K20D AF Accuracy Improvement Over K10D/K100D

Hi All,

It's been a while since the last time I start a thread here at the forum. I'm still around, just not posting as often as before.

Anyways, I was one of the lucky guys who got the K20D before most of the others. Got the camera last Friday, quite happy w/ it so far. We've seen enough reviews and handson reviews here and somewhere else, but I haven't seen anyone reported the accuracy improvement of the new camera yet. Thought this might be helpful to some K20D potential owners

I've been using a K10D and K20D in the past year or so, happy w/ both, but I did find some focusing issues w/ some of my lenses, like the DA21, FA24, FA77, FA*200/2.8, and even a couple FA31. The worst of the lot is the DA21. I've tested probably not less than 10 of them on both my K100D and K10D, all of them have BF problem

Surprisingly, all these lenses don't seem to have any focusing problem anymore w/ the K20D, including the DA21 I know we can adjust AF w/ the new camera, but I haven't come to the need to do AF adjustment w/ any of my lenses yet. That's great, isn't it? I hope this would be the same to all the other K20D owners.

The DA21 is a great little lens, I really love it, but its BF problem always bugs me. It almost spoiled one of my shooting events (I forgot to adjust the AF back to normal after I mounted another lenses on the camera, most of photos by K100D were OOF :(. Luckily it's the backup body of the K10D...). I tested many copies of this lens, and all of them had the same BF problem (I wasn't too lucky w/ this lens I guess).

Here are two testing photos I took w/ K100D and DA21 quite a while ago (wide open, 100% center crop).

Before AF adjustment:

After AF adjustment (in debug mode, add 120um for AF adjustment):

They were handheld shots. I took several of each, the results came out the same. You can see the improvement after the AF adjustment. The DA21 behaves pretty much the same on my K10D.

Here are a couple testing shots I just took w/ the same DA21 lens and the new camera K20D (100% center crop, w/o any AF adjustment):

Because the higher resolution w/ the new camera, I took two shots, one as I did w/ the K100D at near the minimum focal distance, another one to get similar size to the one from K100D after cropping.

I've noticed the same improvement w/ my FA*24/2, FA77 and FA31, and the FA*200/2.8 as well. I guess this is a good news for DA21 lens lovers

The other thing I noticed is that AF.C is much more reliable w/ the K20D than w/ the K10D. I've been using AF.C setting w/ the new camera since the second day I got it, and I've been very happy w/ the results so far.

Hope this is helpful to some guys here.

Hi Frank, welcome back!

I also have the K20D and while I haven't conducted extensive tests (I traded in my K10D when I received the K20D), I was very pleased with the AF performance of the K20D this weekend at my wife's 10k road race. I shot probably 50 or more shots with the DA*50-135 in AF-C (using both center AF point and the matrix AF points) and out of all those shots, only 2 were out of focus to the point they were unusable. I shot people coming at me, running in front of me, and running away from me and the tracking was fast and accurate.

Granted, it was a sunny day with lots of light, and the 50-135 was wide open, but I was perfectly satisfied with the performance.

I tried to take some BIF shots this evening with the Bigma, but I ran out of time. I shot a bunch a few weeks back with the K10D and the Bigma, so if there's an improvement there, I'll know it's the K20D.
--
Russ
http://www.flickr.com/photos/rfortson/
http://www.pentaxphotogallery.com/russfortson
Even bad photography can be fun

Hi Frank,

Sounds encouraging! Please help us with the following test: try use your FA* 85/1.4 in tungsten light and see if the K20D exhibits front-focus in this situation. I noticed front-focus under tungsten light with lenses faster than f/2.8 almost 100% of the time from the *ist D to the K10D. If the K20D can get rid of this "habit" I'm closer to being sold.

Peter

Russ Houston wrote:

Hi Frank, welcome back!

Thanks

I also have the K20D and while I haven't conducted extensive tests (I
traded in my K10D when I received the K20D), I was very pleased with
the AF performance of the K20D this weekend at my wife's 10k road
race. I shot probably 50 or more shots with the DA*50-135 in AF-C
(using both center AF point and the matrix AF points) and out of all
those shots, only 2 were out of focus to the point they were
unusable. I shot people coming at me, running in front of me, and
running away from me and the tracking was fast and accurate.

Granted, it was a sunny day with lots of light, and the 50-135 was
wide open, but I was perfectly satisfied with the performance.

I just bought the same DA50135 lens, along w/ a DA1650 as well. Hopefully they'd be here in a week or so

I tried to take some BIF shots this evening with the Bigma, but I ran
out of time. I shot a bunch a few weeks back with the K10D and the
Bigma, so if there's an improvement there, I'll know it's the K20D.

I only got chance to use the FA24, 31, 77, 85, and a DA*200 on the new camera, all perform quite well, no AF issue so far. But the 24,31,77 and FA*200 (which I also have) all have focusing problem on my K10D Luckily the local Pentax agent helped me to adjust AF for some of my lenses on the K10D

-- hide signature --

Russ
http://www.flickr.com/photos/rfortson/
http://www.pentaxphotogallery.com/russfortson
Even bad photography can be fun
http://farm1.static.flickr.com/158/340477901_8607cf90fc_m.jpg

Cheers!
--
Frank
GMT+8hours

Pete Fang wrote:

Hi Frank,

Sounds encouraging! Please help us with the following test: try use
your FA* 85/1.4 in tungsten light and see if the K20D exhibits
front-focus in this situation. I noticed front-focus under tungsten
light with lenses faster than f/2.8 almost 100% of the time from the
*ist D to the K10D. If the K20D can get rid of this "habit" I'm
closer to being sold.

I'm sure you'd buy the new camera even the AF still got problem under tungsten It's just a matter of time

I'll do the test tonight and post the result here.

Peter

-- hide signature --

Peter Fang - Pentax user for 25 years: K10D / MZ-S / Z-1 / SFX / LX
My PBase Gallery: http://www.pbase.com/pfang

Cheers!
--
Frank
GMT+8hours

Wow, very interesting. There was a thread (started by Blende8) last year on the 'DA21 focus error' problem. Some people have the problem, and others do not. I do. My DA21 backfocusses so badly from wide-open down to f/5.6, that I've practically given up using it (NB. at f/6.3 and smaller, it is better, but still hardly stellar).

Your post indicates that your DA21 perhaps had that same back-focus problem, but that the K20D has (somehow) solved it.

Well, well, well. Maybe I might take my DA21 over to my local camera shop later today, and check this out ... many thanks for the heads-up.

Cheers,
sfa

sfa1966 wrote:

Wow, very interesting. There was a thread (started by Blende8) last
year on the 'DA21 focus error' problem. Some people have the problem,
and others do not. I do. My DA21 backfocusses so badly from wide-open
down to f/5.6, that I've practically given up using it (NB. at f/6.3
and smaller, it is better, but still hardly stellar).

Saw that thread too. Actually because some guys claimed their DA21 were spot on, I had to buy several of them to test out. But unfortunately all of them have the same "problem"

Your post indicates that your DA21 perhaps had that same back-focus
problem, but that the K20D has (somehow) solved it.

At least my DA21 is spot on now w/ the new camera

Well, well, well. Maybe I might take my DA21 over to my local camera
shop later today, and check this out ... many thanks for the heads-up.

Good luck

Cheers,
sfa

Thanks for your reply Frank,

frank wrote:
Saw that thread too.

Yes I checked it after I wrote my message, and saw that you were amongst those who had the problem ...

Actually because some guys claimed their DA21
were spot on, I had to buy several of them to test out. But
unfortunately all of them have the same "problem"

That's even more interesting. As you say, some swear that theirs was/is perfect (Godfrey springs to mind).

At least my DA21 is spot on now w/ the new camera

I wonder if you could do a favour (but not urgent). You will recall that the DA21 problem was that there were two different focus points: one (incorrect backfocus) from f/3.2 to f/5.6; and the other (much better) at f/6.3 and down. If I set my DA21 on a tripod and focus at (say) f/5.6 I get a back-focus. If I then close up the aperture to f/6.3 or smaller, the lens re-focusses.

I wonder if your DA21 mounted on K20D now keeps the same focus point both wide open and stepped right down ... could you possibly run a quick check when it suits? I will of course understand fully if that's too much trouble.

Cheers,
sfa

Frank - a few weeks ago I also tested my DA21 by pointing it at the computer screen wide open and my AF result was identical to yours (K100D and K10D). Not at all sharp. Manual focusing tightened it up noticeably. Didn't try it stopped down - less easy to tell anyway with the greater DOF.

I haven't really noticed a problem outdoors in the real world.

Can't speak for the K20D though.

sfa1966 wrote:
Thanks for your reply Frank,

frank wrote:
Saw that thread too.

Yes I checked it after I wrote my message, and saw that you were
amongst those who had the problem ...

Actually because some guys claimed their DA21
were spot on, I had to buy several of them to test out. But
unfortunately all of them have the same "problem"

That's even more interesting. As you say, some swear that theirs
was/is perfect (Godfrey springs to mind).

At least my DA21 is spot on now w/ the new camera

I wonder if you could do a favour (but not urgent). You will recall
that the DA21 problem was that there were two different focus points:
one (incorrect backfocus) from f/3.2 to f/5.6; and the other (much
better) at f/6.3 and down. If I set my DA21 on a tripod and focus at
(say) f/5.6 I get a back-focus. If I then close up the aperture to
f/6.3 or smaller, the lens re-focusses.

I wonder if your DA21 mounted on K20D now keeps the same focus point
both wide open and stepped right down ... could you possibly run a
quick check when it suits? I will of course understand fully if
that's too much trouble.

As a matter of fact, I have the k20D and DA21 w/ me right now. Did the test quite some times as you said, from 3.2 to F8, and from F8 to F3.2, there was no re focusing from F5.6 to 6.3. I even purposely turn the dial between F5.6 to F6.3 back and forth, no movement at all. Sometimes it does refocus, but it happens at other F point too, probably due to slight movement/shift between the camera and the target. I'll do the test again when I'm home tonight, w/ a tripod and see how. Will get back to you again

Cheers,
sfa

Nico13 wrote:

Hi Frank,
Thanks for the info, I am very interested in the K10 just got to talk
the other half into it as well.
She talked me into keeping the motorbike so the funds will have to
come from somewhere else now so will have to wait a little longer.
I liked the shots of the kids in the other post by the way, looking
good.

I guess you mean the K20D

Thanks and glad you like my kids photos. Hope you'd get the new camera soon.

frank wrote:
As a matter of fact, I have the k20D and DA21 w/ me right now. Did
the test quite some times as you said, from 3.2 to F8, and from F8 to
F3.2, there was no re focusing from F5.6 to 6.3. I even purposely
turn the dial between F5.6 to F6.3 back and forth, no movement at
all. Sometimes it does refocus, but it happens at other F point too,
probably due to slight movement/shift between the camera and the
target. I'll do the test again when I'm home tonight, w/ a tripod and
see how. Will get back to you again

Excellent Frank, thanks. Very encouraging so far, and I look forward to the results of your tripod testing. Many thanks again.

Cheers,
sfa

timo wrote:

Frank - a few weeks ago I also tested my DA21 by pointing it at the
computer screen wide open and my AF result was identical to yours
(K100D and K10D). Not at all sharp. Manual focusing tightened it up
noticeably. Didn't try it stopped down - less easy to tell anyway
with the greater DOF.

If you focus at the minimal focal distance (about 20cm), the DOF is quite thin even w/ the 21mm at F3.2 Slight movement will get it OOF.

I haven't really noticed a problem outdoors in the real world.

Well, to me I do see the difference even when I use the lens outdoor in the field. After some AF adjustment, it takes better sharper photos to me

Can't speak for the K20D though.

You can test the K20D camera out tomorrow at the IT Show It's from tomorrow to the weekend.

-- hide signature --

tim

Hi Frank!

Interesting comparison. Good news to me!! I also have the DA21 and I do have the same focusing problem on my K10D. I only lost one shot because of that, but still it was annoying at the time, esp since it was the best shot of a series (shooting the behind the scenes of a commercial ad shoot).

Another reason to hope K20Ds will start selling soon here in Belgium. I was told this week, but I'll believe it when I have mine in my hands...

Wim

Ishpuini wrote:

Another reason to hope K20Ds will start selling soon here in Belgium.
I was told this week, but I'll believe it when I have mine in my
hands...

Hmm, they're probably just quarreling which part of Belgium should get it first

I've seen it on display in a shop here in Norway for couple of days already, so it has definitely arrived in Europe.
--
Espen

gazonk wrote:

I've seen it on display in a shop here in Norway for couple of days
already, so it has definitely arrived in Europe.
--
Espen

In Romania it was available from 29th February.

Alex Sarbu

frank wrote:

Pete Fang wrote:

Hi Frank,

Sounds encouraging! Please help us with the following test: try use
your FA* 85/1.4 in tungsten light and see if the K20D exhibits
front-focus in this situation. I noticed front-focus under tungsten
light with lenses faster than f/2.8 almost 100% of the time from the
*ist D to the K10D. If the K20D can get rid of this "habit" I'm
closer to being sold.

I'm sure you'd buy the new camera even the AF still got problem under
tungsten It's just a matter of time

I'll do the test tonight and post the result here.

I too am very interested results under tungsten light. Thanks for testing.

Prog.