Possible live view metering bug with K-1 fw 1.42

[BobORama]

Hi,

When in Live View the camera will adjust the aperture to get sufficient light to provide the live view image. The camera will periodically adjust the aperture in response to changing subject or lighting condition.

With FW 1.42, I am noticing the camera will rapidly cycle between two apertures about once every half second. Typically on high contrast or fine patterns. It seems as if the camera stops down the lens, undershoots exposure and rapidly switches back to a wider aperture, and does this once or twice a second. I have opened a ticket with Pentax as this did not happen previously.

https://bob-o-rama.smugmug.com/Outbound/Misc/i-LDm285Q

https://bob-o-rama.smugmug.com/Outbound/Misc/i-HD84RRs

I have seen this on grassy subjects with specular highlights. It also seems potentially related to the shift in DoF, where the subject is sharper stopped down and so the metering produces different results.

However you can see that this is pretty annoying.

Also I do not see this problem in Video live view, only when shooting stills. It also occurs when the camera is in Manual or other AE program modes with A-series or better lenses.

-- Bob
http://bob-o-rama.smugmug.com -- Photos
http://www.vimeo.com/boborama/videos -- Videos
http://blog.trafficshaper.com -- Blog

 

[KPM2]

Hello BobORama

Thank you very much for making a video about this bug !

Up to now I could not get this bug in LV with the vers. 1.42, but that means nothing.

My question is:

- do you use a prevent the highlights setting?

I ask because I see in your video the camera alternating all setting (aperture, shutter speed and ISO) meanwhile the overexpose indication get at the same time on and off, depending on the current setting.

again, thanks for posting your finding via the use of a video !

best regards KPM2

 

[BobORama]

Hmmm... I have not tried turning that off. I am pretty sure I exhausted various avenues of futzing around. But sure, I will try.

I think the highlight indication going on / off is a symptom. The camera thinks the scene is too hot, stops down, then its under exposed and it opens up the aperture to get more light - and cycles between the two.

I did get a response from Pentax that they had forwarded the videos and the issue to Japan for review. So hope springs eternal.

-- Bob
http://bob-o-rama.smugmug.com -- Photos
http://www.vimeo.com/boborama/videos -- Videos
http://blog.trafficshaper.com -- Blog

 

[KPM2]

Hmmm... I have not tried turning that off. I am pretty sure I exhausted various avenues of futzing around. But sure, I will try.

I think the highlight indication going on / off is a symptom. The camera thinks the scene is too hot, stops down, then its under exposed and it opens up the aperture to get more light - and cycles between the two.

I did get a response from Pentax that they had forwarded the videos and the issue to Japan for review. So hope springs eternal.

-- Bob
http://bob-o-rama.smugmug.com -- Photos
http://www.vimeo.com/boborama/videos -- Videos
http://blog.trafficshaper.com -- Blog

Hello BobORama

Do the new fw 1.43 solve this problem?

If so, thank you for your effort !

best regards KPM2

 

[BobORama]

Hello BobORama

Do the new fw 1.43 solve this problem?

If so, thank you for your effort !

best regards KPM2

Yes, the 1.43 firmware seems to have resolved the issue. It seems as if the camera will tolerate a 2 or 3 stop difference in exposure before it switches the aperture. I have not been able to reproduce the problem. The issue was very much scene dependent, so not 100% sure without a time machine. But so far so good!

-- Bob
http://bob-o-rama.smugmug.com -- Photos
http://www.vimeo.com/boborama/videos -- Videos
http://blog.trafficshaper.com -- Blog