?
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Old Nov 4, 2010, 1:15 PM   #2
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From what I'm reading on other forums, it seems there's improved performance with it's interaction with SDM lenses. I'm not a pentax shooter, but from the little I've seen from pentax action shooters, a big complaint has been that sdm focus performance seems worse than screw-drive. From what I'm reading, the K5 handles it's interaction with SDM better. I'm still waiting on reports from sports / action wildlife shooters to see how focus tracking is compared to other pentax cameras.

You're always going to have difficulty with getting an answer as to how it compares to the competition - especially if you consider the competition to be the Canon 7d and Nikon d300s - finding experienced action photographers that have used both is going to be difficult.
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Old Nov 4, 2010, 4:32 PM   #3
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general impression seems to be its much more positive - much less hunting and works well even in very dim light conditions - as johng said seems to be better with sdm too in most cases but heard afew that lens is the limiting factor noteably the the DA* 50-135mm f2.8 - then again have heard afew say even its better too

but for predictive 3d tracking i doubt its been improved - never even been mentioned and previous generations of pentax cameras dont have it - certainly if your using the camera in low light think you will see a large improvement

same for liveview constrast detection autofocus - not upto sony's implimentation that uses the phase detection system even in live view but better than most and as good as p&s and m4/3's cameras apparently

but tracking yeah i think the d300s or 7d will serve you better

opinion here is based solely off what others have said though but have looked into the camera as much as you can without buying one in the end have descided i want a paraglider more so new camera can wait until next year maybe by then the k-3 will be competing with the big guns with autofocus too
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Old Nov 4, 2010, 5:55 PM   #4
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Originally Posted by Bowenp View Post
Just looking if anyone has heard if the new Auto-focus system of the K5 is a huge difference, or just a minor upgrade? Is it better in sports/wildlife action shots, or still falls abut short compared to others camera systems?
Hi Bowenp,

I had a long answer typed up, but it just got wiped out by a momentary power out, so I'll make an attempt to recreate it, but in fewer words.

The reports I'm reading say significant, but not huge over the K-7, very significant over the K20, and what might be considered huge over models previous to that. The biggest difference that seems to be noted in a majority of the early adopters who have previous Pentax experience is that there are few or none of the micro-corrections that most Pentaxians have found frustrating -- in other words, focus locks on the first try in good light and micro-corrects considerably less in very dim light.

I recall seeing a comparison of the PopPhoto.com AF speed tests between the K-7 and D300, but can only find the chart for the K-7 now. IIRC, down to about +5Ev, there were only a few miiliseconds difference, but the gap widened quickly between there and +3Ev and lower. The 7D was quite a bit faster across the board, but with reported improved low light performance with the larger AF sensor lenses, the K-5 should probably be pretty competitive with the D300 across the board, and that's not too shabby. A few photographers with extensive experience with the D200 have stated definitely that the K-5 is faster than that admittedly obsolete Nikon model.

I'll venture to guess that the D300 will track moving subjects better, but the K-7 does this better than any previous pentax model, and I'd suggest that the K-5 will be better. The early adopter tests that I've seen have unfortunately been pretty lame, and from shooters with little experience with this type of photography, so there's ample excuse, but nothing I've seen is conclusive, or even close. I'm pretty familiar with a lot of the members of other fora, and there are only a few who I'd trust to pull off a realistic test of AF-C tracking, and none of them have a K-5 yet. . .

I'm not very practiced at BIF, even though birds are my main concentration. I tested my K-7 against my K20 and K10, all with the same lens and witin a half hour with pretty consistent lighting. I shot jpeg, high contiuous, multipoint focusing, Av priority, ISO 400, AF-C. The lens was a Pentax 80-320 f4-5.6 at 320mm at f8. I was shooting gulls, and chose those who were flying towards me as opposed to those who were flying in a parallel plane.

With the K10, I got a max of 9 frames, with 4-5 being average, and 40-50% in what I consider acceptable focus. With the K-20, The percentage went up slightly to 50-60% and the average string was more like 7-9, and with the K-7, it raised dramatically to 75-95%, and I could usually get 15-18 frames. Number of frames is partly due to higher frame rates in the newer bodies. It must be mentioned that the shorter VF blackout times with the K-7 also improved framing and ease of tracking the birds in the VF, and I think added to the AF accuracy since I was able to keep the birds more centered in the frame.

Here's a post from my early experience with the K-7 and gulls:


A problem with AF speed tests is that they can compare bodies, but lens AF performance is a big part of the equation. A lens with a long focus throw is going to focus slower than one optimized for AF speed, regardless of body. Pentax-branded lenses seem to have been designed with MF capability as a priority, and overall AF performance will probably suffer a bit from this. For those who require faster AF, the newer Sigmas have offered HSM which is consistently touted as faster than either of Pentax's focus drive systems. Sigma also tends to optimize its lens designs for AF with much shorter focus ring throws.

Bottom line, -- I think . . . I'm expecting the K-5 to improve on the K-7. The added focus or speed options to AF-S and AF-C should allow me to develop new techniques to further speed things up if I care to. Static AF-S should be improved across the board, but especially at the low light end. Suitability for action and sports will remain nebulous as lens choice, skill level, relative size of the subject in the VF, DOF desired, and lighting conditions will all have marked effects on the AF performance.

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Old Nov 4, 2010, 9:01 PM   #5
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very helpful thanks folks
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