As of today, 28 December 2019, I will no longer be maintaining this report page.

The incidence is sufficiently low that it hardly makes sense, but it has been an interesting experience.

Steve

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

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.

NOTICE: This thread is curated and keeping track of pertinent reports and updates will be easier if we abide be a few simple rules. Please use this thread for:

• Reports of problems with underexposed or dark frames from Pentax Forums users. Please include written details and whether you were able to confirm that it is an issue with aperture control (see below for instructions).
• Updates regarding cause, repairs, and repair details (when known)

Do NOT use this thread for:

• Discussion of the aperture control block problem on K-30/K50/K500 models or reports for any model other than the K-70
• Troubleshooting poor exposure. A separate thread in the K-70 subforum or in the troubleshooting section of the site might work better.
• Photos of dark frames. If it is happening, your word is enough. Photo examples, even with full EXIF, are of limited or no value for troubleshooting or confirmation.
• Complaints about Ricoh/Pentax product or service or business practices
• Complaints or comments about the K-70 in general
• Complaints about repairs from authorized facilities, including: timeliness, cost, outcome, or communication

In regards to the last three points, neither Ricoh/Pentax nor the authorized repair shops they contract with monitor activity on the Pentax Forums site.

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

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. Unknown whether repair was sought.
Confirmed Camera was sent for warranty repair with root cause confirmed as aperture control block failure by statement of work performed.

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.
Confirmed aperture control issue with root cause determined to be diaphragm control block. Dark frames interspersed with properly exposed frames (middle two out of four effected in initial report and many in subsequent discussion). User sent camera to Sun Camera in Canada where they confirmed the diagnosis.

User @disasterfilm (16 Jun 2019) New K-70 - Metering issues between Live View and OVF - PentaxForums.com originally reported as dark frames when using optical viewfinder only. This is apparently a metering issue, but is recorded here just in case.

User @Alex74 (10 Jul 2019) K-70 Exposure issues - Page 3 - PentaxForums.com
Ambiguous Aperture actuation problems of unclear nature (based on repair report); root cause ambiguous...repair report "exchanged aperture mechanism and controller". User initially reported severely underexposed as well as overexposed frames despite no change in camera settings. Initially it was unknown whether this was a problem of lazy aperture or aperture control. Making no assumptions, I trust that the problem has been fixed. Report is retained in the interest of making as complete a count as reasonable.

User @rwhynacht (15 Aug 2019) New K-70 - Metering issues between Live View and OVF - PentaxForums.com
Confirmed aperture control issue based on repair outcome; root cause ambiguous...repair involved replacement of Aperture Control Assy and Resistor Chip. NOTE: This camera had been recently purchased.
Severely underexposed photos in auto exposure modes that, though unclear whether the issue is metering or something else, but included here just in case. The camera was serviced with report noted here.

User @tanz (23 Aug 2019) K-70 Underexposed Photo Reports - Page 7 - PentaxForums.com reports severely underexposed frames when using the optical viewfinder with live mode not having obvious problems. Likely aperture control failure based on description of stop-down behavior.

User @riverrock (9 Sept 2019) https://www.pentaxforums.com/forums/193-pentax-k-70/377096-k-70-underexposed...ml#post4721041
Confirmed Aperture Control Failure/Issue, root cause unknown. Reports severely underexposed frames with visual confirmation of inappropriate aperture stop-down.

User @davedyer (12 Sept 2019) first picture is dark - PentaxForums.com
Confirmed aperture control failure/issue, root cause unknown. Reports underexposed first frame with properly exposed frames thereafter with visual confirmation of inappropriate aperture stop-down.

User @corbinco2 (25 Oct 2019) https://www.pentaxforums.com/forums/53-pentax-dslr-camera-articles/377096-k-...ml#post4778685
Confirmed aperture control failure/issue, root cause unknown. Consistent dark frames after two years ownership confirmed as aperture control problem by visual inspection.

User @Progbusters (19 Nov 2019) https://www.pentaxforums.com/forums/53-pentax-dslr-camera-articles/377096-k-...ml#post4818734
Confirmed aperture control failure/issue, root cause unknown. Consistent dark frames after a few months ownership confirmed as aperture control problem by visual inspection. Grey market purchase with unknown warranty options. User opted to not repair and sold camera "as-is".

User @photogem (23 Dec 2019) https://www.pentaxforums.com/forums/53-pentax-dslr-camera-articles/377096-k-...ml#post4870093
Confirmed aperture control failure/issue corrected by user replacement of solenoid. Failure at after one year ownership, camera still under warranty.


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


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 so-called 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...)

[Not a Number]

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.

A poster on the German Pentaxians forum claims a Pentax/Ricoh rep told him/her the K-30/50 was designed to last 4-5 years. I would guess that is/was the design expectation of consumer level bodies.

See second post by "Padre" and replies below:
(google translate)
https://translate.google.com/translate?hl=&sl=de&tl=en&u=https%3A%2F%2Fwww.p...7760&sandbox=1
(original German)
https://www.pentaxians.de/viewtopic.php?nxu=40456504nx51499&f=76&t=14962&p=5...pentax#p507760

---

Last edited by Not a Number; 04-03-2019 at 03:09 AM.

[SharkyCA]

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.

I would like to take a moment to thank you Steve for your self sacrifice in the "aperture" problem with the Pentax line. I'm sure you have spent a lot of time on this issue.

Your comments and suggestions are greatly appreciated.

I have only had one more dark images since my previous post's and have uploaded it to my Flickr page should you like to take a look.
Thanks Norm.
https://www.flickr.com/gp/sharkyca/5zc77H

[stevebrot]

I would like to take a moment to thank you Steve for your self sacrifice in the "aperture" problem with the Pentax line. I'm sure you have spent a lot of time on this issue.

Multiple people here at PF and on other forums helped assist people with failing cameras and I believe that it was our pleasure in general to do so. Thank you for your appreciation.


Steve

[stevebrot]

A poster on the German Pentaxians forum claims a Pentax/Ricoh rep told him/her the K-30/50 was designed to last 4-5 years.

That should not be surprising, though the usual qualifier is "under average use". Sadly, the same applies to personal computers, tablets, cell phones, and many appliances. Those intended for professional/business use are not a whole lot better. Consider that in the U.S., computers and cameras are fully depreciated at five years for tax purposes.

This rabbit hole is so very off-topic!


Steve

[reh321]

That should not be surprising, though the usual qualifier is "under average use". Sadly, the same applies to personal computers, tablets, cell phones, and many appliances. Those intended for professional/business use are not a whole lot better. Consider that in the U.S., computers and cameras are fully depreciated at five years for tax purposes.

This rabbit hole is so very off-topic!

Steve

I guess I started this so-called "rabbit hole" by my comments that so many things could, and sometimes do, go wrong over time with any consumer-level camera.

The fact remains that any K-n0 exposure failure must be investigated before 'repaired' - too many people do jump to the "aperture control" unit as the source of exposure issues; there is even a reported incident of a service center 'repairing' the aperture control unit, leaving the originally reported issue in place.

My new k50 showed very dark pictures when taken thru the viewfinder, and then a second later repeat the exact same picture, not even moving the camera,nor more making any adjustment, and view it thru live view and the picture is fine. Auto, scene, or manual, does not matter, dark thru viewfinder, good thru live view. Let camera rest and no change, let it rest some more, and all is fine. Tested again today and fine at first, then back to dark viewfinder pictures. Sent to repairs today, as I had passed my return window. Sucks.

Repairs replaced a Diaphramg control block, their spelling, and it is no better.

[SharkyCA]

I would like to take a moment to thank you Steve for your self sacrifice in the "aperture" problem with the Pentax line. I'm sure you have spent a lot of time on this issue.

Your comments and suggestions are greatly appreciated.

I have only had one more dark images since my previous post's and have uploaded it to my Flickr page should you like to take a look.
Thanks Norm.
https://www.flickr.com/gp/sharkyca/5zc77H

I am posting another occurrence (shutter count 4,190) of what I believe is "Aperture Block" first photos out after no usage for a few days are dark again, after a couple of shots problem subsides. First images "imgp0026 & 27 dark imgp0028 ok" then "imgp0033 to 35 dark imgp0036 ok" images can be reviewed here on my Flickr page: https://www.flickr.com/gp/sharkyca/6A4B57

[stevebrot]

I am posting another occurrence (shutter count 4,190) of what I believe is "Aperture Block" first photos out after no usage for a few days are dark again, after a couple of shots problem subsides. First images "imgp0026 & 27 dark imgp0028 ok" then "imgp0033 to 35 dark imgp0036 ok" images can be reviewed here on my Flickr page: https://www.flickr.com/gp/sharkyca/6A4B57

OK...The next time you take the camera out after several days being idle is there any chance you might check to see if the aperture stops down when it should have stayed open? Mount your DA 35/2.8 Macro Limited (easier to see the diaphragm action), camera in M mode, f/2.8, shutter 2 seconds, AF OFF, looking into the lens from the front release the shutter. If it stops down at all, the aperture is not being properly controlled.

Now, back to your photos in the Aperture Block album. Have you noticed that all were taken with the same lens (DA 55-300/4-5.8)? It may just be coincidence, but also may be a red flag hinting of a damaged aperture mechanism in the lens.


Steve

[SharkyCA]

OK...The next time you take the camera out after several days being idle is there any chance you might check to see if the aperture stops down when it should have stayed open? Mount your DA 35/2.8 Macro Limited (easier to see the diaphragm action), camera in M mode, f/2.8, shutter 2 seconds, AF OFF, looking into the lens from the front release the shutter. If it stops down at all, the aperture is not being properly controlled.

Now, back to your photos in the Aperture Block album. Have you noticed that all were taken with the same lens (DA 55-300/4-5.8)? It may just be coincidence, but also may be a red flag hinting of a damaged aperture mechanism in the lens.


Steve

Had not realized they were all DA 55-300 I thought some were other lens, I will do as you suggest and mount my DA 35/2.8 next time out and will track that. The aperture lever on the 300 lens appears to function off camera smoothly but will try your suggestion...Thnks!

[stevebrot]

Had not realized they were all DA 55-300 I thought some were other lens, I will do as you suggest and mount my DA 35/2.8 next time out and will track that. The aperture lever on the 300 lens appears to function off camera smoothly but will try your suggestion...Thnks!

Do consider simply doing a look-see too before you head out. Even a small amount of stop-down when none is set is significant.


Steve

[SharkyCA]

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. Unknown whether repair was sought.

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 so-called 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...)

OK...The next time you take the camera out after several days being idle is there any chance you might check to see if the aperture stops down when it should have stayed open? Mount your DA 35/2.8 Macro Limited (easier to see the diaphragm action), camera in M mode, f/2.8, shutter 2 seconds, AF OFF, looking into the lens from the front release the shutter. If it stops down at all, the aperture is not being properly controlled.

Now, back to your photos in the Aperture Block album. Have you noticed that all were taken with the same lens (DA 55-300/4-5.8)? It may just be coincidence, but also may be a red flag hinting of a damaged aperture mechanism in the lens.


Steve

Do consider simply doing a look-see too before you head out. Even a small amount of stop-down when none is set is significant.


Steve

Hello Steve,I have followed your suggestions and have taken a few photos with my HD DA 35 checking the aperture stop down before taking shots, I did not notice ANY movement in the aperture or any dark photos. I have also used my DA 18-135 lens without any problems.

Today I took about 50 shots trying some different settings with an ND2 filter started with my 18/135 and then my DA 35 with an ND8 no problems other than what I induced by stopping down the lens.

All was good until I attached my HD DA 55/300 THEN THE FIRST 2 SHOTS were almost black, NO ND filter attached only a UV filter, looks like it is my HD DA 55/300 lens that is giving me grief, any suggestions?

First pic 18/135

Second pic DA 35mm

Third pic DA 55/300mm

Fourth pic DA 55/300mm

Fifth pic DA 55/300mm

Looks like my DA 55/300 is the culprit, is there a fix for this??

Link to the album where the EXIF can be reviewed:

[SharkyCA]

This problem started yesterday, I was shooting with my DA 35 2.8 macro and thought all was working fine, not reviewing each pic then I realized my pics were not exposing correctly unless I used "live view" also happening on THREE LENSES DA 35 2.8, DA 18/135mm and my DA 55/300 please see attached jpg or follow my link to the flickr post.https://www.flickr.com/gp/sharkyca/L5xqzB

[reh321]

This problem started yesterday, I was shooting with my DA 35 2.8 macro and thought all was working fine, not reviewing each pic then I realized my pics were not exposing correctly unless I used "live view" also happening on THREE LENSES DA 35 2.8, DA 18/135mm and my DA 55/300 please see attached jpg or follow my link to the flickr post.https://www.flickr.com/gp/sharkyca/L5xqzB

These are little hard to think about because you used 'Auto' mode, which means that all three exposure components vary; 'Av' or 'Tv' mode would fix two of the three components. To my eyes, these photos look like the problem reported by user @RedSky; the brighter photos do use 'brighter' exposure - wider aperture, slower shutter, higher ISO - I believe the metering used by LV mode is more accurate than the metering used by OVF mode.

[SharkyCA]

Do consider simply doing a look-see too before you head out. Even a small amount of stop-down when none is set is significant.


Steve

Hello Steve,I have followed your suggestions and have taken a few photos with my HD DA 35 checking the aperture stop down before taking shots, I did not notice ANY movement in the aperture or any dark photos. I have also used my DA 18-135 lens without any problems.

Today I took about 50 shots trying some different settings with an ND2 filter started with my 18/135 and then my DA 35 with an ND8 no problems other than what I induced by stopping down the lens.

All was good until I attached my HD DA 55/300 THEN THE FIRST 2 SHOTS were almost black, NO ND filter attached only a UV filter, looks like it is my HD DA 55/300 lens that is giving me grief, any suggestions?

First pic 18/135

Second pic DA 35mm

Third pic DA 55/300mm

Fourth pic DA 55/300mm

Fifth pic DA 55/300mm

Looks like my DA 55/300 is the culprit, is there a fix for this??

Link to the album where the EXIF can be reviewed:

These are little hard to think about because you used 'Auto' mode, which means that all three exposure components vary; 'Av' or 'Tv' mode would fix two of the three components. To my eyes, these photos look like the problem reported by user @RedSky; the brighter photos do use 'brighter' exposure - wider aperture, slower shutter, higher ISO - I believe the metering used by LV mode is more accurate than the metering used by OVF mode.

Thanks, some of the exposures were done using manual and "tav" not all in auto. If you follow my link to the Flickr images the "exif" is present.https://www.flickr.com/photos/sharkyca/sets/72157706829697591/

[stevebrot]

This problem started yesterday, I was shooting with my DA 35 2.8 macro and thought all was working fine, not reviewing each pic then I realized my pics were not exposing correctly unless I used "live view" also happening on THREE LENSES DA 35 2.8, DA 18/135mm and my DA 55/300 please see attached jpg or follow my link to the flickr post.https://www.flickr.com/gp/sharkyca/L5xqzB

These are little hard to think about because you used 'Auto' mode, which means that all three exposure components vary; 'Av' or 'Tv' mode would fix two of the three components. To my eyes, these photos look like the problem reported by user @RedSky; the brighter photos do use 'brighter' exposure - wider aperture, slower shutter, higher ISO - I believe the metering used by LV mode is more accurate than the metering used by OVF mode.

"Exposure mode - Auto" in the EXIF means exposure automation. This might include P, Av, Tv, Sv, or TAv, but never B, X, or M modes.

I have not made a full tour of the examples on Flickr, but if LV exposures are always proper, it may not be an aperture block problem. Is my memory correct that we still have no visual confirmation of aperture control failure for this camera? It may be time to put this problem out for a separate troubleshooting request.

Having said that last, I will make one comment, that being that spot metering is a common cause of exposure problems, is a specialized tool and is usually inappropriate for general shooting. I don't think it is responsible for the dark frames, but is likely a cause for the overexposed shots.


Steve

[Not a Number]

On the German Pentaxians.de forum there is poll on failures of the K-70. Of 50 respondents 4 report failure.
K-70 wer hat (keine?) Probleme mit Blendensteuerung? ? Pentaxians

One member reports buying a used K-70 that had the failure when purchased:
erste K-70 mit defekter Blendensteuerung - Black Picture ? Pentaxians

And subsequently repairing the by filing the plunger of the solenoid:
Tutorial - Reparatur Pentax K-70 Blendensteuerung Solenoid ? Pentaxians

You can use Google Translate to get an idea of what is being posted. You need to be a registered member to see many of the photographs. If you are familiar with the aperture control block mechanism on the K-30/50 and K-S1/S2 you can see the differences in design.