New K-70 and Aperture Block

reh321 · 04-24-2022, 01:04 PM

Originally posted by S_Miller

Is this just my bad luck? Or do all camera manufacturers have the same issues with quality?
Anyhow, appreciate the forum and a chance to vent a bit, but don't take too seriously the anecdotes you hear. I suspect the failure rate is far higher than understood here. This will be my second failed camera (the other was a KP, but that only cost a few $00). For me, I'm experiencing a 66% failure rate on camera bodies, probably around the 2-3 year old mark.

For awhile I was a Canon user. That ended when I had two Rebels in a row die after having processor problems.
The Rebels ended up in the county dump - there is no alternative way of dealing with processor issues.
The K-30 which came next experienced “Dark Image Syndrome”, but I still use it with old film lenses that allow me to set aperture at the lens.
Later I did purchase a KP, but the K-30 could still serve as my primary camera.

SharkyCA · 04-25-2022, 04:59 AM

Originally posted by swanlefitte

Pretty sure all camera fail eventually. A 2% per year is more likely. I think cameras are designed to last an expected 4 years these days.
I had a canon xl1s camera back in 2005 that took 6 months to repair. It was about a year old.

If you use a plm lens or a manual one, it doesn't exercise the solenoid. Mine failed using it every day when I only used the 55-300 plm for a few months.

The lens type "plm" or "manual" doesn't matter it is the shutter that fails and it is in the camera body that actuates the shutter & the aperture, which is the way I understand it.

swanlefitte · 04-25-2022, 08:07 AM

Originally posted by SharkyCA

The lens type "plm" or "manual" doesn't matter it is the shutter that fails and it is in the camera body that actuates the shutter & the aperture, which is the way I understand it.

The shutter doesn't fail at all. The aperture fails to be open when the shutter works. This is because the solenoid won't open.

The PLM can still be used with this problem because it doesn't use the aperture block. Consequently, using this lens doesn't exercise the solenoid. It is the same as letting the camera sit.

reh321 · 04-25-2022, 09:34 AM

Originally posted by SharkyCA

The lens type "plm" or "manual" doesn't matter it is the shutter that fails and it is in the camera body that actuates the shutter & the aperture, which is the way I understand it.

Exactly what are you talking about?
Yes, the camera body can control the aperture, but in the K-70, a solenoid is involved in that control, and that is the part which typically fails when a K-70 suffers from “Dark image Syndrome”. With a KAF4 lens {which typically includes “PLM lenses”}, or a lens which allows the user to ‘manually’ control the aperture via an aperture ring, the solenoid is not involved in controlling the aperture, and “Dark Image Syndrome” is not an issue. In any case, Dark Image Syndrome” involves pushing the histogram way to the left; the shutter does work - a photo is taken - but it looks dark to the user because the photo uses only the ‘dark’ part of a histogram.

Last edited by reh321; 04-25-2022 at 09:55 AM.

**photogem** · 04-25-2022, 11:39 AM

Originally posted by SharkyCA

The lens type "plm" or "manual" doesn't matter it is the shutter that fails and it is in the camera body that actuates the shutter & the aperture, which is the way I understand it.

Here there are two misunderstandings:
1. PLM is only the motor, it is KAF4 which matters if one wants to use a Pentax with ABF with all modes. KAF4 lenses don't use the solenoid.
2. As others said, the solenoid controls the aperture of the lens but not the shutter.
The shutter is opened and closed by 2 extra strong solenoids though. Maybe this lead to the misunderstanding?

So 3 parts which must go exactly syncronious together:
1. Shutter: 2 strong solenoids, different to:

2. Aperture: 1 solenoid

3 Mirror up: motor

Not a Number · 04-25-2022, 12:32 PM

The solenoid may not be directly involved in closing the iris on a Kaf4 but does it still actuate or not? Kaf4 lenses lack a the aperture actuating lever so it wouldn't matter if the actuator on the camera side moves or not. With lens with aperture rings it would have to move to allow the lens to stop down. Adapted M42 lens do not need the actuator either. I suppose one could leave the M42 lens off and see what the actuator does when you release the shutter.

**photogem** · 04-25-2022, 02:17 PM

Originally posted by Not a Number

The solenoid may not be directly involved in closing the iris on a Kaf4 but does it still actuate or not? Kaf4 lenses lack a the aperture actuating lever so it wouldn't matter if the actuator on the camera side moves or not. With lens with aperture rings it would have to move to allow the lens to stop down. Adapted M42 lens do not need the actuator either. I suppose one could leave the M42 lens off and see what the actuator does when you release the shutter.

An interesting question. I have to wait until I repair another Pentax with KAF4 ability and solenoid plus my DA55-300PLM and check it when open to know for sure.

With a M42 lens the solenoid doesn't actuate, that I have tested.

reh321 · 04-25-2022, 02:49 PM

Originally posted by Not a Number

The solenoid may not be directly involved in closing the iris on a Kaf4 but does it still actuate or not? Kaf4 lenses lack a the aperture actuating lever so it wouldn't matter if the actuator on the camera side moves or not. With lens with aperture rings it would have to move to allow the lens to stop down. Adapted M42 lens do not need the actuator either. I suppose one could leave the M42 lens off and see what the actuator does when you release the shutter.

The solenoid does not move the lever - it stops the lever at the right point, something done by the lens itself if I have set a value with the aperture ring.

My K-30 has lost that ability, so the aperture goes to fully shut down with a DA lens, while my FA stops the movement itself if the aperture ring is set to a particular value.

The camera body knows what kind of lens is mounted, so I believe it provides only the functionality needed.

Not a Number · 04-25-2022, 07:37 PM

You're right the actuator does not move the lever, the spring on the lever does. How ever the lever can't move unless the actuator does.

BTW: The actuator moves on the K10D when no lens is attached. The K10D uses the solenoid based control block.

So if the actuator still moves with a Kaf[sub]4[/4], aperture ring enabled or screwmount lens how is it not getting "exercised"?

Youtu.be

**photogem** · 04-25-2022, 08:29 PM

I'm aware that the lever moves, but if you would have your K100D open, you'd see that the solenoid doesn't move.
That I had tested long time ago:

The white wheel in the middle moves as does the one on the right. But the solenoid stays quiet.

One cannot see the difference from the outside without having the body open.

How it is with a KAF4 cabable body if a KAF4 lens is attached I have yet to find out.

reh321 · 04-26-2022, 04:02 AM

Originally posted by Not a Number

So if the actuator still moves with a Kaf[sub]4[/4], aperture ring enabled or screwmount lens how is it not getting "exercised"?

The solenoid stops actuator motion.
There are other things - such as hitting the end - which can stop actuator motion.
So actuator motion does not imply solenoid activity.
It is a mathematical fallacy to say a=>b means that b=>a.
When photogem is able to look inside, he will report whether there is any solenoid activity.

**photogem** · 04-27-2022, 12:30 AM

Well, might take some time: My next Pentax to repair is a K-S1 which cannot serve to observe the solenoid, one has to attach the front with top to test it, so the solenoid is fully covered.
Might take some time, K30's or 50's show up less these days to be repaired.
Mostly K-S1's and few K-S2's

swanlefitte · 04-27-2022, 06:26 AM

A k50 needed the software update to use kaf4. Someone who can read the script might be able to say how it changes the operation.

I am curious to know for sure.

**JawaT** · 01-21-2023, 01:16 PM

@photogem and other experts:

I bought a K-70 which I think is starting to show the Aperture Block Failure (solenoid) issue. After the camera has been sitting unused for say a day or more and I start using it, the first picture will be severely underexposed (dark). Subsequent pictures are fine. I wanted to confirm that this is the beginning of the dreaded ABF.

Thank you!

**tonyzoc** · 01-21-2023, 01:39 PM - **1 Like**

Originally posted by JawaT

@photogem and other experts:

I bought a K-70 which I think is starting to show the Aperture Block Failure (solenoid) issue. After the camera has been sitting unused for say a day or more and I start using it, the first picture will be severely underexposed (dark). Subsequent pictures are fine. I wanted to confirm that this is the beginning of the dreaded ABF.

Thank you!

Yes, that's how it starts. With my K-S2 it did this for a month or so then stopped working. With my K70, it did this for a few days, then stopped working. Get your white solenoid and tools and read up on the fix procedure. I fixed my K70...maybe 2 yes ago...and its worked perfectly ever since. The repair is easy to do.

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04-24-2022, 01:04 PM	#106
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,180	Originally posted by S_Miller Is this just my bad luck? Or do all camera manufacturers have the same issues with quality? Anyhow, appreciate the forum and a chance to vent a bit, but don't take too seriously the anecdotes you hear. I suspect the failure rate is far higher than understood here. This will be my second failed camera (the other was a KP, but that only cost a few $00). For me, I'm experiencing a 66% failure rate on camera bodies, probably around the 2-3 year old mark. For awhile I was a Canon user. That ended when I had two Rebels in a row die after having processor problems. The Rebels ended up in the county dump - there is no alternative way of dealing with processor issues. The K-30 which came next experienced “Dark Image Syndrome”, but I still use it with old film lenses that allow me to set aperture at the lens. Later I did purchase a KP, but the K-30 could still serve as my primary camera.

04-25-2022, 04:59 AM	#107
SharkyCA Pentaxian Join Date: Sep 2017 Location: Carleton Place, Ontario, Canada Photos: Gallery Posts: 806	Originally posted by swanlefitte Pretty sure all camera fail eventually. A 2% per year is more likely. I think cameras are designed to last an expected 4 years these days. I had a canon xl1s camera back in 2005 that took 6 months to repair. It was about a year old. If you use a plm lens or a manual one, it doesn't exercise the solenoid. Mine failed using it every day when I only used the 55-300 plm for a few months. The lens type "plm" or "manual" doesn't matter it is the shutter that fails and it is in the camera body that actuates the shutter & the aperture, which is the way I understand it.

04-25-2022, 08:07 AM	#108
swanlefitte Pentaxian Join Date: May 2015 Location: Minneapolis Photos: Gallery Posts: 4,068	Originally posted by SharkyCA The lens type "plm" or "manual" doesn't matter it is the shutter that fails and it is in the camera body that actuates the shutter & the aperture, which is the way I understand it. The shutter doesn't fail at all. The aperture fails to be open when the shutter works. This is because the solenoid won't open. The PLM can still be used with this problem because it doesn't use the aperture block. Consequently, using this lens doesn't exercise the solenoid. It is the same as letting the camera sit.

04-25-2022, 09:34 AM	#109
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,180	Originally posted by SharkyCA The lens type "plm" or "manual" doesn't matter it is the shutter that fails and it is in the camera body that actuates the shutter & the aperture, which is the way I understand it. Exactly what are you talking about? Yes, the camera body can control the aperture, but in the K-70, a solenoid is involved in that control, and that is the part which typically fails when a K-70 suffers from “Dark image Syndrome”. With a KAF4 lens {which typically includes “PLM lenses”}, or a lens which allows the user to ‘manually’ control the aperture via an aperture ring, the solenoid is not involved in controlling the aperture, and “Dark Image Syndrome” is not an issue. In any case, Dark Image Syndrome” involves pushing the histogram way to the left; the shutter does work - a photo is taken - but it looks dark to the user because the photo uses only the ‘dark’ part of a histogram. Last edited by reh321; 04-25-2022 at 09:55 AM.

04-25-2022, 11:39 AM	#110
photogem Site Supporter Join Date: Apr 2015 Posts: 3,520	Originally posted by SharkyCA The lens type "plm" or "manual" doesn't matter it is the shutter that fails and it is in the camera body that actuates the shutter & the aperture, which is the way I understand it. Here there are two misunderstandings: 1. PLM is only the motor, it is KAF4 which matters if one wants to use a Pentax with ABF with all modes. KAF4 lenses don't use the solenoid. 2. As others said, the solenoid controls the aperture of the lens but not the shutter. The shutter is opened and closed by 2 extra strong solenoids though. Maybe this lead to the misunderstanding? So 3 parts which must go exactly syncronious together: 1. Shutter: 2 strong solenoids, different to: 2. Aperture: 1 solenoid 3 Mirror up: motor

04-25-2022, 12:32 PM	#111
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	The solenoid may not be directly involved in closing the iris on a Kaf4 but does it still actuate or not? Kaf4 lenses lack a the aperture actuating lever so it wouldn't matter if the actuator on the camera side moves or not. With lens with aperture rings it would have to move to allow the lens to stop down. Adapted M42 lens do not need the actuator either. I suppose one could leave the M42 lens off and see what the actuator does when you release the shutter.

04-25-2022, 02:17 PM	#112
photogem Site Supporter Join Date: Apr 2015 Posts: 3,520	Originally posted by Not a Number The solenoid may not be directly involved in closing the iris on a Kaf4 but does it still actuate or not? Kaf4 lenses lack a the aperture actuating lever so it wouldn't matter if the actuator on the camera side moves or not. With lens with aperture rings it would have to move to allow the lens to stop down. Adapted M42 lens do not need the actuator either. I suppose one could leave the M42 lens off and see what the actuator does when you release the shutter. An interesting question. I have to wait until I repair another Pentax with KAF4 ability and solenoid plus my DA55-300PLM and check it when open to know for sure. With a M42 lens the solenoid doesn't actuate, that I have tested.

04-25-2022, 02:49 PM	#113
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,180	Originally posted by Not a Number The solenoid may not be directly involved in closing the iris on a Kaf4 but does it still actuate or not? Kaf4 lenses lack a the aperture actuating lever so it wouldn't matter if the actuator on the camera side moves or not. With lens with aperture rings it would have to move to allow the lens to stop down. Adapted M42 lens do not need the actuator either. I suppose one could leave the M42 lens off and see what the actuator does when you release the shutter. The solenoid does not move the lever - it stops the lever at the right point, something done by the lens itself if I have set a value with the aperture ring. My K-30 has lost that ability, so the aperture goes to fully shut down with a DA lens, while my FA stops the movement itself if the aperture ring is set to a particular value. The camera body knows what kind of lens is mounted, so I believe it provides only the functionality needed.

04-25-2022, 08:29 PM	#115
photogem Site Supporter Join Date: Apr 2015 Posts: 3,520	I'm aware that the lever moves, but if you would have your K100D open, you'd see that the solenoid doesn't move. That I had tested long time ago: The white wheel in the middle moves as does the one on the right. But the solenoid stays quiet. One cannot see the difference from the outside without having the body open. How it is with a KAF4 cabable body if a KAF4 lens is attached I have yet to find out.

04-26-2022, 04:02 AM	#116
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,180	Originally posted by Not a Number So if the actuator still moves with a Kaf[sub]4[/4], aperture ring enabled or screwmount lens how is it not getting "exercised"? The solenoid stops actuator motion. There are other things - such as hitting the end - which can stop actuator motion. So actuator motion does not imply solenoid activity. It is a mathematical fallacy to say a=>b means that b=>a. When photogem is able to look inside, he will report whether there is any solenoid activity.

04-27-2022, 12:30 AM	#117
photogem Site Supporter Join Date: Apr 2015 Posts: 3,520	Well, might take some time: My next Pentax to repair is a K-S1 which cannot serve to observe the solenoid, one has to attach the front with top to test it, so the solenoid is fully covered. Might take some time, K30's or 50's show up less these days to be repaired. Mostly K-S1's and few K-S2's

04-27-2022, 06:26 AM	#118
swanlefitte Pentaxian Join Date: May 2015 Location: Minneapolis Photos: Gallery Posts: 4,068	A k50 needed the software update to use kaf4. Someone who can read the script might be able to say how it changes the operation. I am curious to know for sure.

01-21-2023, 01:16 PM	#119
JawaT Site Supporter Join Date: Jul 2016 Posts: 59	@photogem and other experts: I bought a K-70 which I think is starting to show the Aperture Block Failure (solenoid) issue. After the camera has been sitting unused for say a day or more and I start using it, the first picture will be severely underexposed (dark). Subsequent pictures are fine. I wanted to confirm that this is the beginning of the dreaded ABF. Thank you!

01-21-2023, 01:39 PM - 1 Like	#120
tonyzoc Loyal Site Supporter Join Date: Jul 2018 Posts: 992	Originally posted by JawaT @photogem and other experts: I bought a K-70 which I think is starting to show the Aperture Block Failure (solenoid) issue. After the camera has been sitting unused for say a day or more and I start using it, the first picture will be severely underexposed (dark). Subsequent pictures are fine. I wanted to confirm that this is the beginning of the dreaded ABF. Thank you! Yes, that's how it starts. With my K-S2 it did this for a month or so then stopped working. With my K70, it did this for a few days, then stopped working. Get your white solenoid and tools and read up on the fix procedure. I fixed my K70...maybe 2 yes ago...and its worked perfectly ever since. The repair is easy to do.