"all-dark" photos with K-50 viewfinder

detour · 07-11-2020, 12:11 AM

Hey...It was around 2:30 pm, sunny day.
I started shooting with my K-50 and found almost all-dark photos output through the viewfinder while it was all fine through the LV mode.
I tried different lens and things happened again.

through LV [auto]:

through viewfinder [auto]:

through viewfinder [Av]:

BTW It worked well using [M] mode through viewfinder:

All tests above used matrix metering. Any suggestion is welcome!

Last edited by Adam; 07-11-2020 at 02:13 AM. Reason: fixed embeds

slartibartfast01 · 07-11-2020, 12:33 AM

Originally posted by detour

Hey...It was around 2:30 pm, sunny day.

I started shooting with my K-50 and found almost all-dark photos output through the viewfinder while it was all fine through the LV mode.

I tried different lens and things happened again.

through LV [auto]:

through viewfinder [auto]:

through viewfinder [Av]:

BTW It worked well using [M] mode through viewfinder:

All tests above used matrix metering. Any suggestion is welcome!

Light entering the viewfinder can cause metering issues. Try covering the viewfinder.

Auzzie-Phoenix · 07-11-2020, 12:40 AM

That's some weird firmware display for a K-50. That aside, your problem might be aperture block related. It could also be the exposure sensor at the bottom of the mirror box housing. The lens you were using... did it have an aperture ring, or was it fully automatic, or a PLM lens? If it had an aperture ring, then it would make sense for the exposure to be fine using manual mode if the lens isn't set to Auto or A. If it's something like the 18-55 kit lens, then all images would have been dark with aperture block issue unless the aperture solenoid temporarily worked after several shots.

More testing should be done, especially after the camera has been sitting for a while.

here's a link to the aperture block thread: Dark exposure problems on K-30 or K-50? Read me first! - PentaxForums.com

**photogem** · 07-11-2020, 03:50 AM

Originally posted by detour

I started shooting with my K-50 and found almost all-dark photos output through the viewfinder while it was all fine through the LV mode.
I tried different lens and things happened again.

Very typical symptoms for aperture-block-failure, also called dark-image-syndrome

The solenoid of the diaphragm-control-block is stuck!

In LV the solenoid actuates twice but it is stuck the first actuation.

Because the solenoid actuates twice and the mirror goes down this releases energy, the solenoid gets those extra milli-amperes which brings it to release when actuating this second time.
This is why in LV it still works, even if metering is not acurate. But after a while it fails as well in LV!

Originally posted by detour

BTW It worked well using [M] mode through viewfinder

Because the solenoid is not in action in M-Mode!

You can do those tests:
Detection of aperture block/diaphragm-block failure/stuck solenoid K-30, K-50, K500 - PentaxForums.com
(well, actually you did them already kind of)

and then apply:
Manual solenoid replacement Pentax K30 / Discharge flash-condenser / Solenoid choice - PentaxForums.com

Last edited by photogem; 07-11-2020 at 03:57 AM.

**microlight** · 07-11-2020, 03:58 AM

From your photos, there's around a four-stop difference in exposure between the LV and viewfinder shots (AV) - shutter speed 1/6 rather than 1/125 - which is possibly why the auto and AV viewfinder shots look dark. Same exposure in viewfinder manual as in LV (1/6 second) which is why that one looks ok. We'd need to know exactly which lenses you were using to try to help further, I think.

**photogem** · 07-12-2020, 06:11 AM

He tried different lenses and had the same problem there.
Symptoms are so typical and 99% likelyhood failure of the solenoid.

slartibartfast01 · 07-12-2020, 06:15 AM

Originally posted by photogem

He tried different lenses and had the same problem there.
Symptoms are so typical and 99% likelyhood failure of the solenoid.

The metering is different though. He seems to have the camera on a tripod so light could be entering the viewfinder.

**photogem** · 07-12-2020, 06:34 AM

I can't see a tripod?

slartibartfast01 · 07-12-2020, 06:38 AM

Originally posted by photogem

I can't see a tripod?

Hmm you could be right but the metering is definitely different. If it was aperture block wouldn't the metering be the same?

**photogem** · 07-12-2020, 10:27 AM

I think we have to wait what our new member comes up with.
Problem is, that some ask a question, members answer (or pretend to answer) but then there is zero reply, such as with this one:
DA 50mm 1.8 aperture stuck after drop - PentaxForums.com

**microlight** · 07-12-2020, 10:56 AM - **1 Like**

That's a little rude; we're only looking for clarity.

**photogem** · 07-12-2020, 09:40 PM

Originally posted by microlight

That's a little rude; we're only looking for clarity.

What / which part is a little rude?

**microlight** · 07-12-2020, 11:30 PM

'...answer (or pretend to answer)'

**photogem** · 07-13-2020, 04:07 AM

Originally posted by microlight

'...answer (or pretend to answer)'

That wasn't coined to anybody here but just in general.
Everybody here tried just to help

**microlight** · 07-13-2020, 09:06 AM

Okay.

07-11-2020, 12:11 AM	#1
detour Senior Member Join Date: Jun 2020 Location: Guangdong Posts: 182	"all-dark" photos with K-50 viewfinder Hey...It was around 2:30 pm, sunny day. I started shooting with my K-50 and found almost all-dark photos output through the viewfinder while it was all fine through the LV mode. I tried different lens and things happened again. through LV [auto]: through viewfinder [auto]: through viewfinder [Av]: BTW It worked well using [M] mode through viewfinder: All tests above used matrix metering. Any suggestion is welcome! Last edited by Adam; 07-11-2020 at 02:13 AM. Reason: fixed embeds

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07-11-2020, 12:33 AM	#2
slartibartfast01 Pentaxian Join Date: May 2015 Photos: Gallery Posts: 1,931	Originally posted by detour Hey...It was around 2:30 pm, sunny day. I started shooting with my K-50 and found almost all-dark photos output through the viewfinder while it was all fine through the LV mode. I tried different lens and things happened again. through LV [auto]: through viewfinder [auto]: through viewfinder [Av]: BTW It worked well using [M] mode through viewfinder: All tests above used matrix metering. Any suggestion is welcome! Light entering the viewfinder can cause metering issues. Try covering the viewfinder.

07-11-2020, 12:40 AM	#3
Auzzie-Phoenix Veteran Member Join Date: Sep 2014 Photos: Albums Posts: 1,020	That's some weird firmware display for a K-50. That aside, your problem might be aperture block related. It could also be the exposure sensor at the bottom of the mirror box housing. The lens you were using... did it have an aperture ring, or was it fully automatic, or a PLM lens? If it had an aperture ring, then it would make sense for the exposure to be fine using manual mode if the lens isn't set to Auto or A. If it's something like the 18-55 kit lens, then all images would have been dark with aperture block issue unless the aperture solenoid temporarily worked after several shots. More testing should be done, especially after the camera has been sitting for a while. here's a link to the aperture block thread: Dark exposure problems on K-30 or K-50? Read me first! - PentaxForums.com

07-11-2020, 03:50 AM	#4
photogem Site Supporter Join Date: Apr 2015 Posts: 3,522	Originally posted by detour I started shooting with my K-50 and found almost all-dark photos output through the viewfinder while it was all fine through the LV mode. I tried different lens and things happened again. Very typical symptoms for aperture-block-failure, also called dark-image-syndrome The solenoid of the diaphragm-control-block is stuck! In LV the solenoid actuates twice but it is stuck the first actuation. Because the solenoid actuates twice and the mirror goes down this releases energy, the solenoid gets those extra milli-amperes which brings it to release when actuating this second time. This is why in LV it still works, even if metering is not acurate. But after a while it fails as well in LV! Originally posted by detour BTW It worked well using [M] mode through viewfinder Because the solenoid is not in action in M-Mode! You can do those tests: Detection of aperture block/diaphragm-block failure/stuck solenoid K-30, K-50, K500 - PentaxForums.com (well, actually you did them already kind of) and then apply: Manual solenoid replacement Pentax K30 / Discharge flash-condenser / Solenoid choice - PentaxForums.com Last edited by photogem; 07-11-2020 at 03:57 AM.

07-11-2020, 03:58 AM	#5
microlight Site Supporter Join Date: Sep 2011 Location: Hampshire, UK Posts: 2,129	From your photos, there's around a four-stop difference in exposure between the LV and viewfinder shots (AV) - shutter speed 1/6 rather than 1/125 - which is possibly why the auto and AV viewfinder shots look dark. Same exposure in viewfinder manual as in LV (1/6 second) which is why that one looks ok. We'd need to know exactly which lenses you were using to try to help further, I think.

07-12-2020, 06:11 AM	#6
photogem Site Supporter Join Date: Apr 2015 Posts: 3,522	He tried different lenses and had the same problem there. Symptoms are so typical and 99% likelyhood failure of the solenoid.

07-12-2020, 06:15 AM	#7
slartibartfast01 Pentaxian Join Date: May 2015 Photos: Gallery Posts: 1,931	Originally posted by photogem He tried different lenses and had the same problem there. Symptoms are so typical and 99% likelyhood failure of the solenoid. The metering is different though. He seems to have the camera on a tripod so light could be entering the viewfinder.

07-12-2020, 06:34 AM	#8
photogem Site Supporter Join Date: Apr 2015 Posts: 3,522	I can't see a tripod?

07-12-2020, 06:38 AM	#9
slartibartfast01 Pentaxian Join Date: May 2015 Photos: Gallery Posts: 1,931	Originally posted by photogem I can't see a tripod? Hmm you could be right but the metering is definitely different. If it was aperture block wouldn't the metering be the same?

07-12-2020, 10:27 AM	#10
photogem Site Supporter Join Date: Apr 2015 Posts: 3,522	I think we have to wait what our new member comes up with. Problem is, that some ask a question, members answer (or pretend to answer) but then there is zero reply, such as with this one: DA 50mm 1.8 aperture stuck after drop - PentaxForums.com

07-12-2020, 10:56 AM - 1 Like	#11
microlight Site Supporter Join Date: Sep 2011 Location: Hampshire, UK Posts: 2,129	That's a little rude; we're only looking for clarity.

07-12-2020, 09:40 PM	#12
photogem Site Supporter Join Date: Apr 2015 Posts: 3,522	Originally posted by microlight That's a little rude; we're only looking for clarity. What / which part is a little rude?

07-12-2020, 11:30 PM	#13
microlight Site Supporter Join Date: Sep 2011 Location: Hampshire, UK Posts: 2,129	'...answer (or pretend to answer)'

07-13-2020, 04:07 AM	#14
photogem Site Supporter Join Date: Apr 2015 Posts: 3,522	Originally posted by microlight '...answer (or pretend to answer)' That wasn't coined to anybody here but just in general. Everybody here tried just to help

07-13-2020, 09:06 AM	#15
microlight Site Supporter Join Date: Sep 2011 Location: Hampshire, UK Posts: 2,129	Okay.