[reh321]

Just saw this thread and wanted to join to reply. Bought my K70 Sept 17, 2017 and have take around 3400 photos. Mine failed last week. Looks like aperture block failure as well, but mine went all at once and never intermittently came and went. Very disappointing.

Could you post a couple of dark images from it?

Evidence of actual problem with K70 would be very good.

[The Squirrel Mafia]

Has anyone taken a K-70 apart and actually looked at the mechanism?
That is the only way to be certain it is the same mechanism.

This would be the only way to find out, but I don't think anyone will do this anytime soon, since the majority of them will be under warranty.

[reh321]

This would be the only way to find out, but I don't think anyone will do this anytime soon, since the majority of them will be under warranty.

Hopefully, the accompanying paperwork will be informative, and someone will share that information with us.

[stevebrot]

It is unfortunate that neither owner checked the actual aperture to confirm the source of the failure. The OP stated that metering was funky, but that could be taken several ways. The gold standard for diagnosing aperture block failure is to put the camera in M mode (auto ISO off, aperture ring not being used) with aperture set wide open and shutter speed at something slow (e.g. 1-2 seconds). Release the shutter while observing the aperture opening through the front of the lens.* Anything other than the aperture remaining wide open is indication of a problem with the controller. If the problem has been intermittent, it may help to do the test after a period of non-use. Even one failure is significant.

Edit and contrition: I forgot to review @CodyH 's posts on other threads regarding their problems. As it turns out they did check actual aperture function and have contacted Ricoh/Pentax for warranty service. The contrition is that I was part of the discussion on the other thread and did not double check that it was not the same user.


Steve

* This method was instrumental in diagnosing the initial wave of aperture block failures on the K-30 and narrowing the cause to a fault in a mechanical component rather than electronics.

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Last edited by stevebrot; 10-05-2018 at 01:12 PM.

[reh321]

It is unfortunate that neither owner checked the actual aperture to confirm the source of the failure. The OP stated that metering was funky, but that could be taken several ways. The gold standard for diagnosing aperture block failure is to put the camera in M mode (auto ISO off, aperture ring not being used) with aperture set wide open and shutter speed at something slow (e.g. 1-2 seconds). Release the shutter while observing the aperture opening through the front of the lens.* Anything other than the aperture remaining wide open is indication of a problem with the controller. If the problem has been intermittent, it may help to do the test after a period of non-use. Even one failure is significant.

Steve

* This method was instrumental in diagnosing the initial wave of aperture block failures on the K-30 and narrowing the cause to a fault in a mechanical component rather than electronics.

Isn't this the method @CodyH reported four days ago?

Yes aperture block failure of some kind. I've tested 3 lenses on it and set shutter speed to 2 seconds and looking down the lens from the front there is no difference in the aperture blades(they close all the way down) regardless of setting. All pictures are very dark even outside on ISO3200. Sad thing is I'm 15 days out of warranty. Now I'm not a professional or a camera tech, but from everything Ive read, that's what I'm dealing with.

[stevebrot]

Isn't this the method @CodyH reported four days ago?

Yes, I do believe it is. Thanks for reminding me that it is the same CodyH from both threads. They did confirm an aperture control issue that will hopefully be repaired under warranty. I guess that is one of the hazards of cross-posting an issue on multiple threads. The other larger issue is that such amplifies an isolated issue into "multiple reports on the web".

To the best of my knowledge, CodyH's report is the first verified for the K-70 for aperture control issues on this site. With any luck their camera will be repairable at no cost and it will be reported back here (or on the other thread) what parts were replaced.


Steve

(...previous comment edited...)

[CodyH]

Could you post a couple of dark images from it?

Evidence of actual problem with K70 would be very good.

If i still have any on my memory card i'd be happy to post them and would most likely do it on the new post made by @Stevebrot about under exposed photos on the K70

Hopefully, the accompanying paperwork will be informative, and someone will share that information with us.

I will share any information that the repair shop provides me.

Yes, I do believe it is. Thanks for reminding me that it is the same CodyH from both threads. They did confirm an aperture control issue that will hopefully be repaired under warranty. I guess that is one of the hazards of cross-posting an issue on multiple threads. The other larger issue is that such amplifies an isolated issue into "multiple reports on the web".

To the best of my knowledge, CodyH's report is the first verified for the K-70 for aperture control issues on this site. With any luck their camera will be repairable at no cost and it will be reported back here (or on the other thread) what parts were replaced.


Steve

(...previous comment edited...)

Yes, I apologize for making duplicate posts. I was responding to 2 separate threads and was frustrated shortly after the failure occurred. I have sent the camera off to Precision Camera and contacted Ricoh USA and they have contacted Precision on my behalf. I will provide all further updates and information on the new post about the concern.

[stevebrot]

I have sent the camera off to Precision Camera and contacted Ricoh USA and they have contacted Precision on my behalf. I will provide all further updates and information on the new post about the concern.

Yay! I hope they can fix it for you without charge and that can find out what went wrong.


Steve

[photogem]

Testing aperture block failure in M-Mode (i.e. golden standard):

I don't understand why I never became aware of this because this should have "jumped into my awareness".
Possibly because I always did the test in simple Av-mode or TAV-mode.
Usually I take a F50/1,7 or similar and set it wide open = f1,7 and do a test shot:
Picture very dark = stuck solenoid
Then the (logical) opposite test, in this case f22 + test shot:
Picture fine (because the solenoid doesn't have to open!)

The other easy way of testing is liveview as I have explained:
Right away when set on liveview a Pentax with functioning solenoid will set itself to f4 i.e. relative open
Aperture - Wikipedia

But with stuck solenoid the iris will remain closed = f22 and will
look like this

I have already done tests checking the function of the solenoid when using the green button which is in M-Mode.

So today I had the chance to repair another K30 and finally did the test.
The iris did nothing after I followed those instructions.
So I opened the K30 to check it inside.
I unsoldered the wires: No change.
I built the white solenoid in: No change

So to test it again I opened a K100D. The K100D is a bit more difficult to test with seeing the solenoid in action because one has to reassemble it partly for being able to install the batteries.

I intentionally took a working K100D with high shuttercount because I then installed the bad green solenoid into this K100D!

The result was as expected: As well in the K100D the solenoid will not act in M-Mode!

On this photo of the K100D with the faulty solenoid from the K30 you can see one cable of the solenoid unsoldered:


It doesn't matter if the solenoid is faulty, soldered or unsoldered, has a filed plunger or not, you even can take the solenoid out completly, the camera will still work in M-mode because in M-Mode the solenoid is not working.

As explained in the previous tests here:
Dark exposure problems on K-30 or K-50? Discussion Thread - Page 20 - PentaxForums.com

[reh321]

I used large fonts and bright colours to point at something very important. Because this socalled
"gold standard for diagnosing aperture block failure" cannot work.

The reason for labeling this The "Gold Standard" is the fact that you see the aperture working / not working without opening the camera. I originally labeled the problem "Dark Image Syndrome" because - like a human 'Syndrome" such as AIDS - original diagnosis was based on symptoms, while the "Gold Standard" diagnosis is based on watching the mechanism which leads to the symptoms. Observing mechanism is better than observing symptoms, and not having to open is better than opening.

[R peeke]

I have a pentax k-r white body wich appears to be showing signs of aperture block failure but looking on the internet there does not apear to be any mention of anybody else suffuring wth this in a k-r. Has enybody else had or heard of this issue with a K-r.

[reh321]

I have a pentax k-r white body wich appears to be showing signs of aperture block failure but looking on the internet there does not apear to be any mention of anybody else suffuring wth this in a k-r. Has enybody else had or heard of this issue with a K-r.

No - in fact, I believe K-X is a usual donor of a good 'white' solenoid for a more modern camera.

In order to diagnose this problem, we suggest that you observe the aperture directly as explained by @stevebrot

The gold standard for diagnosing aperture block failure is to put the camera in M mode (auto ISO off, aperture ring not being used) with aperture set wide open and shutter speed at something slow (e.g. 1-2 seconds). Release the shutter while observing the aperture opening through the front of the lens.* Anything other than the aperture remaining wide open is indication of a problem with the controller. If the problem has been intermittent, it may help to do the test after a period of non-use. Even one failure is significant.

* This method was instrumental in diagnosing the initial wave of aperture block failures on the K-30 and narrowing the cause to a fault in a mechanical component rather than electronics.

I would also suggest that you post an example photo here {with EXIF still intact} so we can see what makes you think you have a problem.

[photogem]

The reason for labeling this The "Gold Standard" is the fact that you see the aperture working / not working without opening the camera. I originally labeled the problem "Dark Image Syndrome" because - like a human 'Syndrome" such as AIDS - original diagnosis was based on symptoms, while the "Gold Standard" diagnosis is based on watching the mechanism which leads to the symptoms. Observing mechanism is better than observing symptoms, and not having to open is better than opening.

But it is the wrong approach!
As you yourself have often explained and proved:
Your K-30 with stuck solenoid works in M-Mode!

So please explain: If the solenoid is not used in M-Mode, how can one test it in M-Mode?

The easiest test is in AV-Mode:
-wide open: dark photo

- completly closed aperture/full stopped down: photo must be 100%

Second check using Liveview:
- set camera in AV-Mode.
- look into the front of a lens which allows you to see the blades
- switch Liveview on: If the lens closes completly i.e. stoppes down (for example f22): Solenoid is stuck
- if the lens closes to f4,0: solenoid works

Those methods are simple and straight forward and go right to the root, i.e. THE ONLY PROBLEM in 99% of all dark exposure problems with all Pentax bodies using a solenoid: The solenoid which is stuck!

I have attached 2 short videos recording the function of the solenoid in a K500:
1. AV-Mode: One can see the movement of the white plastic wheel (right) AND the plunger of the solenoid (as it should be if the solenoid is alright)
2. M-Mode: One can see the movement of the white plastic wheel as it should be but the plunger of the solenoid does not move in and out.
Here I set the camera intentionally to 1sec..


There is a "resonance" in the plunger of course (which one wouldn't see if lets say 1/60sec) but this resonance comes from the movement of the complete aperture block and all those other parts moving.

But the solenoid itself does not actuate, the plunger stays peacefully in place.

[malc77]

I definitely have the aperture block problem on my K30, and have read many threads. I can dismantle the camera to reach the solenoid block - if I remove and then de-magnetise the horseshoe armature, will that make matters better or worse? If it is soft iron it would not need to be magnetised to be attracted by the coil windings. Also, I cannot understand why the block will work after a few actuations, then not work the next day until a few more actuations are made. Mine is the green solenoid of course, would polishing the armature (rather than fling bits off it improve matters?) I apologise if these questions have already been answered- the seem numerous posts and my eyesight sin't too good. Thanks!

[krgroothuis]

I definitely have the aperture block problem on my K30, and have read many threads. I can dismantle the camera to reach the solenoid block - if I remove and then de-magnetise the horseshoe armature, will that make matters better or worse? If it is soft iron it would not need to be magnetised to be attracted by the coil windings. Also, I cannot understand why the block will work after a few actuations, then not work the next day until a few more actuations are made. Mine is the green solenoid of course, would polishing the armature (rather than fling bits off it improve matters?) I apologise if these questions have already been answered- the seem numerous posts and my eyesight sin't too good. Thanks!

The only real fix is: buy a white solenoid via internet or use a donor K-X or older model Pentax. And replace the green solenoid with that white one.

I did this with my aperture failure block suffering K-S2.