One OVER and one UNDER exposed shot with the K-70

stevebrot · 09-23-2021, 10:41 AM

Originally posted by RobSpain

The basic answer to your comment is yes, they are consistent, ONCE I've got over the first UNDER exposed shot using OVF (or OVER exposed in LV) when switching the camera on (after at least an hour in off).

I guess that means the basic answer to my comment is that you are not interested in testing your camera under controlled conditions, but prefer to reference your observations from the field. Fair enough. That does not give me enough to go on, though if your problem is one of aperture control failure, available DIY or done-by-authorized-service should do the trick.

BTW...your camera does not support 5-step HDR as a direct feature, so you must mean a five step bracket. Glad to have that cleared up. Bracketing has its quirks, but I doubt those apply here.

Steve

Last edited by stevebrot; 09-23-2021 at 10:46 AM.

RobSpain · 09-24-2021, 01:36 AM

Originally posted by stevebrot

I guess that means the basic answer to my comment is that you are not interested in testing your camera under controlled conditions, but prefer to reference your observations from the field. Fair enough. That does not give me enough to go on, though if your problem is one of aperture control failure, available DIY or done-by-authorized-service should do the trick.

BTW...your camera does not support 5-step HDR as a direct feature, so you must mean a five step bracket. Glad to have that cleared up. Bracketing has its quirks, but I doubt those apply here.

Steve

Firstly, my apologies. yes I meant a 5 step bracket.

Secondly, the camera has been off since yesterday. I've just inserted a fully charged battery, switched on and taken a series of shots in AV using the OVF and LV and there were NO under or over exposed shots. I then took a shot wide open in manual, then in AV at the same aperture, which read and reflected identical speed and ISO as the manual setting. Both pictures were perfectly exposed with no extra brightness or darkness whatsoever.

This is now the third day that I have removed batteries overnight, taken shots the next morning and all exposures are bang on! Perhaps tonight I should leave the batteries in again and see if the camera reverts back to its previous habit of delivering one under and one over upon switching on in the morning. There appears to be some sort of connection (excuse the pun) between leaving batteries in or not. Leaving them in = problem. Removing batteries = problem disappears.

**OldChE** · 09-30-2021, 06:38 PM

Originally posted by RobSpain

Just started to have an unusual experience with my K-70. When switching on (after the camera has been OFF for a few hours), the very first shot using the OVF is UNDER exposed. Again, with the camera OFF for a while and using LV, the very first shot is OVER exposed. Thereafter, using either OVF or LV all shots are perfectly exposed. I was using a fully charged battery. To ensure it’s not a lens problem, I’ve repeated the above using both the 18-50mm kit lens and the Sigma 10-20mm f/3.5, with the same result. I’ve also tried this test on a daily bases for the last couple of weeks and the reoccurrence is as regular as clockwork!

The camera is 3 years old with around 30,000 shots, mostly HDR as I use the camera for real estate photography. I’ve not had any problems up to now but this started just recently. Of course I’ve read much on the subject of K-70/K-50 etc. shutter failures but I don’t think I’ve ever seen a post detailing the above abnormality of 1 under and 1 over, and thereafter everything OK.

Any thoughts?

TIA! Robert

Aperture block failure. My k50 and k70 failures had same behavior at first. Initial shot after sitting was off, then all fine. But it got worse as time went by, eventually affecting most frames. Precision Camera fixed my k70, now works great.

RobSpain · 10-02-2021, 01:22 AM

Originally posted by OldChE

Aperture block failure. My k50 and k70 failures had same behavior at first. Initial shot after sitting was off, then all fine. But it got worse as time went by, eventually affecting most frames. Precision Camera fixed my k70, now works great.

At the moment I'm getting around the problem by using the DoF preview via the RAW Fx1 button. I actuate the button half a dozen times at different apertures and then the exposures are accurate and consistent, with no 'off' first shot. I'm sure things will revert and eventually get worse, so then I'll ship it off for repair.

**photogem** · 10-02-2021, 04:07 AM

Originally posted by RobSpain

At the moment I'm getting around the problem by using the DoF preview via the RAW Fx1 button. I actuate the button half a dozen times at different apertures and then the exposures are accurate and consistent, with no 'off' first shot. I'm sure things will revert and eventually get worse, so then I'll ship it off for repair.

Not a good idea with activating DoF preview: This shocks the stuck solenoid via a rough sudden pull. Result can be misalignment of other components behind the solenoid (about 15 hours work) or having the returnspring of one of those wheels jump out (even worse):

Thats how this then looks like.

Best to send it off to London or if you dare, repair it yourself, not too difficult.

**OldChE** · 10-02-2021, 10:19 PM

Originally posted by RobSpain

At the moment I'm getting around the problem by using the DoF preview via the RAW Fx1 button. I actuate the button half a dozen times at different apertures and then the exposures are accurate and consistent, with no 'off' first shot. I'm sure things will revert and eventually get worse, so then I'll ship it off for repair.

Fiddling with it is not going to solve the problem. You might as well proceed with getting it fixed - it will get worse, and eventually pushing this button and then that button and turning yourself around 3 times will no longer work. Believe me, I've tried.

RobSpain · 10-03-2021, 02:22 AM

Originally posted by photogem

Not a good idea with activating DoF preview: This shocks the stuck solenoid via a rough sudden pull. Result can be misalignment of other components behind the solenoid (about 15 hours work) or having the returnspring of one of those wheels jump out (even worse):

Thats how this then looks like.

Best to send it off to London or if you dare, repair it yourself, not too difficult.

Thanks for this. Yes, sounds expensive!

---------- Post added 10-03-21 at 11:24 AM ----------

Originally posted by OldChE

Fiddling with it is not going to solve the problem. You might as well proceed with getting it fixed - it will get worse, and eventually pushing this button and then that button and turning yourself around 3 times will no longer work. Believe me, I've tried.

Indeed. I agree, it's not gone get better.

reh321 · 10-05-2021, 09:04 PM

Originally posted by RobSpain

Indeed. I agree, it's not gone get better.

Did you ever get around to showing us a typical dark shot?
In looking through this thread, I don’t see one.

RobSpain · 10-07-2021, 01:46 AM

Originally posted by reh321

Did you ever get around to showing us a typical dark shot?
In looking through this thread, I don’t see one.

No, I didn't, as I don't have any more credit to upload photos. Suffice to say that that 2 or 3 black shots that I have experienced were totally black. But in general, it's just the FIRST shot that is underexposed by about 2 stops.

reh321 · 10-07-2021, 05:08 AM

Originally posted by RobSpain

No, I didn't, as I don't have any more credit to upload photos. Suffice to say that that 2 or 3 black shots that I have experienced were totally black. But in general, it's just the FIRST shot that is underexposed by about 2 stops.

There is a big difference between pictures that look black and those which are truly black.
Verbal descriptions can never be sufficient - this is one of those situations when a thousand words cannot replace one picture. Without a picture, we truly are of no help to you. We could also talk and talk, but our words would be just that - words, but no meaning. Your verbal description does sound like aperture issues, but …..

RobSpain · 10-08-2021, 02:23 AM

Originally posted by reh321

There is a big difference between pictures that look black and those which are truly black.
Verbal descriptions can never be sufficient - this is one of those situations when a thousand words cannot replace one picture. Without a picture, we truly are of no help to you. We could also talk and talk, but our words would be just that - words, but no meaning. Your verbal description does sound like aperture issues, but …..

As I said, I can't upload. But you may be right about the "but...". I'm still using the camera and notwithstanding the first shot, the camera performs OK including 5-exposure bracketed shots.

reh321 · 10-08-2021, 07:42 AM - **1 Like**

Originally posted by RobSpain

As I said, I can't upload. But you may be right about the "but...". I'm still using the camera and notwithstanding the first shot, the camera performs OK including 5-exposure bracketed shots.

I took the following shot with my K-30 when it first started experiencing what I call "Dark Image Syndrome".

The camera correctly measured the light and correctly determined shutter speed and aperture, but incorrectly closed the lens down to its smallest opening.
The result was a photo squeezed into the left quarter of the histogram.
This was true on the first shot or two - everything following was completely correct.

RobSpain · 10-09-2021, 01:55 AM

Originally posted by reh321

I took the following shot with my K-30 when it first started experiencing what I call "Dark Image Syndrome".

The camera correctly measured the light and correctly determined shutter speed and aperture, but incorrectly closed the lens down to its smallest opening.
The result was a photo squeezed into the left quarter of the histogram.
This was true on the first shot or two - everything following was completely correct.

So how long was it before the camera eventually failed?

reh321 · 10-30-2021, 01:25 PM - **1 Like**

Originally posted by RobSpain

So how long was it before the camera eventually failed?

I am still using my K-30 - now with Takumar lenses where I can set the aperture at the lens.
Please excuse my preciseness with this - it is not like my Canon Rebels, which ended up in the trash because the body did completely fail.

If you are asking about the body’s ability to control the aperture - I believe that completely failed about a year after the problem first appeared.

**photogem** · 11-02-2021, 05:21 AM

Originally posted by RobSpain

No, I didn't, as I don't have any more credit to upload photos. Suffice to say that that 2 or 3 black shots that I have experienced were totally black. But in general, it's just the FIRST shot that is underexposed by about 2 stops.

That is typical and yet, if you do this simple test *YOU* know for sure:
How to detect aperture-block failure/stuck solenoid on Pentax K-70 - PentaxForums.com

The mode must be in AV-mode.

The "stops" of an underexposed photo depends of course what aperture value was chosen.
But wide open it will be dark and
fully closed it will be fine.

Plus the check in LV-Mode looking into the lens.

In LV it MUST be f4,0, so kind of half open.
If it is fully closed, then the solenoid blocks.

10-08-2021, 07:42 AM - 1 Like	#42
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,180	Originally posted by RobSpain As I said, I can't upload. But you may be right about the "but...". I'm still using the camera and notwithstanding the first shot, the camera performs OK including 5-exposure bracketed shots. I took the following shot with my K-30 when it first started experiencing what I call "Dark Image Syndrome". The camera correctly measured the light and correctly determined shutter speed and aperture, but incorrectly closed the lens down to its smallest opening. The result was a photo squeezed into the left quarter of the histogram. This was true on the first shot or two - everything following was completely correct. Last edited by reh321; 10-08-2021 at 07:56 AM.

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09-23-2021, 10:41 AM	#31
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by RobSpain The basic answer to your comment is yes, they are consistent, ONCE I've got over the first UNDER exposed shot using OVF (or OVER exposed in LV) when switching the camera on (after at least an hour in off). I guess that means the basic answer to my comment is that you are not interested in testing your camera under controlled conditions, but prefer to reference your observations from the field. Fair enough. That does not give me enough to go on, though if your problem is one of aperture control failure, available DIY or done-by-authorized-service should do the trick. BTW...your camera does not support 5-step HDR as a direct feature, so you must mean a five step bracket. Glad to have that cleared up. Bracketing has its quirks, but I doubt those apply here. Steve Last edited by stevebrot; 09-23-2021 at 10:46 AM.

09-24-2021, 01:36 AM	#32
RobSpain Pentaxian Join Date: Oct 2018 Location: Malaga province Posts: 488 Original Poster	Originally posted by stevebrot I guess that means the basic answer to my comment is that you are not interested in testing your camera under controlled conditions, but prefer to reference your observations from the field. Fair enough. That does not give me enough to go on, though if your problem is one of aperture control failure, available DIY or done-by-authorized-service should do the trick. BTW...your camera does not support 5-step HDR as a direct feature, so you must mean a five step bracket. Glad to have that cleared up. Bracketing has its quirks, but I doubt those apply here. Steve Firstly, my apologies. yes I meant a 5 step bracket. Secondly, the camera has been off since yesterday. I've just inserted a fully charged battery, switched on and taken a series of shots in AV using the OVF and LV and there were NO under or over exposed shots. I then took a shot wide open in manual, then in AV at the same aperture, which read and reflected identical speed and ISO as the manual setting. Both pictures were perfectly exposed with no extra brightness or darkness whatsoever. This is now the third day that I have removed batteries overnight, taken shots the next morning and all exposures are bang on! Perhaps tonight I should leave the batteries in again and see if the camera reverts back to its previous habit of delivering one under and one over upon switching on in the morning. There appears to be some sort of connection (excuse the pun) between leaving batteries in or not. Leaving them in = problem. Removing batteries = problem disappears.

09-30-2021, 06:38 PM	#33
OldChE Loyal Site Supporter Join Date: May 2008 Location: Chicago area Photos: Gallery \| Albums Posts: 484	Originally posted by RobSpain Just started to have an unusual experience with my K-70. When switching on (after the camera has been OFF for a few hours), the very first shot using the OVF is UNDER exposed. Again, with the camera OFF for a while and using LV, the very first shot is OVER exposed. Thereafter, using either OVF or LV all shots are perfectly exposed. I was using a fully charged battery. To ensure it’s not a lens problem, I’ve repeated the above using both the 18-50mm kit lens and the Sigma 10-20mm f/3.5, with the same result. I’ve also tried this test on a daily bases for the last couple of weeks and the reoccurrence is as regular as clockwork! The camera is 3 years old with around 30,000 shots, mostly HDR as I use the camera for real estate photography. I’ve not had any problems up to now but this started just recently. Of course I’ve read much on the subject of K-70/K-50 etc. shutter failures but I don’t think I’ve ever seen a post detailing the above abnormality of 1 under and 1 over, and thereafter everything OK. Any thoughts? TIA! Robert Aperture block failure. My k50 and k70 failures had same behavior at first. Initial shot after sitting was off, then all fine. But it got worse as time went by, eventually affecting most frames. Precision Camera fixed my k70, now works great.

10-02-2021, 01:22 AM	#34
RobSpain Pentaxian Join Date: Oct 2018 Location: Malaga province Posts: 488 Original Poster	Originally posted by OldChE Aperture block failure. My k50 and k70 failures had same behavior at first. Initial shot after sitting was off, then all fine. But it got worse as time went by, eventually affecting most frames. Precision Camera fixed my k70, now works great. At the moment I'm getting around the problem by using the DoF preview via the RAW Fx1 button. I actuate the button half a dozen times at different apertures and then the exposures are accurate and consistent, with no 'off' first shot. I'm sure things will revert and eventually get worse, so then I'll ship it off for repair.

10-02-2021, 04:07 AM	#35
photogem Site Supporter Join Date: Apr 2015 Posts: 3,520	Originally posted by RobSpain At the moment I'm getting around the problem by using the DoF preview via the RAW Fx1 button. I actuate the button half a dozen times at different apertures and then the exposures are accurate and consistent, with no 'off' first shot. I'm sure things will revert and eventually get worse, so then I'll ship it off for repair. Not a good idea with activating DoF preview: This shocks the stuck solenoid via a rough sudden pull. Result can be misalignment of other components behind the solenoid (about 15 hours work) or having the returnspring of one of those wheels jump out (even worse): Thats how this then looks like. Best to send it off to London or if you dare, repair it yourself, not too difficult.

10-02-2021, 10:19 PM	#36
OldChE Loyal Site Supporter Join Date: May 2008 Location: Chicago area Photos: Gallery \| Albums Posts: 484	Originally posted by RobSpain At the moment I'm getting around the problem by using the DoF preview via the RAW Fx1 button. I actuate the button half a dozen times at different apertures and then the exposures are accurate and consistent, with no 'off' first shot. I'm sure things will revert and eventually get worse, so then I'll ship it off for repair. Fiddling with it is not going to solve the problem. You might as well proceed with getting it fixed - it will get worse, and eventually pushing this button and then that button and turning yourself around 3 times will no longer work. Believe me, I've tried.

10-03-2021, 02:22 AM	#37
RobSpain Pentaxian Join Date: Oct 2018 Location: Malaga province Posts: 488 Original Poster	Originally posted by photogem Not a good idea with activating DoF preview: This shocks the stuck solenoid via a rough sudden pull. Result can be misalignment of other components behind the solenoid (about 15 hours work) or having the returnspring of one of those wheels jump out (even worse): Thats how this then looks like. Best to send it off to London or if you dare, repair it yourself, not too difficult. Thanks for this. Yes, sounds expensive! ---------- Post added 10-03-21 at 11:24 AM ---------- Originally posted by OldChE Fiddling with it is not going to solve the problem. You might as well proceed with getting it fixed - it will get worse, and eventually pushing this button and then that button and turning yourself around 3 times will no longer work. Believe me, I've tried. Indeed. I agree, it's not gone get better.

10-05-2021, 09:04 PM	#38
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,180	Originally posted by RobSpain Indeed. I agree, it's not gone get better. Did you ever get around to showing us a typical dark shot? In looking through this thread, I don’t see one.

10-07-2021, 01:46 AM	#39
RobSpain Pentaxian Join Date: Oct 2018 Location: Malaga province Posts: 488 Original Poster	Originally posted by reh321 Did you ever get around to showing us a typical dark shot? In looking through this thread, I don’t see one. No, I didn't, as I don't have any more credit to upload photos. Suffice to say that that 2 or 3 black shots that I have experienced were totally black. But in general, it's just the FIRST shot that is underexposed by about 2 stops.

10-07-2021, 05:08 AM	#40
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,180	Originally posted by RobSpain No, I didn't, as I don't have any more credit to upload photos. Suffice to say that that 2 or 3 black shots that I have experienced were totally black. But in general, it's just the FIRST shot that is underexposed by about 2 stops. There is a big difference between pictures that look black and those which are truly black. Verbal descriptions can never be sufficient - this is one of those situations when a thousand words cannot replace one picture. Without a picture, we truly are of no help to you. We could also talk and talk, but our words would be just that - words, but no meaning. Your verbal description does sound like aperture issues, but …..

10-08-2021, 02:23 AM	#41
RobSpain Pentaxian Join Date: Oct 2018 Location: Malaga province Posts: 488 Original Poster	Originally posted by reh321 There is a big difference between pictures that look black and those which are truly black. Verbal descriptions can never be sufficient - this is one of those situations when a thousand words cannot replace one picture. Without a picture, we truly are of no help to you. We could also talk and talk, but our words would be just that - words, but no meaning. Your verbal description does sound like aperture issues, but ….. As I said, I can't upload. But you may be right about the "but...". I'm still using the camera and notwithstanding the first shot, the camera performs OK including 5-exposure bracketed shots.

10-09-2021, 01:55 AM	#43
RobSpain Pentaxian Join Date: Oct 2018 Location: Malaga province Posts: 488 Original Poster	Originally posted by reh321 I took the following shot with my K-30 when it first started experiencing what I call "Dark Image Syndrome". The camera correctly measured the light and correctly determined shutter speed and aperture, but incorrectly closed the lens down to its smallest opening. The result was a photo squeezed into the left quarter of the histogram. This was true on the first shot or two - everything following was completely correct. So how long was it before the camera eventually failed?

10-30-2021, 01:25 PM - 1 Like	#44
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,180	Originally posted by RobSpain So how long was it before the camera eventually failed? I am still using my K-30 - now with Takumar lenses where I can set the aperture at the lens. Please excuse my preciseness with this - it is not like my Canon Rebels, which ended up in the trash because the body did completely fail. If you are asking about the body’s ability to control the aperture - I believe that completely failed about a year after the problem first appeared.

11-02-2021, 05:21 AM	#45
photogem Site Supporter Join Date: Apr 2015 Posts: 3,520	Originally posted by RobSpain No, I didn't, as I don't have any more credit to upload photos. Suffice to say that that 2 or 3 black shots that I have experienced were totally black. But in general, it's just the FIRST shot that is underexposed by about 2 stops. That is typical and yet, if you do this simple test YOU know for sure: How to detect aperture-block failure/stuck solenoid on Pentax K-70 - PentaxForums.com The mode must be in AV-mode. The "stops" of an underexposed photo depends of course what aperture value was chosen. But wide open it will be dark and fully closed it will be fine. Plus the check in LV-Mode looking into the lens. In LV it MUST be f4,0, so kind of half open. If it is fully closed, then the solenoid blocks.