How common is the aperture block failure, really?

reh321 · 06-21-2018, 09:21 AM

Originally posted by iheiramo

I've taken one shot on purpose with DA18-135 and K30 after ABF to test how it works and if I could use it to shoot against the sun. It didn't work quite as well as I hoped.

Is this a JPEG created by the camera??

**kernos** · 06-21-2018, 09:36 AM

Originally posted by reh321

How long ago was the warranty repair? There is evidence that the aperture control units used by Pentax in to "repair" have the same kind of solenoid as is in the original unit, so they are just as likely to fail.

The repair came back 2/28/2016. It was there for months awaiting parts.

**iheiramo** · 06-21-2018, 10:07 AM

Originally posted by reh321

Is this a JPEG created by the camera??

No. DNG developed in Zoner photo studio, if I rmember correctly. I was switching to C1 about that time, so not really sure. Had to leave it a bit dark due to flare and PF.

reh321 · 06-24-2018, 04:50 AM

Originally posted by reh321

What happens if I try to use modern lenses at f/22 only?

I know that diffraction would be a factor, but how much?

Has anyone looked at DNG files? Is there actually something there if I process them enough??

For anyone "keeping score at home", as the broadcasters say.... My wife and I went on an outing yesterday. The K-30 performed flawlessly {mostly using the Sigma lens} after I exercised the aperture mechanism "until it worked" the night before, so this is still hypothetical thinking on my part.

LensBeginner · 06-24-2018, 12:40 PM

Originally posted by reh321

For anyone "keeping score at home", as the broadcasters say.... My wife and I went on an outing yesterday. The K-30 performed flawlessly {mostly using the Sigma lens} after I exercised the aperture mechanism "until it worked" the night before, so this is still hypothetical thinking on my part.

Glad yo're still getting use out of it in spite of the failure

reh321 · 06-24-2018, 04:11 PM

Originally posted by LensBeginner

Glad yo're still getting use out of it in spite of the failure

Thank you. I tried another this afternoon and it worked right first time. I may have to do something everyday to keep it working correctly.

**bhbrake** · 06-24-2018, 07:40 PM

Mine is the opposite. It exposes a few images properly, and then after I start stopping down the aperture, it freaks out and over exposes images like crazy and I have to use full manual mode or adjust eh EV or shutter manually to correct the exposures. If it was not my backup, I would have sent it in for repair by now.

reh321 · 06-24-2018, 07:48 PM

Originally posted by bhbrake

Mine is the opposite. It exposes a few images properly, and then after I start stopping down the aperture, it freaks out and over exposes images like crazy and I have to use full manual mode or adjust eh EV or shutter manually to correct the exposures. If it was not my backup, I would have sent it in for repair by now.

When you use "full manual", how are you adjusting the aperture?
(1) on the lens via aperture ring
(2) from the body using rear e-dial

**bhbrake** · 06-24-2018, 08:17 PM

Originally posted by reh321

When you use "full manual", how are you adjusting the aperture?
(1) on the lens via aperture ring
(2) from the body using rear e-dial

I don't have an aperture ring on most of my lenses, so I use the e-dial. This does of course mean the aperture block has not completely failed as there is still an ability to control it electronically, but it doesn't communicate properly with the shutter release. If I shoot in shutter priority it selects the wrong aperture, and aperture priority selects the wrong shutter speed, so I have to end up setting the S, A,and ISO all manually to get a correct exposure.

reh321 · 06-26-2018, 10:08 AM

Originally posted by reh321

Thank you. I tried another this afternoon and it worked right first time. I may have to do something everyday to keep it working correctly.

Pattern continued today - one dark one, followed by roughly a dozen good ones.

reh321 · 06-26-2018, 10:14 AM

Originally posted by bhbrake

I don't have an aperture ring on most of my lenses, so I use the e-dial. This does of course mean the aperture block has not completely failed as there is still an ability to control it electronically, but it doesn't communicate properly with the shutter release. If I shoot in shutter priority it selects the wrong aperture, and aperture priority selects the wrong shutter speed, so I have to end up setting the S, A,and ISO all manually to get a correct exposure.

Someone with more experience than me with this issue may need to respond. This doesn't sound like usual "aperture control issue", which consists only of camera body's inability to implement proper f-stop .... resulting in lens's going to smallest possible opening.

Klaus · 06-26-2018, 12:01 PM

I had such a problem long time ago, with my K10D, until I was repaired under warrantee. Camera had lost control of the aperture. They exchanged not the motherboard, but a smaller, subordinated one. Not sur what is the correct name of that part. It seems it may happen not only with certain models.

Cheers - Klaus

SSGGeezer · 06-26-2018, 12:33 PM

Originally posted by bhbrake

I don't have an aperture ring on most of my lenses, so I use the e-dial. This does of course mean the aperture block has not completely failed as there is still an ability to control it electronically, but it doesn't communicate properly with the shutter release. If I shoot in shutter priority it selects the wrong aperture, and aperture priority selects the wrong shutter speed, so I have to end up setting the S, A,and ISO all manually to get a correct exposure.

have you cleaned your lens and mount contacts and made sure they are not gunked up? Your intermittent issues sound like they could have other causes. Stevebrot is the forum member who is best at diagnosis via forum chat so i would PM him.

gatorguy · 06-26-2018, 04:01 PM

For those still wondering about more recent models I've not had this issue with either of two KS-2's or the K-70 with a few thousand shots each.. Here's hoping the chain stopped with the K-50.

**clackers** · 06-26-2018, 04:33 PM

Originally posted by gatorguy

For those still wondering about more recent models I've not had this issue with either of two KS-2's or the K-70 with a few thousand shots each.. Here's hoping the chain stopped with the K-50.

It's certainly been reported with the K-S2, Gatorguy.

The issue seems to be that solenoid used in the low end models. It can be not up to spec.

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06-21-2018, 09:21 AM	#76
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,175	Originally posted by iheiramo I've taken one shot on purpose with DA18-135 and K30 after ABF to test how it works and if I could use it to shoot against the sun. It didn't work quite as well as I hoped. Is this a JPEG created by the camera??

06-21-2018, 09:36 AM	#77
kernos Site Supporter Join Date: Feb 2013 Posts: 456	Originally posted by reh321 How long ago was the warranty repair? There is evidence that the aperture control units used by Pentax in to "repair" have the same kind of solenoid as is in the original unit, so they are just as likely to fail. The repair came back 2/28/2016. It was there for months awaiting parts.

06-21-2018, 10:07 AM	#78
iheiramo Unoriginal Poster Join Date: Nov 2016 Location: Espoo Photos: Albums Posts: 3,180	Originally posted by reh321 Is this a JPEG created by the camera?? No. DNG developed in Zoner photo studio, if I rmember correctly. I was switching to C1 about that time, so not really sure. Had to leave it a bit dark due to flare and PF.

06-24-2018, 04:50 AM	#79
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,175	Originally posted by reh321 What happens if I try to use modern lenses at f/22 only? I know that diffraction would be a factor, but how much? Has anyone looked at DNG files? Is there actually something there if I process them enough?? For anyone "keeping score at home", as the broadcasters say.... My wife and I went on an outing yesterday. The K-30 performed flawlessly {mostly using the Sigma lens} after I exercised the aperture mechanism "until it worked" the night before, so this is still hypothetical thinking on my part.

06-24-2018, 12:40 PM	#80
LensBeginner Veteran Member Join Date: Sep 2014 Photos: Albums Posts: 4,696	Originally posted by reh321 For anyone "keeping score at home", as the broadcasters say.... My wife and I went on an outing yesterday. The K-30 performed flawlessly {mostly using the Sigma lens} after I exercised the aperture mechanism "until it worked" the night before, so this is still hypothetical thinking on my part. Glad yo're still getting use out of it in spite of the failure

06-24-2018, 04:11 PM	#81
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,175	Originally posted by LensBeginner Glad yo're still getting use out of it in spite of the failure Thank you. I tried another this afternoon and it worked right first time. I may have to do something everyday to keep it working correctly.

06-24-2018, 07:40 PM	#82
bhbrake Site Supporter Join Date: Aug 2016 Location: Colorado Photos: Albums Posts: 331	Mine is the opposite. It exposes a few images properly, and then after I start stopping down the aperture, it freaks out and over exposes images like crazy and I have to use full manual mode or adjust eh EV or shutter manually to correct the exposures. If it was not my backup, I would have sent it in for repair by now.

06-24-2018, 07:48 PM	#83
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,175	Originally posted by bhbrake Mine is the opposite. It exposes a few images properly, and then after I start stopping down the aperture, it freaks out and over exposes images like crazy and I have to use full manual mode or adjust eh EV or shutter manually to correct the exposures. If it was not my backup, I would have sent it in for repair by now. When you use "full manual", how are you adjusting the aperture? (1) on the lens via aperture ring (2) from the body using rear e-dial

06-24-2018, 08:17 PM	#84
bhbrake Site Supporter Join Date: Aug 2016 Location: Colorado Photos: Albums Posts: 331	Originally posted by reh321 When you use "full manual", how are you adjusting the aperture? (1) on the lens via aperture ring (2) from the body using rear e-dial I don't have an aperture ring on most of my lenses, so I use the e-dial. This does of course mean the aperture block has not completely failed as there is still an ability to control it electronically, but it doesn't communicate properly with the shutter release. If I shoot in shutter priority it selects the wrong aperture, and aperture priority selects the wrong shutter speed, so I have to end up setting the S, A,and ISO all manually to get a correct exposure.

06-26-2018, 10:08 AM	#85
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,175	Originally posted by reh321 Thank you. I tried another this afternoon and it worked right first time. I may have to do something everyday to keep it working correctly. Pattern continued today - one dark one, followed by roughly a dozen good ones.

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06-26-2018, 10:14 AM	#86
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,175	Originally posted by bhbrake I don't have an aperture ring on most of my lenses, so I use the e-dial. This does of course mean the aperture block has not completely failed as there is still an ability to control it electronically, but it doesn't communicate properly with the shutter release. If I shoot in shutter priority it selects the wrong aperture, and aperture priority selects the wrong shutter speed, so I have to end up setting the S, A,and ISO all manually to get a correct exposure. Someone with more experience than me with this issue may need to respond. This doesn't sound like usual "aperture control issue", which consists only of camera body's inability to implement proper f-stop .... resulting in lens's going to smallest possible opening.

06-26-2018, 12:01 PM	#87
Klaus Senior Member Join Date: Jan 2010 Location: Murcia, Spain Photos: Gallery Posts: 100	I had such a problem long time ago, with my K10D, until I was repaired under warrantee. Camera had lost control of the aperture. They exchanged not the motherboard, but a smaller, subordinated one. Not sur what is the correct name of that part. It seems it may happen not only with certain models. Cheers - Klaus

06-26-2018, 12:33 PM	#88
SSGGeezer Veteran Member Join Date: Jun 2017 Location: Indiana, U.S. Photos: Gallery \| Albums Posts: 4,845	Originally posted by bhbrake I don't have an aperture ring on most of my lenses, so I use the e-dial. This does of course mean the aperture block has not completely failed as there is still an ability to control it electronically, but it doesn't communicate properly with the shutter release. If I shoot in shutter priority it selects the wrong aperture, and aperture priority selects the wrong shutter speed, so I have to end up setting the S, A,and ISO all manually to get a correct exposure. have you cleaned your lens and mount contacts and made sure they are not gunked up? Your intermittent issues sound like they could have other causes. Stevebrot is the forum member who is best at diagnosis via forum chat so i would PM him.

06-26-2018, 04:01 PM	#89
gatorguy Moderator Join Date: Feb 2015 Location: Central Florida Photos: Gallery Posts: 6,089	For those still wondering about more recent models I've not had this issue with either of two KS-2's or the K-70 with a few thousand shots each.. Here's hoping the chain stopped with the K-50.

06-26-2018, 04:33 PM	#90
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by gatorguy For those still wondering about more recent models I've not had this issue with either of two KS-2's or the K-70 with a few thousand shots each.. Here's hoping the chain stopped with the K-50. It's certainly been reported with the K-S2, Gatorguy. The issue seems to be that solenoid used in the low end models. It can be not up to spec.