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10-10-2018, 09:38 PM   #1
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K70 aperture block?

Does anyone know if the k-70 has the same type of aperture/solenoid mechanism as the k-50, K-30 etc-prone to failure ?

10-10-2018, 10:12 PM - 2 Likes   #2
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QuoteOriginally posted by littlemoose Quote
Does anyone know if the k-70 has the same type of aperture/solenoid mechanism as the k-50, K-30 etc-prone to failure ?
The short answer is no one has done a published tear-down of a K-70, so the mechanism used is not known. The longer answer is that the diaphragm control block design in the failure prone models (K-30, K-50, K-500, and to a much lesser extent K-S2) has been used in almost all Pentax bodies dating back to the early 1980s with a high level of reliability. The problems that originally surfaced in the K-30 were apparently due to a change in quality in solenoid assemblies sourced from an outside vendor that carried over to two successor models (K-50 and K-500) in a fairly short product release cycle. All three models have essentially identical mechanical parts with the first K-30 failures became apparent during the time when most K-50s were produced and the cause was not characterized until after the release of the K-500.

There were reports of problems with aperture control on the K-S2, but it is unclear the degree of which those where traceable to failure of the diaphragm control block. It is possible that the K-70 has a control block similar to the K-S2, but not known for certain. In recent weeks, some users have expressed concern about the K-70. Reasons for this concern is not clear. In response to those concerns, a thread on this site has been dedicated to tracking all reports and characterizing the problem and cause where possible. For the current status:

K-70 Underexposed Photo Reports - PentaxForums.com

New reports are added as they are discovered, but are limited to experiences of registered users her at Pentax Forums.


Steve

Last edited by stevebrot; 10-10-2018 at 10:33 PM. Reason: grammar and clarity
10-11-2018, 06:50 AM   #3
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The few reports that are starting to come out seem to point to the K-70 having the same aperture motor issues as the K-30/50/500 & some K-S1/S2 cameras.

I wouldn't be surprised if Ricoh is still using the faulty "green" solenoid in them. I'd be willing to bet on that.

I had thought of buying one as a backup body for the future K-3II replacement, but I'm going to skip it. I already fixed my K-50 by replacing the "green" solenoid for a "white" one. Don't need to do that again.
10-11-2018, 07:07 AM   #4
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My K-70 aperture control failed in late August. I sent it for repair to authorized service in Warsaw. Unfortunatelly it was out-of-warranty repair, ~140 USD (517 PLN).
BTW, interesting how reliable is new electronic aperture control in 55-300 PLM lens. More reliable then in-body mechanism? Time will tell.
(I have this lens, so I was able to shoot some photos even after body failure.)

10-11-2018, 09:30 AM - 1 Like   #5
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QuoteOriginally posted by The Squirrel Mafia Quote
The few reports that are starting to come out seem to point to the K-70 having the same aperture motor issues as the K-30/50/500 & some K-S1/S2 cameras.

I wouldn't be surprised if Ricoh is still using the faulty "green" solenoid in them. I'd be willing to bet on that.

I had thought of buying one as a backup body for the future K-3II replacement, but I'm going to skip it. I already fixed my K-50 by replacing the "green" solenoid for a "white" one. Don't need to do that again.
What is the basis for these claims? I am active on related threads on this site and none have been confirmed to involve the G100 diaphragm control block at this date. The further assertion of presumed bad "green" solenoid being used is entirely baseless and has potential to create false Internet rumors of intentional bad faith on the part of Ricoh/Pentax. To be more pointed, there is no hard evidence that the G100 assembly is even used on the K-70, much less the color of the parts.

Assumptions are not a valid basis for rumor or accusations.


Steve

Last edited by stevebrot; 10-11-2018 at 11:30 AM.
10-11-2018, 09:39 AM   #6
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QuoteOriginally posted by asalwa Quote
My K-70 aperture control failed in late August. I sent it for repair to authorized service in Warsaw. Unfortunatelly it was out-of-warranty repair, ~140 USD (517 PLN).
BTW, interesting how reliable is new electronic aperture control in 55-300 PLM lens. More reliable then in-body mechanism? Time will tell.
(I have this lens, so I was able to shoot some photos even after body failure.)
Thanks for chiming in. I am surprised that your camera was not under the longer warranty offered to people within the EU. That being said, the amount charged was less than what it would have cost in the U.S. Did the repair shop indicate what parts were replaced? I will add your experience to the other reports...

K-70 Underexposed Photo Reports - PentaxForums.com


Steve
10-11-2018, 11:33 AM   #7
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QuoteOriginally posted by littlemoose Quote
Does anyone know if the k-70 has the same type of aperture/solenoid mechanism as the k-50, K-30 etc-prone to failure ?
What I remember, but cannot find right now, is a report, or reports, of Pentax saying that the KP does not have that mechanism, but their not saying anything about the K-70.

There is nothing wrong with the mechanism design; Pentax used some variation for many years with no issues. The problem seems to be with the materials used by suppliers.

I prefer to talk in terms of defining symptoms, as is done with human illness, such as SIDS and AIDS {the last 'S' in each case stands for 'Syndrome', meaning they initially grouped cases together by symptoms}. We have heard of several claims of what I call 'Dark Image Syndrome' in the K-70, but it is way too early to say what causes it or about how common it is.

Last edited by reh321; 10-11-2018 at 11:39 AM.
10-11-2018, 12:10 PM   #8
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QuoteOriginally posted by reh321 Quote
We have heard of several claims of what I call 'Dark Image Syndrome' in the K-70, but it is way too early to say what causes it or about how common it is.
Indeed. It is important to note that most Pentax dSLR models have had user reports of exposure problems. Causes include:
  • User error (many ways this can happen)
  • Bad electronics (main board, meter circuit, aperture controller, etc.)
  • Water incursion
  • Mirror not moving out of the way
  • Bad/damaged lens
Pretty much every part of a camera has potential for defect in manufacturing materials, and/or design.


Steve

10-11-2018, 01:17 PM - 1 Like   #9
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QuoteOriginally posted by stevebrot Quote
Thanks for chiming in. I am surprised that your camera was not under the longer warranty offered to people within the EU. That being said, the amount charged was less than what it would have cost in the U.S. Did the repair shop indicate what parts were replaced? I will add your experience to the other reports...

Steve
I bought this camera in US. Actually failure happened in last weeks of US warranty. But shipping camera there and back would cost more than the repair in Poland. I bought more Pentax equipment this way so I can say that I saved more on price differences anyway
10-11-2018, 01:38 PM   #10
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QuoteOriginally posted by asalwa Quote
My K-70 aperture control failed in late August. I sent it for repair to authorized service in Warsaw. Unfortunatelly it was out-of-warranty repair, ~140 USD (517 PLN).
BTW, interesting how reliable is new electronic aperture control in 55-300 PLM lens. More reliable then in-body mechanism? Time will tell.
(I have this lens, so I was able to shoot some photos even after body failure.)
I have the 55-300 PLM which I bought 3 years ago. Since the PLM technology is very new, I bought an extended warranty with it. So far, no problems, the lens works perfectly. I have not heard of anyone else having unusual reliability issues with this lens
10-11-2018, 04:39 PM - 1 Like   #11
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QuoteOriginally posted by jddwoods Quote
I have the 55-300 PLM which I bought 3 years ago. Since the PLM technology is very new, I bought an extended warranty with it. So far, no problems, the lens works perfectly. I have not heard of anyone else having unusual reliability issues with this lens
The 55-300 PLM WR RE will never have aperture block failure because it doesn't use the aperture block for aperture control . . .
10-11-2018, 10:35 PM - 1 Like   #12
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I'm sure that part of the issue is reviews that someone keeps posting in the Pentax reviews at B&H. If you look at the silver K-70 reviews almost all are five star. The one single star review says nothing about the camera. It just says many Pentax cameras have this failure. A surprising/dismaying number of people found the review useful. Somebody, probably the same guy, posts the same stuff for every APS-C model. My guess is that K-50 cameras with serial number that start with 4 are way more prone to the problem. Second batch K-50 cameras and other models have failures at what would be considered a normal rate but because of the early K-50 cameras people are scared. It is very difficult to know what percentage of cameras have an issue by looking at forums etc.
10-12-2018, 12:32 AM   #13
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QuoteOriginally posted by pentaxus Quote
I'm sure that part of the issue is reviews that someone keeps posting in the Pentax reviews at B&H. If you look at the silver K-70 reviews almost all are five star. The one single star review says nothing about the camera. It just says many Pentax cameras have this failure. A surprising/dismaying number of people found the review useful. Somebody, probably the same guy, posts the same stuff for every APS-C model. My guess is that K-50 cameras with serial number that start with 4 are way more prone to the problem. Second batch K-50 cameras and other models have failures at what would be considered a normal rate but because of the early K-50 cameras people are scared. It is very difficult to know what percentage of cameras have an issue by looking at forums etc.

The reason I raised this issue is my K50 looks like it has failed at 10k shutter count- just outside of my extended warranty. I am trying to assess options etc. One option may be a K 70 which reviews imply is far better value than a KP. I have K x too but bought the K 50 for the WR, focus peak etc. repair may not last either.

For those who track these the s/n is 6082736xxx
10-12-2018, 07:29 AM   #14
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QuoteOriginally posted by The Squirrel Mafia Quote
The few reports that are starting to come out seem to point to the K-70 having the same aperture motor issues as the K-30/50/500 & some K-S1/S2 cameras.

I wouldn't be surprised if Ricoh is still using the faulty "green" solenoid in them. I'd be willing to bet on that.

I had thought of buying one as a backup body for the future K-3II replacement, but I'm going to skip it. I already fixed my K-50 by replacing the "green" solenoid for a "white" one. Don't need to do that again.
QuoteOriginally posted by stevebrot Quote
What is the basis for these claims? I am active on related threads on this site and none have been confirmed to involve the G100 diaphragm control block at this date. The further assertion of presumed bad "green" solenoid being used is entirely baseless and has potential to create false Internet rumors of intentional bad faith on the part of Ricoh/Pentax. To be more pointed, there is no hard evidence that the G100 assembly is even used on the K-70, much less the color of the parts.

Assumptions are not a valid basis for rumor or accusations.


Steve
F.U.D. at its best.

QuoteOriginally posted by reh321 Quote
What I remember, but cannot find right now, is a report, or reports, of Pentax saying that the KP does not have that mechanism, but their not saying anything about the K-70.

There is nothing wrong with the mechanism design; Pentax used some variation for many years with no issues. The problem seems to be with the materials used by suppliers.

I prefer to talk in terms of defining symptoms, as is done with human illness, such as SIDS and AIDS {the last 'S' in each case stands for 'Syndrome', meaning they initially grouped cases together by symptoms}. We have heard of several claims of what I call 'Dark Image Syndrome' in the K-70, but it is way too early to say what causes it or about how common it is.

See below:

QuoteOriginally posted by paolo11 Quote
My self and another member both called Pentax USA, and they said, no, K70 has a different mechanism.
QuoteOriginally posted by paolo11 Quote
I agree in part, but the problem it seems was carried over to the K50 and Pentax knew they had a rash of failures with the K30. So what is the failure rate between these models and other? I'm sure it's top secret.

My wife had about 1100 actuations, and a weak battery when this happen (about 1/2 power). I've been reading about the various posted fixes, and they vary, reason I mailed it out to someone smarter then me on camera repairs.

They no longer use this type of aperture control, the K70 is different as told to me by Pentax.
From the bulge on the KP next to the mirror box it has been surmised that the KP uses the same or similar motor driven G200 Diaphragm Control Block assembly as the K-7/K-5/K-3.

Last edited by Not a Number; 10-12-2018 at 08:15 AM. Reason: reorganise
10-12-2018, 08:55 AM   #15
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QuoteOriginally posted by Not a Number Quote
See below:
Nice piece of sleuthing.

QuoteOriginally posted by pentaxus Quote
I'm sure that part of the issue is reviews that someone keeps posting in the Pentax reviews at B&H.
Yes, probably in part. The review in question has been posted to K-70 listings at B&H with a negative review from the same author also posted to Adorama. There is a similar anonymous review at Amazon (the home of sketchy reviews) as well. The review at Adorama explicitly states that the reviewer owned a K-50, not a K-70. I have huge sympathy for those K-30/K-50 owners whose cameras languished on a shelf except for holidays and vacations and which showed symptoms of failure at well under 10,000 shutter cycles and, usually, long after the warranty had expired. The reported cost to fix at an authorized service place ($130-$170 USD) has been modest by camera repair standards, but sentiments on the part of many remain that Ricoh should have done a full recall of all K-30/K-50/K-500 bodies. There are some bitter owners out there.


Steve
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