Is this exposure event a problem on my K70?

**psoo** · 01-31-2021, 08:04 AM

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Originally posted by psoo

I'm continuing to research my problem. However I set my exposure mode ((aperture control, time control, P) I still get a darkened first image. All subsequent shots are OK. If the solenoid is acting up I suppose a low battery voltage could be involved. I use Pentax and Nixxell batteries and they have always served me well. I'll try four AA batteries to see if this could give a higher voltage than the Pentax batteries. Who knows, maybe it will work if the four AA's give a higher voltage.

Whoops, I made a mistake. The ability to use four AA batteries is only possible for the K50. Can't do it on the K70. So I can't check to see if battery voltage is a cause of my problem.

MrB1 · 01-31-2021, 08:56 AM

Does this odd exposure effect happen every time after switching on, or only after the camera has been unused for a day or longer?

You could try exercising the aperture mechanism before you begin to take shots:- Within Camera Menu 5 - Button Customisation - set one of the Fx buttons to Optical Preview. Then you can press that Fx button a few times with different apertures (but not wide open) and see the effect in the viewfinder without actually taking a shot.

Philip

**psoo** · 01-31-2021, 09:11 AM

Originally posted by MrB1

Does this odd exposure effect happen every time after switching on, or only after the camera has been unused for a day or longer?

You could try exercising the aperture mechanism before you begin to take shots:- Within Camera Menu 5 - Button Customisation - set one of the Fx buttons to Optical Preview. Then you can press that FX button a few times with different apertures (but not wide open) and see the effect in the viewfinder without actually taking the shot.

Philip

Phil, thanks for your comment. I find that the first shot is always dark but not black. The next pics are all fine. If I switch off the camera, and immediately switch it back on, the photos are all properly exposed. However, if I wait for about 10 mins,, I get the problem again. I don't think it's a question of exercising the shutter, the shutter has been in action regularly since I use the camera often.I'm beginning to think it's an electrical problem. I wouldn't be worried if it was only the first shot that was dark, I could live forever with that problem. I just don't want the image to black out for all the photos rendering the camera unusable.

MrB1 · 01-31-2021, 09:25 AM

Originally posted by psoo

I don't think it's a question of exercising the shutter, the shutter has been in action regularly since I use the camera often.

Please note that my post was about exercising the aperture mechanism NOT the shutter.

Cheers.
Philip

**psoo** · 01-31-2021, 10:07 AM

Originally posted by MrB1

Please note that my post was about exercising the aperture mechanism NOT the shutter.

Cheers.
Philip

Hi again, Phil, I misread your comment. I guess I could exercise the aperture mechanism, they way you suggested, to get it up and running. However, it seems the first dark shot I take actually does exercise the aperture and fixes the problem, if indeed it is a sticky aperture effect.

**photogem** · 01-31-2021, 11:27 AM

You cannot use 4x AA batteries in the K70. That was K30/50/500 and K-r only (except battery-grips for K7/5/3)
Also 4 x AA's ... if one could use them, would not allow for higher voltage but higher surge-power (milli-amperes).
That has helped with the K30/50/500 "at times" but in most cases only preliminary.

It also does not matter which mode: P, Av, Tv, Tav you set: if the aperture is more open, the first shot will be dark.

Also not important which battery involved. It is just the beginning.

You just apply the test shown here
https://www.pentaxforums.com/forums/193-pentax-k-70/402049-how-detect-apertu...ax-k-70-a.html
Thats the very first thing you ought to do now!

It is easy and straight forward and then you know exactly were you are.

If it is the solenoid (which it will be for 99%) then there is only one real solution:
https://www.pentaxforums.com/forums/193-pentax-k-70/399198-tutorial-repair-p...-solenoid.html

@psoo + MrB1: Although "exercising the solenoid" does work for a short time, it has lead to further complications.
So sadly better not to recommend this method.

MrB1 · 01-31-2021, 12:11 PM

Originally posted by photogem

@psoo + MrB1: Although "exercising the solenoid" does work for a short time, it has lead to further complications. So sadly better not to recommend this method.

Please do explain.

Cheers.
Philip

**photogem** · 01-31-2021, 03:16 PM

The plunger of the solenoid is stuck. If it is "forced" to be released this can lead to misalignement of the complex mechanism.

Partly explained here:

Why you shouldn't file/sand the plunger of the green Chinasolenoid but replace it - PentaxForums.com

I did once some tests:
K-50 / K-500 Aperture Solenoid fix (DIY with pics) - Page 22 - PentaxForums.com

In general it is best to take action as soon as the symptoms show up.

**psoo** · 01-31-2021, 03:34 PM

Originally posted by photogem

You cannot use 4x AA batteries in the K70. That was K30/50/500 and K-r only (except battery-grips for K7/5/3)
Also 4 x AA's ... if one could use them, would not allow for higher voltage but higher surge-power (milli-amperes).
That has helped with the K30/50/500 "at times" but in most cases only preliminary.

It also does not matter which mode: P, Av, Tv, Tav you set: if the aperture is more open, the first shot will be dark.

Also not important which battery involved. It is just the beginning.

You just apply the test shown here
How to detect aperture-block failure/stuck solenoid on Pentax K-70 - PentaxForums.com
Thats the very first thing you ought to do now!

It is easy and straight forward and then you know exactly were you are.

If it is the solenoid (which it will be for 99%) then there is only one real solution:
Tutorial/Repair Pentax K-70 with aperture-problem: Exchange solenoid - PentaxForums.com

@psoo + MrB1: Although "exercising the solenoid" does work for a short time, it has lead to further complications.
So sadly better not to recommend this method.

Hi Photogem, as I noted above, I forgot that the K70 doesn't allow the use of AA batteries like the K50 does. I think the link you gave will allow me to fully analyze my problem. I'll check it out very soon using my DA 18-135, assuming my old brain can understand and follow the instructions. Thanks.

**psoo** · 02-03-2021, 06:24 AM

Originally posted by photogem

You cannot use 4x AA batteries in the K70. That was K30/50/500 and K-r only (except battery-grips for K7/5/3)
Also 4 x AA's ... if one could use them, would not allow for higher voltage but higher surge-power (milli-amperes).
That has helped with the K30/50/500 "at times" but in most cases only preliminary.

It also does not matter which mode: P, Av, Tv, Tav you set: if the aperture is more open, the first shot will be dark.

Also not important which battery involved. It is just the beginning.

You just apply the test shown here
How to detect aperture-block failure/stuck solenoid on Pentax K-70 - PentaxForums.com
Thats the very first thing you ought to do now!

It is easy and straight forward and then you know exactly were you are.

If it is the solenoid (which it will be for 99%) then there is only one real solution:
Tutorial/Repair Pentax K-70 with aperture-problem: Exchange solenoid - PentaxForums.com

@psoo + MrB1: Although "exercising the solenoid" does work for a short time, it has lead to further complications.
So sadly better not to recommend this method.

Hi Photogem, I finally got around to checking my K70 for the aperture block problem. Using method 1 from your link, and with my DA18-135 lens attached, the first pic was underexposed when the aperture was fully open at f/3.5. When the aperture was reset to f/22, the exposure was fine. In other tests, using random aperture and ISO settings, the first shot was nearly always darker. However, once in a while, the first shot was properly exposed indicating that the solenoid was functioning properly. I dug out an old Pentax 50mm, f/4, manual lens to try method 2 to check for aperture block. Per the instructions in your link I found the camera tested positive for aperture block. So there we are. My K70 is suffering from aperture block but so far it's not terminal. Mostly, the first shots are dark but the next umpteen shots are fine. If I switch off the camera for more that a few minutes the problem recurs.I could live with this minor glitch if nothing else changed. However, as some of you have said, it's just a matter of time before it breaks down completely. I guess I'll seek out a repair shop. Thank you all for your advice.

**psoo** · 02-03-2021, 02:46 PM

I just got off the phone with Phototonics, a camera repair shop in Topeka, Kansas, and spoke to the owner about my aperture block problem. He said he had done about 50 repairs on K30's, K50"s and K70's. He used the filing down technique rather than solenoid replacement. He could try to get a Japanese solenoid but this would take longer to repair and be more costly. He gives a 3 month warranty but nobody has returned their camera to date. He charges $120 plus $21 for mailing. I read somewhere that Precision charges $150. A similar repair job a few years ago on my K50 from the guy in California charged $100, so Phototronics is reasonable. It will take about four weeks for the work. I intend to send my K70 to him and use my K50 as a backup. I thought about getting a new camera but the K70 meets all my needs, so why change?

**photogem** · 02-04-2021, 12:00 AM

Originally posted by psoo

I just got off the phone with Phototonics, a camera repair shop in Topeka, Kansas, and spoke to the owner about my aperture block problem. He said he had done about 50 repairs on K30's, K50"s and K70's. He used the filing down technique rather than solenoid replacement. He could try to get a Japanese solenoid but this would take longer to repair and be more costly. He gives a 3 month warranty but nobody has returned their camera to date. He charges $120 plus $21 for mailing. I read somewhere that Precision charges $150. A similar repair job a few years ago on my K50 from the guy in California charged $100, so Phototronics is reasonable. It will take about four weeks for the work. I intend to send my K70 to him and use my K50 as a backup. I thought about getting a new camera but the K70 meets all my needs, so why change?

Get yourself the Japanese solenoid and send it in with the camera.
It is worth the extra costs!
This one:

Pentax K-30 K-50 K-70 K-S1/S2 K-500 Genuine White Solenoid Part - Japan - | eBay
I don't know the people behind this offer, but once purchased a solenoid from them, So I am not related,befriended, don't get percentage or anything in that direction!

**psoo** · 02-04-2021, 07:38 AM

Thanks for the advice Phoptogem. I just ordered a Japanese solenoid to fix my K70. The aperture problem I had with my K50 was fixed by the filing method and I have had no problems to date. However, spending a few extra $$ by purchasing the Japanese solenoid will give me peace of mind. Thanks.

**photogem** · 02-04-2021, 08:25 AM

Not only piece of mind (although the most important):
Quite a few people noticed that when they had installed the white DSLR Japan-Solenoid for the green one,
the K30/50 shot what one person described as snappier
I can confirm this.

gatorguy · 02-04-2021, 11:45 AM

Originally posted by photogem

Not only piece of mind (although the most important):
Quite a few people noticed that when they had installed the white DSLR Japan-Solenoid for the green one,
the K30/50 shot what one person described as snappier
I can confirm this.

Based on your suggestions I proactively purchased that white solenoid a few weeks ago from the seller you highlighted and have it put up "just in case". It wasn't at all expensive and with the detailed instruction you've graciously given us on replacing one it should be within my skill level if it's ever needed.

01-31-2021, 08:56 AM	#17
MrB1 Pentaxian Join Date: May 2013 Location: Hertfordshire, England Posts: 845	Does this odd exposure effect happen every time after switching on, or only after the camera has been unused for a day or longer? You could try exercising the aperture mechanism before you begin to take shots:- Within Camera Menu 5 - Button Customisation - set one of the Fx buttons to Optical Preview. Then you can press that Fx button a few times with different apertures (but not wide open) and see the effect in the viewfinder without actually taking a shot. Philip Last edited by MrB1; 01-31-2021 at 09:01 AM.

01-31-2021, 11:27 AM	#21
photogem Site Supporter Join Date: Apr 2015 Posts: 3,524	You cannot use 4x AA batteries in the K70. That was K30/50/500 and K-r only (except battery-grips for K7/5/3) Also 4 x AA's ... if one could use them, would not allow for higher voltage but higher surge-power (milli-amperes). That has helped with the K30/50/500 "at times" but in most cases only preliminary. It also does not matter which mode: P, Av, Tv, Tav you set: if the aperture is more open, the first shot will be dark. Also not important which battery involved. It is just the beginning. You just apply the test shown here https://www.pentaxforums.com/forums/193-pentax-k-70/402049-how-detect-apertu...ax-k-70-a.html Thats the very first thing you ought to do now! It is easy and straight forward and then you know exactly were you are. If it is the solenoid (which it will be for 99%) then there is only one real solution: https://www.pentaxforums.com/forums/193-pentax-k-70/399198-tutorial-repair-p...-solenoid.html @psoo + MrB1: Although "exercising the solenoid" does work for a short time, it has lead to further complications. So sadly better not to recommend this method. Last edited by photogem; 01-31-2021 at 11:35 AM.

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01-31-2021, 08:04 AM	#16
psoo Site Supporter Join Date: Jan 2012 Location: Long Island, NY Posts: 485 Original Poster	Staff note: This post may contain affiliate links, which means Pentax Forums may earn a small commission if a visitor clicks through and makes a purchase. If you would like to support the forum directly, you may also make a donation here. Originally posted by psoo I'm continuing to research my problem. However I set my exposure mode ((aperture control, time control, P) I still get a darkened first image. All subsequent shots are OK. If the solenoid is acting up I suppose a low battery voltage could be involved. I use Pentax and Nixxell batteries and they have always served me well. I'll try four AA batteries to see if this could give a higher voltage than the Pentax batteries. Who knows, maybe it will work if the four AA's give a higher voltage. Whoops, I made a mistake. The ability to use four AA batteries is only possible for the K50. Can't do it on the K70. So I can't check to see if battery voltage is a cause of my problem.

01-31-2021, 09:11 AM	#18
psoo Site Supporter Join Date: Jan 2012 Location: Long Island, NY Posts: 485 Original Poster	Originally posted by MrB1 Does this odd exposure effect happen every time after switching on, or only after the camera has been unused for a day or longer? You could try exercising the aperture mechanism before you begin to take shots:- Within Camera Menu 5 - Button Customisation - set one of the Fx buttons to Optical Preview. Then you can press that FX button a few times with different apertures (but not wide open) and see the effect in the viewfinder without actually taking the shot. Philip Phil, thanks for your comment. I find that the first shot is always dark but not black. The next pics are all fine. If I switch off the camera, and immediately switch it back on, the photos are all properly exposed. However, if I wait for about 10 mins,, I get the problem again. I don't think it's a question of exercising the shutter, the shutter has been in action regularly since I use the camera often.I'm beginning to think it's an electrical problem. I wouldn't be worried if it was only the first shot that was dark, I could live forever with that problem. I just don't want the image to black out for all the photos rendering the camera unusable.

01-31-2021, 09:25 AM	#19
MrB1 Pentaxian Join Date: May 2013 Location: Hertfordshire, England Posts: 845	Originally posted by psoo I don't think it's a question of exercising the shutter, the shutter has been in action regularly since I use the camera often. Please note that my post was about exercising the aperture mechanism NOT the shutter. Cheers. Philip

01-31-2021, 10:07 AM	#20
psoo Site Supporter Join Date: Jan 2012 Location: Long Island, NY Posts: 485 Original Poster	Originally posted by MrB1 Please note that my post was about exercising the aperture mechanism NOT the shutter. Cheers. Philip Hi again, Phil, I misread your comment. I guess I could exercise the aperture mechanism, they way you suggested, to get it up and running. However, it seems the first dark shot I take actually does exercise the aperture and fixes the problem, if indeed it is a sticky aperture effect.

01-31-2021, 12:11 PM	#22
MrB1 Pentaxian Join Date: May 2013 Location: Hertfordshire, England Posts: 845	Originally posted by photogem @psoo + MrB1: Although "exercising the solenoid" does work for a short time, it has lead to *further complications*. So sadly better not to recommend this method. Please do explain. Cheers. Philip

01-31-2021, 03:16 PM	#23
photogem Site Supporter Join Date: Apr 2015 Posts: 3,524	The plunger of the solenoid is stuck. If it is "forced" to be released this can lead to misalignement of the complex mechanism. Partly explained here: Why you shouldn't file/sand the plunger of the green Chinasolenoid but replace it - PentaxForums.com I did once some tests: K-50 / K-500 Aperture Solenoid fix (DIY with pics) - Page 22 - PentaxForums.com In general it is best to take action as soon as the symptoms show up.

01-31-2021, 03:34 PM	#24
psoo Site Supporter Join Date: Jan 2012 Location: Long Island, NY Posts: 485 Original Poster	Originally posted by photogem You cannot use 4x AA batteries in the K70. That was K30/50/500 and K-r only (except battery-grips for K7/5/3) Also 4 x AA's ... if one could use them, would not allow for higher voltage but higher surge-power (milli-amperes). That has helped with the K30/50/500 "at times" but in most cases only preliminary. It also does not matter which mode: P, Av, Tv, Tav you set: if the aperture is more open, the first shot will be dark. Also not important which battery involved. It is just the beginning. You just apply the test shown here How to detect aperture-block failure/stuck solenoid on Pentax K-70 - PentaxForums.com Thats the very first thing you ought to do now! It is easy and straight forward and then you know exactly were you are. If it is the solenoid (which it will be for 99%) then there is only one real solution: Tutorial/Repair Pentax K-70 with aperture-problem: Exchange solenoid - PentaxForums.com @psoo + MrB1: Although "exercising the solenoid" does work for a short time, it has lead to further complications. So sadly better not to recommend this method. Hi Photogem, as I noted above, I forgot that the K70 doesn't allow the use of AA batteries like the K50 does. I think the link you gave will allow me to fully analyze my problem. I'll check it out very soon using my DA 18-135, assuming my old brain can understand and follow the instructions. Thanks.

02-03-2021, 06:24 AM	#25
psoo Site Supporter Join Date: Jan 2012 Location: Long Island, NY Posts: 485 Original Poster	Originally posted by photogem You cannot use 4x AA batteries in the K70. That was K30/50/500 and K-r only (except battery-grips for K7/5/3) Also 4 x AA's ... if one could use them, would not allow for higher voltage but higher surge-power (milli-amperes). That has helped with the K30/50/500 "at times" but in most cases only preliminary. It also does not matter which mode: P, Av, Tv, Tav you set: if the aperture is more open, the first shot will be dark. Also not important which battery involved. It is just the beginning. You just apply the test shown here How to detect aperture-block failure/stuck solenoid on Pentax K-70 - PentaxForums.com Thats the very first thing you ought to do now! It is easy and straight forward and then you know exactly were you are. If it is the solenoid (which it will be for 99%) then there is only one real solution: Tutorial/Repair Pentax K-70 with aperture-problem: Exchange solenoid - PentaxForums.com @psoo + MrB1: Although "exercising the solenoid" does work for a short time, it has lead to further complications. So sadly better not to recommend this method. Hi Photogem, I finally got around to checking my K70 for the aperture block problem. Using method 1 from your link, and with my DA18-135 lens attached, the first pic was underexposed when the aperture was fully open at f/3.5. When the aperture was reset to f/22, the exposure was fine. In other tests, using random aperture and ISO settings, the first shot was nearly always darker. However, once in a while, the first shot was properly exposed indicating that the solenoid was functioning properly. I dug out an old Pentax 50mm, f/4, manual lens to try method 2 to check for aperture block. Per the instructions in your link I found the camera tested positive for aperture block. So there we are. My K70 is suffering from aperture block but so far it's not terminal. Mostly, the first shots are dark but the next umpteen shots are fine. If I switch off the camera for more that a few minutes the problem recurs.I could live with this minor glitch if nothing else changed. However, as some of you have said, it's just a matter of time before it breaks down completely. I guess I'll seek out a repair shop. Thank you all for your advice.

02-03-2021, 02:46 PM	#26
psoo Site Supporter Join Date: Jan 2012 Location: Long Island, NY Posts: 485 Original Poster	I just got off the phone with Phototonics, a camera repair shop in Topeka, Kansas, and spoke to the owner about my aperture block problem. He said he had done about 50 repairs on K30's, K50"s and K70's. He used the filing down technique rather than solenoid replacement. He could try to get a Japanese solenoid but this would take longer to repair and be more costly. He gives a 3 month warranty but nobody has returned their camera to date. He charges $120 plus $21 for mailing. I read somewhere that Precision charges $150. A similar repair job a few years ago on my K50 from the guy in California charged $100, so Phototronics is reasonable. It will take about four weeks for the work. I intend to send my K70 to him and use my K50 as a backup. I thought about getting a new camera but the K70 meets all my needs, so why change?

02-04-2021, 12:00 AM	#27
photogem Site Supporter Join Date: Apr 2015 Posts: 3,524	Originally posted by psoo I just got off the phone with Phototonics, a camera repair shop in Topeka, Kansas, and spoke to the owner about my aperture block problem. He said he had done about 50 repairs on K30's, K50"s and K70's. He used the filing down technique rather than solenoid replacement. He could try to get a Japanese solenoid but this would take longer to repair and be more costly. He gives a 3 month warranty but nobody has returned their camera to date. He charges $120 plus $21 for mailing. I read somewhere that Precision charges $150. A similar repair job a few years ago on my K50 from the guy in California charged $100, so Phototronics is reasonable. It will take about four weeks for the work. I intend to send my K70 to him and use my K50 as a backup. I thought about getting a new camera but the K70 meets all my needs, so why change? Get yourself the Japanese solenoid and send it in with the camera. It is worth the extra costs! This one: Pentax K-30 K-50 K-70 K-S1/S2 K-500 Genuine White Solenoid Part - Japan - \| eBay I don't know the people behind this offer, but once purchased a solenoid from them, So I am not related,befriended, don't get percentage or anything in that direction!

02-04-2021, 07:38 AM	#28
psoo Site Supporter Join Date: Jan 2012 Location: Long Island, NY Posts: 485 Original Poster	Thanks for the advice Phoptogem. I just ordered a Japanese solenoid to fix my K70. The aperture problem I had with my K50 was fixed by the filing method and I have had no problems to date. However, spending a few extra $$ by purchasing the Japanese solenoid will give me peace of mind. Thanks.

02-04-2021, 08:25 AM	#29
photogem Site Supporter Join Date: Apr 2015 Posts: 3,524	Not only piece of mind (although the most important): Quite a few people noticed that when they had installed the white DSLR Japan-Solenoid for the green one, the K30/50 shot what one person described as snappier I can confirm this.

02-04-2021, 11:45 AM	#30
gatorguy Moderator Join Date: Feb 2015 Location: Central Florida Photos: Gallery Posts: 6,094	Originally posted by photogem Not only piece of mind (although the most important): Quite a few people noticed that when they had installed the white DSLR Japan-Solenoid for the green one, the K30/50 shot what one person described as snappier I can confirm this. Based on your suggestions I proactively purchased that white solenoid a few weeks ago from the seller you highlighted and have it put up "just in case". It wasn't at all expensive and with the detailed instruction you've graciously given us on replacing one it should be within my skill level if it's ever needed.