[treebeard]

Okay, so I had to sell off all of my Nikon gear due to finances and I scraped enough money to get a K10D. Last year I used one with some of my SMC lenses and the 35mm macro Limited. I got the K10D used from B&H and I just got the 35mm Limited again. Problem is that the AF on my K10D seems to be completely crippled. Using the center focal point just does not work. I set the focal point to light up and turned the beep on for my tests and 90% of the time the focal point will light up and the camera will beep but when I look at the images the focus is way off. Today, I took shots of my kids climbing a rock pile at ISO 400 shooting at f/2.8-f/4 and between 1/800s-1/1250s and the results were appalling. I have posted some examples below. I have contacted Pentax about the issue. What's maddening is that when the camera does lock on correctly the image is nice and sharp! The first image was at 2.8, ISO 400 and 1/1000s, the second one is at 2.8, ISO 400 and 1/1250s and the third one was at 2.8, ISO 400 and 1/1250s. Then look at the last one, same settings as the third image but the focus is dead on and the image looks like I expect it to I have a few that are even worse. Any suggestions?

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Last edited by treebeard; 02-08-2011 at 05:34 PM.

[Rich_A]

Without knowing your specific shooting style, I would guess that you're using AF-S for your shooting? If you are in single-shot AF mode, you are very prone to AF issues if you aren't careful when you press the shutter release halfway down. You really need to make sure that you're aiming your center focus point on exactly what you want to be in focus and then engage AF. Otherwise, as it appears in the photos, you might inadvertently capture a focal point behind your subject before recomposing the image for your final shutter release.

I have been using this two-stage approach since I started using AF cameras and very rarely get AF errors that aren't my fault. I will approach it in two ways, if the subject is at a middle distance and I am at a middle aperture (smaller than f/5.6 or so), I'll use the center focus point and aim at what I want to get in crisp focus, press the shutter button down half way to achieve focus lock, recompose the scene for a proper composition and then release the shutter button completely.

The second approach is for very shallow depth of field (larger than f/4). I'll usually switch my focus point to where I will be composing the main focus point. I'll then use the same approach as described in the previous paragraph except for the recomposing bit. This prevents (as much as possible) changes to the focus plane and subsequent missed focus shots with such shallow depth of fields.

I apologize if I'm giving you advice you're already familiar with. I own the K-7 and the 35mm DA macro and haven't had any issues with missed focus using these methods.

[HGMonaro]

get these results a lot of the time (K10D)... drives me nuts!

In your 1st pic I'd have focused (centre point) on the rocks to their right a fraction and recomposed. Still no guarantee though. Same (focus on lads) on the 2nd. 3rd, aim a bit more left then recompose... getting the drift here! Lots of recomposing...

Someone's going to say that the focus point is not small enough to point it at such objects and expect it to 'recognise' it, well I could show pics where the foreground objects take up a lot more of the area and it still likes to lock on the trees in the distance!!

[treebeard]

The focus point on the first picture was on my son's arm, the focus point on the second one was on my closest son's right shoulder. I see no excuse for the AF not working properly on the first two, especially since there is absolutely minimal movement. I have shot with D700's, D300's, MkIII's and MkII's and I have never had focus issues like this. The camera is not properly working and it's either going back or Pentax can fix it.

[kenyee]

One slightly annoying thing about Pentax's focus points is that they're a *lot* bigger than they actually are, which is quite unlike Canikon. Draw an X on a piece of paper and turn on each focus point and hit the X from top/bottom/left/right to see when it claims it's in focus.

[treebeard]

One slightly annoying thing about Pentax's focus points is that they're a *lot* bigger than they actually are, which is quite unlike Canikon. Draw an X on a piece of paper and turn on each focus point and hit the X from top/bottom/left/right to see when it claims it's in focus.

Interesting test....I will try it. PRofMA...I like that.

[Avenger]

I have a K10d as well and had focus issues which I thought was a lens issue, then I read this https://www.pentaxforums.com/forums/pentax-beginners-corner-q/69113-back-focu...e-vs-body.html

My 16-45 has front focus issues but my 50 is bang on and the AF actually focuses better than I can on a focus test chart. I have not done any adjustments to the focus calibration. Now I focus manually with better results. You can find the lens chart here Home

What focal length are you using because I find the zooms have issues as opposed to primes. Maybe the camera was already adjusted by the previous owner, which firmware are you running since the focus calibration was removed in 1.30

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Last edited by Avenger; 09-16-2009 at 07:09 AM.

[treebeard]

I am using the 35mm Limited Macro. I was using an SMC 50 1.4 a few days ago and I have to admit that I did pretty good getting the majority of my shots (the one's where my kids were actually moving). I have the latest firmware. Below is an example of how well I did with my SMC. Shot at ISO 200, F/4, 1/1000s. By the way, I never use the auto AF feature of the camera.....I am strictly a center point AF guy.

Any chance I can go back to 1.20?

[Avenger]

I'll have to find the thread which talks about going back with firmware, as I recall it is hit and miss, some people were OK others not. The other thing I noticed is that your shooting with a open aperture, what about trying f6-11 and a slower shutter speed. Even at 250/sec should be fast enough to stop motion. Did you try the anti-shake, I tried it for the first time and was surprised at the sharpness it seemed to add. The other thing I found out is that the AF uses pixel contrast for focus so the camera can't focus on a blank sheet of paper for example, or say a dark shirt that covers the AF area. These are some of the things I've come across, researching the focus problem actually lead me to PentaxForums. Hopefully you have a better experience with your Pentax gear!

[treebeard]

I took some shots at 5.6 and 6.3 between 1/250 and 1/500 and it appears as if I have the same issue but I really need to do more testing.

[treebeard]

I have come to the conclusion that my K10D just can't focus on anything that moves unless I get really lucky. I spent about an hour in my backyard today with my 35mm Limited lens, using center focus point and below are two hideous examples of what the AF does. I am sending it back to Pentax as these results are unacceptable.

1st one is ISO 400 @ f/4, 1/800s
2nd one is ISO 400 @ f/4 1/1600s

[builttospill]

I have come to the conclusion that my K10D just can't focus on anything that moves unless I get really lucky.

I have the exact problem with my K10D. I get tack-sharp photos on non-living subjects, but 95% of my people shots are out of focus. I had a shoot over the weekend and every single photo out-of-focus! It's frustrating. I used the FA 43, DA 40 and DA 17-70 for the shoot, so I'm not seeing a difference with primes or zooms. I use AF-S and I switch between AF-SEL and AF-Center. I guess my camera just likes trees much better than people!

The pictures aren't blurry, they're out of focus. The same as yours treebeard. Even on a tripod I'll get similar results.

I'll try the focus chart, I'm gonna see if I can go down to firmware version 1.2, but if those don't work I guess I'll send my camera in to Pentax to see if they can do something.

Has anyone had this problem with the K10D and resolved it?

[treebeard]

I downloaded Debug mode for the K10D (firmware 1.30) and did an AF adjustment of +120 with my 35 Limited Macro. It made a huge difference. I tested it by taking photos of my 2 toddlers at the playground....running, sliding, etc. It appears that 90% of my OOF shots have disappeared and when I go to use the macro feature of the lens it does not hunt like it used to. Kind of silly to have to send in a camera with a known issue and then have to pay Pentax to fix it. I will be curious to see what they tell you.

[kenyee]

Wow. Sounds like it was a BF issue (I thought those shots were locked on the background). If you send it back w/ test images, Pentax can probably fix it (they just need better proof sometimes ;-)

[treebeard]

No...those shots were locked on the front of my 2 1/2 year old's shirt. I have soooooo many examples just like those, but after making the AF adjustment my 35 Limited works just fine now.