In answer to your question The one Nadeem, the Lithium battery is the genuine Pentax original.

I have to report that yesterdays optimism was premature. The mirror flap has definitely stopped but the fake exposure still rules. However it is intermittent and I have just managed four consecutive shots before it kicked in. I feel it must be a firmware issue so I will go back to the old threads for help. I am using firmware update v1.15, which was installed in 2014 when the camera went back to Pentax for repair. I might try going back to v1.14 and see if that makes any difference,

Bob

Having recently fixed the problem of aperture block on my K-r ( thanks to the excellent videos on YouTube), I have been frustrated with other exposure problems. As Mirror flap was one of them, I searched the Forum and found several threads dating back to 2014, I found that many folk were having exactly the same symptoms as me on much newer and more expensive models. The threads ended with a discussion about the role of the Lithium battery in all this. As those threads have become dead I thought I should make a contribution to the topic by way of a new thread. There may be new generation of 'mirror flappers' who might benefit from this.

I was experiencing fake exposures, when up to 10 secs would elapse between the mirror action and the shutter action but resulting in no image being recorded. After that the dreaded mirror flap took over. The mirror action would happen when the camera was switched on and every button press after that, including raising the flash. If a button was held down thee mirror action continued. I concluded it must be a firmware problem and reinstalled v1.15. The Pentax instructions for this insisted that the Lithium battery should be fully charged before starting, which I did and left it in the camera. This improved some of the issues but not the mirror flap. As the other thread included discussion on the tested battery voltage being higher than specified. Mine showed 7.85v when tested. I also tested my AA battery holder with freshly charged Eneloop batteries. They were 5.5v and I tried them in the camera. To my surprise and delight no mirror flap and no fake actions just normal exposures. I need to test it more thoroughly tomorrow. I then put the Lithium battery in and immediately the problems came back. The battery indicator first showed solid green, I made one exposure and it turned red. I made another exposure and it turned yellow At the moment that is all the proof I need to blame the Lithium battery for my sleepless nights. I note that the battery was not made in Japan.

Best wishes, Bob

Good news and very bad news. I was able to do the magnet filing on Sunday afternoon in about two hours. Was much easier than I had expected. On first test I thought it was working fine until I realised I had not engaged the AF/M button with the switch inside. I had to dismantle the camera again and make sure the button was in the right place. When I then started testing again I found real problems with the exposure. I won't describe all the ways I tried to determine what was causing the problem but just summarise the general effects.

Using a 50mm lens with an aperture ring set to the A position, the camera starts on it's capture cycle and then stalls for 5-10 secs before the shutter opens. With the lens off I watched this sequence. When the shutter release is pressed the diaphragm trigger rises a little way and the mirror is raised then after the pause the shutter opens and closes normally but no image is taken at all. The same thing happens using a DA lens.

Using the 50mm lens in any manual aperture position produces a well exposed image. The review screen always shows f1.7 the max aperture but by watching the lens aperture in action it was stopping down. Without checking the manual, I think this is normal for non-DA lens. So the problem revolves around the automatic exposure system.

I have wiped the camera and lens contacts but they are passing the AF signals anyway. I reset the settings and checked the custom settings and the only thing I am thinking of doing is reinstalling the firmware. I don't think my work on the aperture block could have caused this issue but who knows (no black exposures).

I am hoping that someone may recognise this problem and suggest a remedy.
Thanks for reading this catalogue of woe.

Bob

I was pretty sure it is the aperture block problem, so I took it to a repairer in Bristol. I explained the fix that was well detailed on a YouTube video that had proved successful but he didn't buy that and wanted to send it to Pentax. I now have to bite the bullet and do the job myself. First I have to find out more about the filing operation. Is it to reduce the length of the magnet or just to clean the ends to improve contact. The video shows the ends finely polished so my guess is the latter purpose. I will let you know how I get on.

Bob

Thank you Richard, from reading the other thread I know you are an expert on this subject.
I don't normally use manual mode so I'm having to read the manual to get consistent results. I'm working on it.

Bob

Thanks for that lead David, as I wasn't aware of the aperture block issue. I have looked up the thread about the K30/K50 and it mirrors my experience very well. My K-r precedes the K-30 by a couple of years so it's disgraceful that Pentax allowed it to affect so many models. I have tried some of the suggestions and some of them work. Setting an aperture of f32 worked and so did using an old manual lens. I think my results confirm that it is the dreaded aperture block and I shall have to consult a repairer. It's obvious from the posts that contacting Pentax is useless, which is very disappointing and undermines my confidence in the current Pentax brand.
I may add to the other thread as well as this one if I make some progress.

Kind regards, Bob

My K-r is producing very underexposed (black) images. Out of the 50 or so test shots I've taken, about seven have a very faint image. When I switch on the bright/dark setting, in both review and playback, this shows that the basic features of all the images are recorded to a limited extent. All the images were taken in program mode and some of the exif files/properties show aperture/time/ISO settings which could have been suitable for the subject. I have tried a variety of possibly camera settings, SD card re-format, reset and a manual lens to exclude lens coupling. I am now wondering if it is a software problem. I did let the battery drain to exhaustion and maybe that corrupted the software.
Any similar experience or ideas will be most welcome.
Thanks Bob

This charger is clearly what I need to get the best from my Eneloops, although I may need a new set if mine can't be improved. I have to weigh the cost against my usage as I don't use my cameras now as much as I would like. I might check Ebay for a used one. I'm so glad that the two models I have can take AA batteries as it means they will never become obsolete. I have a 10 year old Panasonic FZ30, which still takes excellent images with it's Leica lens but if the batteries pack up so does the camera.

I think we have now come to the end of exploring this problem. I have been surprised at the number of you that have contributed helpful comments. It has been a very worthwhile exercise from my point of view and I hope you all benefited to some extent. A hearty thanks to all of you for kind and generous interest.

Kindest regards, Bob

Thank you Karlo, Martin ,John, Sebas77 and Algi for your extra comments, They all add to my understanding of the problem, one way or another. I do appreciate your time and trouble very much. I will try and reply to the points you have all made in this one post, without too much repetition.

Karlo, the date on them is 12-2030, so they should have been good but were made in Singapore!!
Martin, the retailer will give me a refund. They need to check out their stock in case it is a dud batch. Your experience with the K-x is interesting. When using Eneloops the red battery indicator would show empty but I could go on taking shots for quite some time. Both you and Algi have referred to using an intelligent or suitable charger. I have to admit that when I started using Eneloops I ignored Sanyo's advice and used the ultra -fast charger I had. This may have damaged the performance of the batteries. I have a Fameart slow charger that I will now try, if it's not too late. I have three sets of Eneloops, which I would like to go on using, if I can get a better performance from them. I will check getting a charger from Panasonic. If not, I now know what the options are, thanks to your help.

Kindest regards, Bob

Thanks for your persistence John, in trying to help. You will be interested to hear that I have now proved that the batteries are dud. I tested them under load and the meter first reported a voltage of 6.4 and then started jumping through a random cycle of lower values right down to zero and back again. This explains why I was able to take a few shots before they hit zero and stopped the camera. This was not what I had expected from set of batteries from a well known make. They will be returned.

On the other points you mention, I had discounted the 'alkaline' option and the firmware is up to date. These lithium batteries are not rechargeable or that could have been an option.

Thanks again for your help. Kind regards, Bob