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03-17-2010, 07:53 AM   #1
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K-7 (or K20D) owners with DA35: How is AF?

Well, I thought I had a K10D with flawless AF. It works really well with my (up to recently) main lensens DA16-45 and DA70, and I've had mostly good results with DA50-200 too.

But I have very mixed results with the DA35 at distances of a few meters. Very close up it AFs very good, at portrait distance and close to infinity it's OK, although I have a few misses, but at about 2-10 meters distance, I get a lot of misses, it often tends to focus on objects that are not within where I expect the AF point to be. My DA35 doesn't seem to be a bad sample, when focus is right, it's very sharp at all distances, even at 2.8 (and at 5.6 it's out-of-this-world sharp, even at long distances).

So, is this better with the newer bodies?

(btw. this doesn't stop me from using the DA35, it's been almost glued to my K10D since I got it for Christmas, and has already brought me two PPG entries)

03-17-2010, 08:53 PM   #2
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I upgraded from a K10D to K-7 just this week actually, mostly because of AF problems, although it was a 43mm limited that put me over the edge. I could not for the life of me, debug adjustments or not, get it to focus correctly at 1.9.

I have a DA35 as well and it is a whole new lens on the K-7. I would miss focus a bit on the K10D and it would rack all the way out and in. Not only is the K-7 much faster at doing that, it rarely does a complete miss.

DA35 on the K10D was a lot of hold the af button, click click click click, click, click, click.. click ... click as it slowly zeros in on focus. Even then sometimes it wasn't correct and I would hit the AF button a few more times to see if it was its final answer. I used it like this for a year, and got my own share of PPG shots out of it.

The other good news is that quick shift is amazing in live view and movie mode. You don't have to reach down and flip the AF/MF switch when you are doing manual macro stuff, just focus and fire.
03-17-2010, 09:43 PM   #3
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I've used the same DA35 on a K10D, K20D, and K-7.
AF seemed fine on every camera. I haven't had any problems with any body.

My K10D also worked fine with the DA21, a combination that caused other people headaches.
03-17-2010, 10:32 PM   #4
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QuoteOriginally posted by gazonk Quote
Well, I thought I had a K10D with flawless AF. It works really well with my (up to recently) main lensens DA16-45 and DA70, and I've had mostly good results with DA50-200 too.

But I have very mixed results with the DA35 at distances of a few meters. Very close up it AFs very good, at portrait distance and close to infinity it's OK, although I have a few misses, but at about 2-10 meters distance, I get a lot of misses, it often tends to focus on objects that are not within where I expect the AF point to be. My DA35 doesn't seem to be a bad sample, when focus is right, it's very sharp at all distances, even at 2.8 (and at 5.6 it's out-of-this-world sharp, even at long distances).

So, is this better with the newer bodies?

(btw. this doesn't stop me from using the DA35, it's been almost glued to my K10D since I got it for Christmas, and has already brought me two PPG entries)
The issue with some lenses, and macros in particular, is that they can AF differently at differing distances. With normal lenses the AF differences are usally minimal and normally not noticeable, but with macros AF at macro focus distances can be noticeably different than at normal focus distances.

I do notice that my DA35 macro is different at macro distances when compared to "normal" subject distances.

The best idea is to calibrate the AF adjustment feature (K20D and K-7) so that the camera AF's correctly at normal subject to camera distances, but you will need to manually focus at macro distances, where you are more likely to manually focus anyway.

Zooms can also be culprits with AF being different at differing zoom settings and this is why they are difficult to adjust accurately even with the AF adjustment feature on the K20D and K-7.

03-18-2010, 02:45 AM   #5
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Thanks for all the answers!

Lance: I don't think it really consistently either back- of front-focuses at mid distances, it's more as if the focus points were too bigger than with the other lenses, so it chooses some high contrast area which shouldn't really be in the focus point (and yes, I know they are bigger than they look in the viewfinder!) - or that it either back- or front-focuses slightly on the chosen point (as if it doesn't move the lens precisely enough - the throw is insanely short at these distances, of course).

Anyway, two days ago I did an informal "brick wall test" by taking a few pictures of a building at some 30-40 meters distance, and with good high-contrast lines to focus on (windows) it nailed focus perfectly and the sharpness was excellent all over the field of view, even at f/2.8. And these were all auto-focused, and I think I hardly had any misses at all on that day.

All in all it's not a big deal, it just sometimes slightly reduces the value of this lens as a "snapshot walkaround lens", since you may need some more time to nail focus than I e.g. need with my DA70.
04-10-2010, 08:54 AM   #6
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da35 af

Hey.
I use DA35 on K20D first didnt shoot much with it, but never notice this problem.
On K7 i shoot few pics confirmed by AF but they are blurry in all range, there is no sign
of BF/FF. Shutter speed 1/1000 sec for example.
I did some AF FF/BF test on printed test charts , and it looks perfect.
04-12-2010, 06:05 AM   #7
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QuoteOriginally posted by breethagh Quote
Hey.
I use DA35 on K20D first didnt shoot much with it, but never notice this problem.
On K7 i shoot few pics confirmed by AF but they are blurry in all range, there is no sign
of BF/FF. Shutter speed 1/1000 sec for example.
Strange about the K-7. Was this at close range or close to infinity? I've had a few focus misses at close to infinity where everything looks blurred, so I was wondering if it sometimes locks focus at past infinity?
04-14-2010, 12:12 AM   #8
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It was close range about 2 meters other pic was something about 5 meters.
I used 1 central point AF.

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