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01-07-2019, 09:10 AM   #31
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Another Australian member reports having purchased a K-30/50 (I don't recall which) from the US which had/developed the aperture problem. The US vendor refunded the purchase and told him to keep the camera rather than go through the expense and trouble to return ship it. The PF member contacted CR Kennedy who told the member that the failure was a known problem and since the camera was purchased from an authorized dealer would be covered as a warranty repair. The camera was repaired.

My suggestion to @fernoh123 is to contact CR Kennedy on both the K-30 and K-70.

01-07-2019, 08:32 PM   #32
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Thanks, @Not a Number, I think I will do that. It occurred to me that the third-party warranty was somewhat of a hindrance in my case, since I had one camera under warranty and one not. So best to check out CR Kennedy first, to get their opinion.


Cheers,
Peter
01-14-2019, 08:56 PM   #33
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QuoteOriginally posted by fernoh123 Quote
I now find my K-70 is exhibiting symptoms of the same failure.
Might you elaborate on what you are seeing? Have you confirmed that aperture control is failing by checking if the lens stops down when set to remain wide open?

FWIW, this thread is in the K-70 sub-forum and is intended for reporting and documenting issues with the K-70 aperture control only. Complaints or descriptions or comments regarding the K-30/K-50 other models are off-topic and sort of muddy the waters when trying to document your report.


Steve
01-14-2019, 09:45 PM   #34
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QuoteOriginally posted by fernoh123 Quote
After losing my K-30 to the aperture control block problem (not verified since I decided not to repair, but 99.99% certain as to cause), I now find my K-70 is exhibiting symptoms of the same failure. The only modern lens I can use (on either camera, after updating K-30 to K-50 firmware) is my Pentax-DA 55-300 ED PLM WR lens, the one with electronic aperture. In fact, using this lens probably hid from me the early signs of the failure as I rarely use other lenses now
Actually, using a KAF4 lens might speed development of what I call Dark Image Syndrome, because it doesn't use the body's Aperture Control Mechanism. Anecdotal evidence indicates that failing to use that mechanism may cause it to fail sooner {use it or lose it}

01-28-2019, 07:13 PM   #35
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Trouble has seemingly popped up at shot number 7995.
I do at least still have extended warranty.
And later if it fails again after warranty when using an aperture ring and green button should work, right?
It's been a while since I learned about aperture block failures back before I bought my camera, So I don't remember it all (should've made notes)

Is there any possibility this is a lens issue?
I was using a SMC A 50mm (I will try my other lenses too)

I went out today to take a photo, and the first photo was significantly underexposed, photos after were fine.
later after it was off for a while; the first photo was also significantly underexposed, then photos after were fine.



1st shot 1/200th 1.4 AV


2nd shot 1/200th 1.4 AV

Last edited by pentax360; 01-28-2019 at 07:20 PM.
01-30-2019, 01:35 PM   #36
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QuoteOriginally posted by pentax360 Quote
Trouble has seemingly popped up at shot number 7995.
I do at least still have extended warranty.
And later if it fails again after warranty when using an aperture ring and green button should work, right?
It's been a while since I learned about aperture block failures back before I bought my camera, So I don't remember it all (should've made notes)

Is there any possibility this is a lens issue?
I was using a SMC A 50mm (I will try my other lenses too)

I went out today to take a photo, and the first photo was significantly underexposed, photos after were fine.
later after it was off for a while; the first photo was also significantly underexposed, then photos after were fine.



1st shot 1/200th 1.4 AV


2nd shot 1/200th 1.4 AV
I think you need to make it a warranty repair.
01-30-2019, 03:15 PM   #37
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QuoteOriginally posted by pentax360 Quote
Trouble has seemingly popped up at shot number 7995.
I do at least still have extended warranty.
And later if it fails again after warranty when using an aperture ring and green button should work, right?
It's been a while since I learned about aperture block failures back before I bought my camera, So I don't remember it all (should've made notes)

Is there any possibility this is a lens issue?
I was using a SMC A 50mm (I will try my other lenses too)

I went out today to take a photo, and the first photo was significantly underexposed, photos after were fine.
later after it was off for a while; the first photo was also significantly underexposed, then photos after were fine.

1st shot 1/200th 1.4 AV

2nd shot 1/200th 1.4 AV
This sounds like the aperture control failure; have you 'tested' it?
QuoteOriginally posted by stevebrot Quote
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.
In any case, if you have warranty protection, then you should definitely use it - if possible, it would be good to get feedback from them about what they found and what they did about it.
02-07-2019, 02:29 PM   #38
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FWIW, having just bought a K-70 from a UK (SRS) Pro Dealer means it has a 2yr warrantee, and I hope that it will well-outlive that period without APB problems - but I'll be keeping that old MZ-5 that I bought a few months ago - and with, hopefully, a white solenoid! - in reserve (or even the white one in the "fixed" K-30/"K-50"!) in order to get the K-70 fixed by our local Pentax specialists (Asahi Photo in Brentford, London) in a few years time.

PS: Obviously I was fully aware of the APB issue before buying the K-70 - but I LIKE the K-30/K-50/K-70 line and am willing to live with the possible consequences in a few years


Last edited by jeallen01; 02-07-2019 at 02:56 PM.
03-26-2019, 01:02 AM - 1 Like   #39
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Sorry I haven't posted any updates until now.

I've taken about 300 photos, since my post.
So far the worst it's been is 3 underexposed shots in a row and then subsequent shots are fine, then when it’s powered off for a while it happens again.
It does this about 50% of the time.

It’s done it with various lenses so it’s definitly the body.

I've waited to send it in because I wanted to make sure the problem was constant before I sent it in so the techs wouldn't overlook it.
And because it’s been easy to deal with at this point.
04-01-2019, 07:10 AM   #40
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QuoteOriginally posted by fernoh123 Quote
After losing my K-30 to the aperture control block problem (not verified since I decided not to repair, but 99.99% certain as to cause), I now find my K-70 is exhibiting symptoms of the same failure. The only modern lens I can use (on either camera, after updating K-30 to K-50 firmware) is my Pentax-DA 55-300 ED PLM WR lens, the one with electronic aperture. In fact, using this lens probably hid from me the early signs of the failure as I rarely use other lenses now, unless I'm in the bush with my 90 mm Tamron macro. I have a bunch of manual and early K lenses, but don't find the inclination to use them much of the time.


I have a two year no-questions asked third-party Australian warranty on the K-70 so hopefully that repair won't cost me, but my K-30 is now 4+ years out of warranty. The K-70 first exhibited problems 9 months after purchase, at about 8000 images, K-30 at about 5 years (and some 13,500 images).

So here's hoping that all is well, and I get a longer time before failure from the repair to the K-70. In the meantime, I think the 90mm Macro will sit on my still working *ist-DS, and the 55-300 will be on the K-30(-50)!

Peter
QuoteOriginally posted by stevebrot Quote
There have been a couple of recent threads regarding gross underexposure (essentially black) on some or all photos. While it is not fully clear whether these reports are related or (shudder) whether there is an emerging problem similar to the aperture block failure common to the K-30/K-50 models, it seems reasonable to provide a clearinghouse thread in an attempt to determine who is having problems and the evident point of failure. For the sake of clarity and accountability, it would be good to limit experiences to those of our users and not reference claims from other forums or rumor sites.


**********************************

To date, I am aware of the following Pentax Forums users having problems with dark frames:

User @dudesohungry (31 Aug 2018) : K70 ISO problem - PentaxForums.com
Not known if this was an aperture or other problem.

User @drumhead (17 Sept 2018) : Strange behaviour from my K-70...aperture block? - PentaxForums.com
Presumptive aperture control issue. Camera sent for warranty service.

User @CodyH (30 Sept 2018): K-70 aperture motor question - PentaxForums.com
Confirmed aperture control issue with root cause not known. Warranty service may be attempted (camera barely out of warranty). Update -- camera is being sent for service and will probably be covered under warranty.

User @RichFam (5 Oct 2018): K-70 Underexposed Photo Reports - PentaxForums.com
Confirmed aperture control issue with root cause not known at about one year post purchase. Did not seek warranty service.

User @asalwa (11 Nov 2018): K70 aperture block? - PentaxForums.com
Confirmed aperture control issue with root cause not known, August 2018. Out-of-warranty repair was performed, though it is unknown what was replaced/adjusted.

User @Eric_Hall (10 Dec 2018): Dark images - PentaxForums.com
Confirmed aperture control issue with root cause not known with camera to be sent for service under warranty.

User @fernoh123 (6 Jan 2019): K-70 Underexposed Photo Reports - PentaxForums.com. Symptoms similar to aperture control issues with other model cameras.

User @pentax360 (30 Jan 2019): K-70 Underexposed Photo Reports - PentaxForums.com. Dark frames on first few captures of a session. It is unknown whether the cause is due to failed aperture control.

User @SharkyCA (31 Mar 2019): K70 aperture block? - Page 3 - PentaxForums.com. Dark frames interspersed with properly exposed frames (middle two out of four effected). It is unknown whether the cause is due to failed aperture control.



**********************************


Three (initial) similar problems in less that a month's span are a potential cause for concern. Any future reports may be logged here in an effort to determine if these are isolated incidents or evidence of a larger issue. At the very least, this thread may serve to qualify claims of multiple reports from the Web regarding K-70 aperture control problems.

Note: Terminology is important and it is good to be clear on terms. Here are a few starters along with working definitions:
  • Exposure problems: images are over or underexposed. Cause may be anything from user inexperience to hardware meltdown
  • Metering issues: Bad meter readings leading to inappropriate settings
  • Dark Image Syndrome (DIS): Term coined by user @reh321 for unexplained dark frames despite correct settings
  • Aperture Control Failure/Issue: Iris opening during exposure does not reflect set value. Example: Camera is set to wide open, but exposure is made with lens stopped down to smallest opening. This sort of behavior may have many different causes as diverse as damage or failure in the lens itself and water incursion causing damage to body electronics.
  • Aperture Block Failure: This is the specific failure of the so-called aperture block solenoid used for aperture control on a wide span of Pentax SLR bodies dating back as far as the early 1980s. Failure of this component affected a large number of K-30, K-50, and K-500 bodies and was the cause of aperture control failure on those cameras. A similar unit was fitted to the K-S1 and K-S2. It is possible that the K-70 has a similar part, hence this thread.
  • Diaphragm control block : G100 Proper name and part number for the assembly that controls the aperture opening on most Pentax cameras since the early 1980s. "Aperture block" and "Aperture control block" are synonyms in common usage.
  • Diaphragm control block : G200 Proper name and part number for the assembly that controls the aperture opening on flagship models since the release of the K-7. As of 11 Oct 2018, it is not clear whether the K-70 uses this part or the G100 part above.

To test for Aperture Control Failure/Issue:
The gold standard for diagnosing an issue with aperture control 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.
Hopefully, there is no cause for alarm.


Steve

(...not a K-70 owner, but was heavily involved in the first wave of K-30 problems several years ago...)
Hello Steve

Thanks for your reply to my post: K70 aperture block? - Page 3 - PentaxForums.com

I have not gone through your "Gold Standard" as the problem I documented in my post is not the first occurrence of "dark" images I have had but the first time it has happened on the same day with the same lens with relatively the same camera settings and light conditions.

The pictures on my Flickr page give a full breakdown through EXIF as to the time,settings,F stop and other incidentals. Flickr link: Aperture Block | Flickr

The 4 photos in the series img0283 was shot at 10:30 a.m. and then img0284 & img0285 was shot at 4:46:44 & 4:47:02 p.m. respectfully with the last shot img0286 at 4:47:20
As of this morning I have had one more shot that was dark, first of the day after setting camera back to "factory reset" Link to that one is here: https://www.flickr.com/photos/sharkyca/33638115178/in/album-72157690684736063/



Aperture Block | Flickr

I will be looking into contacting Ricoh/Pentax to see if my Canadian warranty applies, although I bought it through a US distributor.

Any input gratefully received, thanks
Norm
04-01-2019, 10:44 AM   #41
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QuoteOriginally posted by SharkyCA Quote
I have not gone through your "Gold Standard" as the problem I documented in my post is not the first occurrence of "dark" images I have had but the first time it has happened on the same day with the same lens with relatively the same camera settings and light conditions.
Well, then I guess you won't know if it is a shutter, or an aperture control problem without sending it in. It is a simple test (takes less time than the documentation in your post), but whatever is right. As for your warranty, it is my understanding that Ricoh/Pentax Canada will only provide the Canada warranty for a camera purchased from an authorized Canadian dealer where the owner also has a Canadian address. Similar rules apply for U.S. cameras. The issue, as I understand it, is clearing customs and the cost of return shipping.

If you do have the camera repaired and if able, do try to get a detailed description from the shop as to what they did and what parts were replaced and post back here to close the loop. I know this sounds persnickety, but actual documented failures of the Diaphragm Control Block on the K-70 being incredibly rare at present and lack of evidence that it actually shares the same component with previous models make it difficult to suggest that Ricoh to "step up" and accept responsibility.

Again, I hope you are able to get your camera working properly.


Steve
04-01-2019, 05:24 PM   #42
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QuoteOriginally posted by stevebrot Quote
Well, then I guess you won't know if it is a shutter, or an aperture control problem without sending it in. It is a simple test (takes less time than the documentation in your post), but whatever is right.
I have done your "gold standard" test and aperture appears to function, as does the shutter, so I have sent an inquiry to Pentax with my report. I do believe if it was a "shutter" problem there would be "no image" as apposed to a dark image with the EXIF showing f-stop @ f4.5 and f5 as it is in the images I shared on my flickr page. Images taken in same ambient light, approximately.
04-01-2019, 06:58 PM   #43
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QuoteOriginally posted by SharkyCA Quote
I have done your "gold standard" test and aperture appears to functio
Try again after a period of inactivity. If there is an issue with aperture control, it will show itself with an inappropriate stop-down.


Steve

Last edited by stevebrot; 04-01-2019 at 08:23 PM. Reason: Completeness
04-01-2019, 08:23 PM - 1 Like   #44
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QuoteOriginally posted by stevebrot Quote
Try again after a period of inactivity.
To elaborate a bit...

I did not coin the "gold standard" term directly. It came about as a result of group troubleshooting the first wave of K-30 failures (almost all were just out of warranty) as a means of determining just what was happening with their cameras. In some cases, it was an issue with both mirror and aperture control due to electronic issues. In other cases, there was water incursion. In a few others, it was shutter timing. Damaged lens couplings and lazy apertures were also in the mix as was user error in the form of misuse of spot metering and not knowing one was set to do bracketed exposures.

Eventually it became clear that the majority of reports were due to dramatic failure of aperture control with repair reports stating that the Diaphragm Control Block was replaced. A simple screen to check aperture stop-down from a full-open state became the first step in differential diagnosis with a possible confirmation with a second lens. Several years later, self-repair efforts, mostly by owners in Germany, pinpointed the faulty component as a solenoid operating as part of the larger controller block mechanism. Not too long afterwards, people troubleshooting an unrelated problem with the original A-series Super Program camera provided an illustration showing a diaphragm controller essentially identical to that used in the K-30/K-50. Further research revealed the same controller was used on all Pentax SLRs (film and digital) until the Pentax K-7 in 2009. From the K-7 forward, flagship models had a different mechanism than the lower and middle line bodies; those lines continued with the tried and true mechanism which had proven itself exceptionally durable for decades*.

In retrospect, the failure of that mechanism in a significant percentage of the K-30/K-50 production was apparently completely unanticipated. This was complicated by the fact that the failure is age and not usage determined. Warranty repair trends come to the attention of QA; with most of the failures occurring at 18 months or more after purchase, the failed components would not have been sent to Ricoh. That, and nature of production cycles contributed to the persistence of components in the supply stream that tested good, but failed with age. The whole matter is quite sad, though it is quite heartening to see far very reports in the K-S1 and K-S2 and, up until recently (some two and half years after release), no reports on this site of dark frames on the K-70.


Steve

* I own a early 1980s Pentax Super Program whose diaphragm controller block continues to work quite well more than 35 years later...solenoid included.

Last edited by stevebrot; 04-02-2019 at 08:18 AM. Reason: Completeness and grammar
04-02-2019, 07:32 AM   #45
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QuoteOriginally posted by SharkyCA Quote
I have done your "gold standard" test and aperture appears to function, as does the shutter, so I have sent an inquiry to Pentax with my report. I do believe if it was a "shutter" problem there would be "no image" as apposed to a dark image with the EXIF showing f-stop @ f4.5 and f5 as it is in the images I shared on my flickr page. Images taken in same ambient light, approximately.
The K-30/50/S2/70 line of cameras is Pentax's "consumer" line - I'm not sure exactly what Ricoh expects of this line, but clearly they don't have {nor do they charge for} the same longevity expectations that they have for the K-7/5/3 line. While everyone seems to be focused on the aperture control mechanism, it turns out that consumer line cameras can suffer from other issues (*) also, which if why we need to do a proper diagnosis to be sure that the right repair is performed.


(*) For example, several people are dealing with a problem which looks similar, but may be quite different - possibly a bad exposure sensor in the prism housing; in their case LV gives good exposures but using the viewfinder doesn't. Usually helpful respondents start talking about replacing the solenoid first, and ask questions only later. At least one of those users appears to have left in frustration after Pentax provided a fix for the aperture control problem, but the actual camera still didn't work correctly.
K-50 pictures are black when taken through viewfinder, but not in live view - help - Page 2 - PentaxForums.com
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