[bymy141]

After 1 year and 10k actuations, traveling the world, my K-7 pictures were out of focus.
I calibrated my lenses when I got the camera a year ago.
Now I needed to do that again.
On average the calibrations changed from around -6 to around +4!
Per lens the differences are +/- 2, more or less the same as before. So it is cleary the camera that changed.

Does anybody have the same experience?

- Bert

[SPA]

I suggest you first to change Firmware, then to reset all focus settings.
The last 2-3 FW has a better AF and now I don't need any focus calibration yet.

[conradj]

i've found the same thing as bymy141 in that i've been in the habit of recalibrating the fine autofocus of my most used lenses every few months, and have found that they're always different than the last time.

i just attribute it to the wearing in of moving parts and also changes in the responses of electronic sensors-- attribute the same causes for the gradual drift of the horizontal level. Like many other K-7 owners, i do wish they'd make that level user-adjustable.

i found the bigest changes to microfocus settings happened when the K-7 was new, and recently the changes have been minor, to the point where i'm not sure if it's because of changes in my physiology and my having learned the camera better over time.

Love the thing, hope it lasts forever. Use it a lot more than just abt any other camera i've owned and that's made me a better photographer.

[Groucho]

My K-7 was also misfocusing slightly by about 10k photos, as was my K20D. Both were sent in to Pentax for adjustments under warranty and were fine afterward.

You can probably fix it with the in-camera adjustments, but with the K-7's three-year warranty, it's worth sending it in; they'll also check your focus screen and anything else you ask about. (Mine was getting a single hotpixel when shooting video, for example.)

[bymy141]

You can probably fix it with the in-camera adjustments, but with the K-7's three-year warranty, it's worth sending it in;

I live in Europe, the Netherlands, Pentax acts less customer friendly here:
- 1 year limited warrenty only
- No rebates
- Higher prices

Living here has positive sides as well ;-)

- Bert

[Arpe]

Interesting, didn't realise I'd have to recalibrate. Thanks.

[r0ckstarr]

On my Pentax 18-250, it has been sharp and in focus between 18-150mm, but I have noticed that overtime anything from 150-250mm is getting worse as far as AF is concerned.

Would this be a reason to calibrate? If so, how do I calibrate the long end of the lens without changing the focus between 18-150mm?

[bymy141]

On my Pentax 18-250, it has been sharp and in focus between 18-150mm, but I have noticed that overtime anything from 150-250mm is getting worse as far as AF is concerned.

Would this be a reason to calibrate? If so, how do I calibrate the long end of the lens without changing the focus between 18-150mm?

No, it is not that the lens is more off long than wide. It has to do with the Depth of Field, which is a factor depending upon lens focal length, subject distance and aperture.
Depth of Field is shallower for longer lenses.

Let's do an example:
For a subject at 10 meters (focused at), with 18mm at f 3.5, your DOF is between 3.5m till infinity.
For the same subject at 10 meters, with 250mm at f 5.6, your DOF is only 9.83m till 10.2 meters!
So, if your AF would be off by 0.5 meters, you will probably not notice that that at 18mm, but all your pictures at 250mm will be out of focus...

See also: Online Depth of Field Calculator

So, you will need to recalibrate I guess....

- Bert

[Groucho]

I live in Europe, the Netherlands, Pentax acts less customer friendly here:
- 1 year limited warrenty only
- No rebates
- Higher prices

Living here has positive sides as well ;-)

- Bert

Fair enough; there are certainly some things I don't love about living here but relatively cheap goods is a positive. I didn't see a location in your profile so I didn't know.

Has it really been over a year since the K-7 was released? I suppose it has... but not by much. It's probably a good idea to get it tweaked when the warranty's almost up if there's any question about the focus accuracy...

I live in Europe, the Netherlands, Pentax acts less customer friendly here:
- 1 year limited warrenty only
- No rebates
- Higher prices

Living here has positive sides as well ;-)

- Bert

It seems like Pentax have 2 year warranty in Netherlands too. Reparatie aanbieden - PENTAX Europe Imaging Systems

Don't understand dutch so much.