K50 Under Exposure in View Finder Mode

Gary Whitfield · 08-12-2019, 11:53 AM

I just added a Ricoh Pentax 55 - 300 mm lense. Went out on the lake to shoot the loones. All pictures are almost black, under exposed.
I have tried changing several settings. The only thing that has worked is to shoot in live view mode. This is the same for all of my lenses. I alway shoot in auto setting and sometimes manual focus.
Any suggestions.

**erikro** · 08-12-2019, 11:59 AM

It is a common fault in k-30 and k-50, bad solinoid controling apeturelevel.
There is a lot of descriptions in the forum.
It is easy to repair if you can do it yourself and have an old Pentax camera you can take the solinoid from.
Erik

The Squirrel Mafia · 08-12-2019, 12:00 PM

Hmmm... That is weird. Sounds like the dreaded aperture motor issue, but then you say that it works perfectly fine in live view. Could be something else.

Pentax K-30 & K-50 - PentaxForums.com

^ Visit this section & take a look at the threads. You might find one that will give you an idea.

**mikesbike** · 08-12-2019, 03:42 PM

You say you just added a 55-300mm lens- do you get this underexposure now with your other lens(es)?

JohnX · 08-13-2019, 03:23 AM

Which 55-300?

Gary Whitfield · 08-13-2019, 12:17 PM

Originally posted by mikesbike

You say you just added a 55-300mm lens- do you get this underexposure now with your other lens(es)?

Yes the problem is consistent with all 3 of my lenses. It must be coinsidental that it started with new lense.

Gary Whitfield · 08-13-2019, 12:26 PM

Originally posted by JohnX

Which 55-300?

Ricoh HD Pentax DA 55-300
f4.5 -6.3 ED PLM WR RE From Adorama.

**ehrwien** · 08-13-2019, 12:34 PM

Originally posted by Gary Whitfield

Ricoh HD Pentax DA 55-300
f4.5 -6.3 ED PLM WR RE From Adorama.

Did you update your firmware to the latest version prior to using this lens?

The Squirrel Mafia · 08-13-2019, 12:35 PM

Ah! Maybe you need the latest V1.10 firmware update to get it to work, since that lens is a newer KAF4 design.

Latest K-50 Firmware Update : Software Downloads | RICOH IMAGING

^ Go there.

Auzzie-Phoenix · 08-13-2019, 11:04 PM

But they said it was consistent with all 3 of their lenses, so the firmware revision wouldn't matter. I can think of 2 potential problems... the light/exposure sensor in the bottom of the sensor box, or the aperature solenoid. If your other 2 lenses have aperature rings, set the camera up to use aperature ring operation, and test exposures by using manual aperture. If doing so results in proper images, try a lens without manual aperature operation and see if problem resumes. If so, then it's aperature failure. If manual aperature does not solve the issue, then light sensor is suspect.

**ehrwien** · 08-14-2019, 02:38 AM

Even if it should be a faulty solenoid, after updating the firmware the PLM should work correctly.

**mikesbike** · 08-14-2019, 09:35 AM

Originally posted by ehrwien

Even if it should be a faulty solenoid, after updating the firmware the PLM should work correctly.

If this is true and the PLM lens will expose correctly, this should prove the camera has the well-known solenoid aperture failure. The fact it began after the new lens arrived is simply coincidence.

Gary Whitfield · 08-14-2019, 10:46 AM

Originally posted by The Squirrel Mafia

Ah! Maybe you need the latest V1.10 firmware update to get it to work, since that lens is a newer KAF4 design.

Latest K-50 Firmware Update : Software Downloads | RICOH IMAGING

^ Go there.

I just finished the firmware update.
No change. Works in live view does not work in view finder mode.
Now the question is, Do I trash it and upgrade or send it in for service?

---------- Post added 08-14-19 at 11:17 AM ----------

Originally posted by Auzzie-Phoenix

But they said it was consistent with all 3 of their lenses, so the firmware revision wouldn't matter. I can think of 2 potential problems... the light/exposure sensor in the bottom of the sensor box, or the aperature solenoid. If your other 2 lenses have aperature rings, set the camera up to use aperature ring operation, and test exposures by using manual aperture. If doing so results in proper images, try a lens without manual aperature operation and see if problem resumes. If so, then it's aperature failure. If manual aperature does not solve the issue, then light sensor is suspect.

No apature rings on any of the 3 lenses. Tried an old lens from my 35mm but could not get a shutter response. Probably don't know what I'm doing.

stevebrot · 08-14-2019, 12:54 PM

Welcome to the Pentax Forums!

Originally posted by Gary Whitfield

Works in live view does not work in view finder mode.

Herein is the detail that matters and which indicates a probable metering problem when using the optical viewfinder. My suggestion is to do a simple test:

Camera on tripod or other stationary surface so as to keep framing consistent
Av mode (suggest f/5.6)
Matrix metering
Fixed ISO (suggest 400)
Exposure Compensation set to 0
No filters
Using the optical viewfinder, do an exposure of an evenly-lit white wall. Take care that the wall fills the frame and is evenly-lit throughout with no shadows or obvious bright spots. (It may help to switch to manual focus.)
Repeat using Live View without change to any of the settings or camera position or focal length or focus

The shutter speeds for the two exposures should be the same or very close to the same, indicating both metering systems measured similar light from the wall. Live View metering is considered to be the more reliable of the two.

Steve

**ehrwien** · 08-15-2019, 02:20 AM

If the test that @stevebrot posted above (try another run metering through the viewfinder, but block the viewfinder itself with something so that no light can get in there) still turns out with the same result:

Some dust could be on the metering sensor (which sits in the pentaprism housing?!). I don't know how easy it is to get there with a rocket blower, but you could try it. Mirror not in lock-up mode and gently squeeze some wind to the top.

08-12-2019, 11:53 AM	#1
Gary Whitfield New Member Join Date: Aug 2019 Posts: 7	K50 Under Exposure in View Finder Mode I just added a Ricoh Pentax 55 - 300 mm lense. Went out on the lake to shoot the loones. All pictures are almost black, under exposed. I have tried changing several settings. The only thing that has worked is to shoot in live view mode. This is the same for all of my lenses. I alway shoot in auto setting and sometimes manual focus. Any suggestions.

08-14-2019, 12:54 PM	#14
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Welcome to the Pentax Forums! Originally posted by Gary Whitfield Works in live view does not work in view finder mode. Herein is the detail that matters and which indicates a probable metering problem when using the optical viewfinder. My suggestion is to do a simple test: Camera on tripod or other stationary surface so as to keep framing consistent Av mode (suggest f/5.6) Matrix metering Fixed ISO (suggest 400) Exposure Compensation set to 0 No filters Using the optical viewfinder, do an exposure of an evenly-lit white wall. Take care that the wall fills the frame and is evenly-lit throughout with no shadows or obvious bright spots. (It may help to switch to manual focus.) Repeat using Live View without change to any of the settings or camera position or focal length or focus The shutter speeds for the two exposures should be the same or very close to the same, indicating both metering systems measured similar light from the wall. Live View metering is considered to be the more reliable of the two. Steve

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08-12-2019, 11:59 AM	#2
erikro Site Supporter Join Date: May 2008 Location: Ølgod, Denmark Photos: Gallery Posts: 135	It is a common fault in k-30 and k-50, bad solinoid controling apeturelevel. There is a lot of descriptions in the forum. It is easy to repair if you can do it yourself and have an old Pentax camera you can take the solinoid from. Erik

08-12-2019, 12:00 PM	#3
The Squirrel Mafia Pentaxian Join Date: Jan 2015 Posts: 3,058	Hmmm... That is weird. Sounds like the dreaded aperture motor issue, but then you say that it works perfectly fine in live view. Could be something else. Pentax K-30 & K-50 - PentaxForums.com ^ Visit this section & take a look at the threads. You might find one that will give you an idea.

08-12-2019, 03:42 PM	#4
mikesbike Site Supporter Join Date: Dec 2016 Location: Southeastern Michigan Posts: 4,562	You say you just added a 55-300mm lens- do you get this underexposure now with your other lens(es)?

08-13-2019, 03:23 AM	#5
JohnX Pentaxian Join Date: Jul 2009 Location: London Posts: 1,116	Which 55-300?

08-13-2019, 12:17 PM	#6
Gary Whitfield New Member Join Date: Aug 2019 Posts: 7 Original Poster	Originally posted by mikesbike You say you just added a 55-300mm lens- do you get this underexposure now with your other lens(es)? Yes the problem is consistent with all 3 of my lenses. It must be coinsidental that it started with new lense.

08-13-2019, 12:26 PM	#7
Gary Whitfield New Member Join Date: Aug 2019 Posts: 7 Original Poster	Originally posted by JohnX Which 55-300? Ricoh HD Pentax DA 55-300 f4.5 -6.3 ED PLM WR RE From Adorama.

08-13-2019, 12:34 PM	#8
ehrwien Site Supporter Join Date: May 2016 Posts: 2,784	Originally posted by Gary Whitfield Ricoh HD Pentax DA 55-300 f4.5 -6.3 ED PLM WR RE From Adorama. Did you update your firmware to the latest version prior to using this lens?

08-13-2019, 12:35 PM	#9
The Squirrel Mafia Pentaxian Join Date: Jan 2015 Posts: 3,058	Ah! Maybe you need the latest V1.10 firmware update to get it to work, since that lens is a newer KAF4 design. Latest K-50 Firmware Update : Software Downloads \| RICOH IMAGING ^ Go there.

08-13-2019, 11:04 PM	#10
Auzzie-Phoenix Veteran Member Join Date: Sep 2014 Photos: Albums Posts: 1,020	But they said it was consistent with all 3 of their lenses, so the firmware revision wouldn't matter. I can think of 2 potential problems... the light/exposure sensor in the bottom of the sensor box, or the aperature solenoid. If your other 2 lenses have aperature rings, set the camera up to use aperature ring operation, and test exposures by using manual aperture. If doing so results in proper images, try a lens without manual aperature operation and see if problem resumes. If so, then it's aperature failure. If manual aperature does not solve the issue, then light sensor is suspect.

08-14-2019, 02:38 AM	#11
ehrwien Site Supporter Join Date: May 2016 Posts: 2,784	Even if it should be a faulty solenoid, after updating the firmware the PLM should work correctly.

08-14-2019, 09:35 AM	#12
mikesbike Site Supporter Join Date: Dec 2016 Location: Southeastern Michigan Posts: 4,562	Originally posted by ehrwien Even if it should be a faulty solenoid, after updating the firmware the PLM should work correctly. If this is true and the PLM lens will expose correctly, this should prove the camera has the well-known solenoid aperture failure. The fact it began after the new lens arrived is simply coincidence.

08-14-2019, 10:46 AM	#13
Gary Whitfield New Member Join Date: Aug 2019 Posts: 7 Original Poster	Originally posted by The Squirrel Mafia Ah! Maybe you need the latest V1.10 firmware update to get it to work, since that lens is a newer KAF4 design. Latest K-50 Firmware Update : Software Downloads \| RICOH IMAGING ^ Go there. I just finished the firmware update. No change. Works in live view does not work in view finder mode. Now the question is, Do I trash it and upgrade or send it in for service? ---------- Post added 08-14-19 at 11:17 AM ---------- Originally posted by Auzzie-Phoenix But they said it was consistent with all 3 of their lenses, so the firmware revision wouldn't matter. I can think of 2 potential problems... the light/exposure sensor in the bottom of the sensor box, or the aperature solenoid. If your other 2 lenses have aperature rings, set the camera up to use aperature ring operation, and test exposures by using manual aperture. If doing so results in proper images, try a lens without manual aperature operation and see if problem resumes. If so, then it's aperature failure. If manual aperature does not solve the issue, then light sensor is suspect. No apature rings on any of the 3 lenses. Tried an old lens from my 35mm but could not get a shutter response. Probably don't know what I'm doing.

08-15-2019, 02:20 AM	#15
ehrwien Site Supporter Join Date: May 2016 Posts: 2,784	If the test that @stevebrot posted above (try another run metering through the viewfinder, but block the viewfinder itself with something so that no light can get in there) still turns out with the same result: Some dust could be on the metering sensor (which sits in the pentaprism housing?!). I don't know how easy it is to get there with a rocket blower, but you could try it. Mirror not in lock-up mode and gently squeeze some wind to the top.