[vanyagor]

The essence of the bug:
When the mode dial is rotated to or through the GREEN mode or the USER mode, the AF Fine Adjustment resets to zero and stays zero until you reboot the camera or press the menu button.

Details:
My testing showed that if the mode dial is being rotated from any mode other than GREEN, USER or Video into the Green mode or USER mode and then back, the AF Fine Adjustment value is being reset to zero and stays there (which can be confirmed from the EXIF or actual focus in the image). However in the Green mode itself (and the USER mode) the AF Fine Adjustment value is always the original one (the one you set). Note I did not do precise tests with focus charts to confirm for sure if the focus actually shifts. My unprecise tests seem to confirm that as well as the reports from the user who has pointed out the bug to me (I do not know how precise his testing was).

Going into Menu or turning the camera off and on returns the AF Fine Adjustment setting to the value you have set it to.

My equipment:
Pentax K-5 FW1.14 + Tamron 17-50 f2.8 AF Fine Adjustment set to -10. Pentax DA 40mm f2.8 Limited (tested both with +10 and -10)

History:
The bug was pointed out to me by Kerusker on another forum. He thought the reset happened after shooting a short video or using the USER mode. However my testing seems to confirm that it is actually rotating the mode dial through or even to-and-back the Green mode or the USER mode is doing the reset. Kerusker mentined that he noticed the behavior in 2011 with K-5 FW1.10 +DA 55-300mm. He has reported the bug to Pentax Germany and according to him Pentax Germany has acknowledged the error. Subsequent FW updates did affect the exact behavior, though never fixed it according to Kerusker.


The impact of the bug:
The bug may be quite serious if you rotate the mode dial through the GREEN or USER modes when you operate the camera. Especially if your AF Fine Adjustment values are extreme. The bug completely defeats the purpose of AF Fine Adjustment feature in this case.

Work-around:
Pressing the Menu button after returning the mode dial from USER or GREEN mode. Turning the camera off and then on.

Update: the issue is still there with firmware v.1.15 on K-5

---

Last edited by vanyagor; 09-15-2013 at 02:17 AM. Reason: updated for newest firmware v1.15

[JimmyDranox]

Very interesting (sadly). I also want to make some AF adjusments on my K-5. I hope I find time to make it in the coming days, and will communicate the result.

[Adam]

Could be because it's a third party lens- have you tested this with a DA lens?

[vanyagor]

Could be because it's a third party lens- have you tested this with a DA lens?

The person who pointed this bug out to me used DA 55-300mm lens, so I do not think it depends on the lens. I will retest with 40 Limited tonight.

[vanyagor]

Could be because it's a third party lens- have you tested this with a DA lens?

Just completed extensive testing with Pentax DA 40mm f2.8 Limited. I confirm same behavior as with my Tamron lens. Some more details have been determined - see the top post.

[Kerusker]

The essence of the bug:
When the mode dial is rotated to or through the GREEN mode or the USER mode, the AF Fine Adjustment resets to zero and stays zero until you reboot the camera or press the menu button.

Details:
My testing showed that if the mode dial is being rotated from any mode other than GREEN, USER or Video into the Green mode or USER mode and then back, the AF Fine Adjustment value is being reset to zero and stays there (which can be confirmed from the EXIF or actual focus in the image). However in the Green mode itself (and the USER mode) the AF Fine Adjustment value is always the original one (the one you set). Note I did not do precise tests with focus charts to confirm for sure if the focus actually shifts. My unprecise tests seem to confirm that as well as the reports from the user who has pointed out the bug to me (I do not know how precise his testing was).

Going into Menu or turning the camera off and on returns the AF Fine Adjustment setting to the value you have set it to.

My equipment:
Pentax K-5 FW1.14 + Tamron 17-50 f2.8 AF Fine Adjustment set to -10. Pentax DA 40mm f2.8 Limited (tested both with +10 and -10)

History:
The bug was pointed out to me by Kerusker on another forum. He thought the reset happened after shooting a short video or using the USER mode. However my testing seems to confirm that it is actually rotating the mode dial through or even to-and-back the Green mode or the USER mode is doing the reset. Kerusker mentined that he noticed the behavior in 2011 with K-5 FW1.10 +DA 55-300mm. He has reported the bug to Pentax Germany and according to him Pentax Germany has acknowledged the error. Subsequent FW updates did affect the exact behavior, though never fixed it according to Kerusker.


The impact of the bug:
The bug may be quite serious if you rotate the mode dial through the GREEN or USER modes when you operate the camera. Especially if your AF Fine Adjustment values are extreme. The bug completely defeats the purpose of AF Fine Adjustment feature in this case.

Work-around:
Pressing the Menu button after returning the mode dial from USER or GREEN mode. Turning the camera off and then on.

vanyagor,
when I posted this behavior in 2011 in the other forum, there wasn't much interest in it. It seems, over here it is about the same.
Wondering about it I thought: The internet fora are irrelevant regarding my PENTAX equipment. PENTAX is responsible for it's products and so I asked PENTAX to fix this fault of my K-5.
As we know, PENTAX didn't fix it (although I think it could be easily done by a FW fix).
Before warranty expired (2 years in Europe) I asked for a fix again or for a compensation. I got the latter - but I won't talk about the details.
Nevertheless I have just upgraded to the K-5 II because of a very good offer. Konowing about the fault before buying, I will not address it again for compensation. Hopefully PENTAX will fix it soon. But as there is only a minor interest by the users, I doubt it will come soon.
Thanks for picking it up. Let's see.
Enjoy

[Class A]

Nevertheless I have just upgraded to the K-5 II because of a very good offer. Konowing about the fault before buying, I will not address it again for compensation.

So the bug lives on in the K-5 II?

That's disappointing.

It shouldn't really matter how many users get vocal about it. Pentax should just fix it. It is probably a pretty straightforward fix.

Kudos to you for tracking down the bug. It is rather insidious. You've done the hard work for Pentax and they should have the decency of fixing it.

I wonder whether Pentax Japan knows about. Given previous "Pentax communication" anecdotes, Pentax Germany knowing about the bug doesn't imply that the people in Japan who could fix it also know about it.

[vanyagor]

Kerusker, thanks for the info and big thank you for spotting the bug first place. Knowing of it helps avoiding unwanted misfocus surprises.

I have reported the bug to Pentax USA and today I have received a confirmation from them that they have forwarded it to the technical division in Japan. I will forward addittional details to them tonight and also post their response here.

[vanyagor]

Long promised (by me) the response I have received from Pentax:

"Dear Mr. XXX,

Thank you for contacting PENTAX.

Also, thank you for reporting this issue with the AF Fine Adjustment on the K-5. I have forwarded your email to our senior technical support specialists in the corporate office for further investigation.

If you are in need of further assistance, please respond to this email or call our technical support center at 800-877-0155.

Sincerely,
Randall S.
PENTAX RICOH IMAGING AMERICAS CORPORATION /
PHONE: 800.234.0276 /800.877.0155 / BE INTERESTING. PENTAX"

I am forwarding further details to them. I intend to push as much as I can on them to have it fixed.

[vanyagor]

Just tested if the issue is still there with the new firmware 1.15 for K-5. It is still there.