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Mirror Flop Investigation & Results

Jim Radcliffe

July 15, 2011

Like many K5 owners I have recently begun to experience the "Runaway Mirror Flops" with my K5. At first I thought this was a heat related problem as it just recently began while I was using the K5 in 90 to 102 degree outside temperatures.

After reading a number of posts in online Pentax forums which suggested it might be a battery related issue I decided to run a test on my K5 and was able to "force" the mirror flops to occur.

Here is how and why I came to the conclusion
that this is a battery or voltage related issue.

I have three genuine Pentax batteries. One of them was left half discharged and the other two were fully charged overnight in preparation for testing this morning.

The outside temperature during this test was 85 degrees this morning at 7:30AM.

I began shooting with the battery that was half discharged. I shot over 25 frames using that battery without a single mirror flop. I had the DA* 50-135mm mounted as this was the same lens I had mounted when the issues began several weeks ago.

I then removed the battery and placed one of the fully charged batteries in the camera and shot 3 frames before the camera's mirror began to flop. It flopped when I did a half press of the shutter and it also flopped when I pressed the AF button on the back of the camera. I then removed the fully charged battery and put the half charged battery back in the camera and continued to shoot without a single mirror flop.

I then removed that battery and placed my second fully charged battery in the camera and began to shoot again.. four shots into this process the mirror flops began again. I took that battery out and replaced it with the half charged battery and began shooting again...20 frames and not a single mirror flop.

I then decided to switch the lens to see if that might have had some connection to the mirror flops. I mounted the 43 Ltd and continued to shoot with the half discharged battery... no mirror flops.

I then removed the half discharged battery and replaced it with one of the two fully charged batteries and almost immediately the mirror flops began with the 43 Ltd. mounted on the camera. I pulled that battery and put the half discharged battery back in the camera.. 10 frames and no mirror flops. I then put the second fully charged battery in the camera, shot two frames and the mirror flops began again.

To me this seems to suggest that the issue is related to either the voltage output of the fully charged batteries or a voltage regulating component in the K5 itself.

The serial numbers of the batteries which caused the flops are: 201101 and 201012. The half discharged battery serial number is: 201011.

The two extra batteries I purchased (201011 and 201012) both came from B&H. My gut tells me that if I fully charged the half discharged battery that it would also cause the camera to mirror flop. I will charge it fully tonight and see if that occurs.

The more confusing issue is that the mirror flops did not begin until 5 months after I purchased the K5. This leads me to believe that some component in the camera is beginning to fail in some way and makes itself known ONLY when a fully charged battery is being used. This is in line with others saying that the camera finally "settles down" and operates properly. It seems that once the battery discharges a bit after a full charge the issue goes away.

Note that the mirror flops have never occurred until the last month of use and I have been using the camera a lot since I purchased it in March of 2011.

I can only conclude that the test I ran this morning with half discharged and fully charged batteries is a clear indication that there is an issue with voltage regulation within the camera itself and that this is the cause of the mirror flops. At no time does the camera ever actually take a picture during the mirror flops.

It feels good to finally be able to force the issue to show itself. Now that the problem can be replicated on demand in cameras that suffer from this issue there should be no reason the root cause of the problem can not be determined and a fix found.

What remains now is to see if Pentax will address the issue openly and find a satisfactory fix for the problem.

I fully intend to keep my K5. It is a wonderful camera and I have invested in seven lenses for it. I feel confident that Pentax/Ricoh will find a way to handle this issue. However, I will NOT send my K5 in for repair until Pentax has an official statement regarding this issue or the camera simply dies... whichever comes first.

I'm not willing to be without my camera for weeks or months until there is a sure fix for this issue.

August 29, 2011 - My K5 Returned from C.R.I.S. today
The UPS guy arrived around 6:30PM this evening with my K5 back from repair in Arizona. I have not opened the box yet due to my current workload at the office. I will soon let you know if the mirror-flops (mirror overrun problem) has disappeared.

It took 13 days from the day I sent it in to its return today. Not bad in my opinion. Just hope the problem is gone for good so I can get back to enjoying using the K5. More to come...

September 27, 2011 - So Far, So Good
My K5 has been performing flawlessly since it returned from CRIS in Arizona. I wish I had a definitive answer as to what they had to do to repair it but I know that will not be disclosed. Mirror Flops are gone and I am enjoying using the K5 again.

Here is the repair status they posted on their website for my camera.


Jim Radcliffe

Videos Which Demonstrate The Mirror Flops

The first video is not of the best quality but shows the issue with a K5.

The second video is the most extreme example of the mirror flops I have come across to date. The camera is the Pentax K-r and the video was made on July 16, 2011. While my camera's symptoms are not as extreme as this, they are the same but ONLY when a fully charged battery is in my K5.


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