[willytwodog]

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I have a K 30 with the failure. I use it almost daily with any lens with an aperture ring. Set green button to tv, push green button to stop down meter( at aperture set) and happily shoot away............Push green button before each shot.............works for me..........

[mcgregni]

I accept what you guys are saying, in your particular situations. The green button will meter ..... but is the camera actually stopping down your lenses?


The question is what exact failure we're talking about and what control the camera has over the lens aperture. What I am trying to point out is that if the camera cannot control the aperture with the ring set to the A position, then it could not do that with the ring set to any other position.

[Adam]

The question is what exact failure we're talking about and what control the camera has over the lens aperture. What I am trying to point out is that if the camera cannot control the aperture with the ring set to the A position, then it could not do that with the ring set to any other position.

The aperture ring on Pentax cameras is mechanical, and it limits the minimum possible aperture setting to whatever is set on the ring. Of course, whether the (malfunctioning) actuator in the camera will actually move the aperture lever all the way to the selected setting is another story. I guess there is a little bit of unpredictability here depending on the nature of the individual failure. On a theoretical level I still wouldn't expect metering to be consistent.

Let's see what the OP's investigation yields!

[iheiramo]

The question is what exact failure we're talking about and what control the camera has over the lens aperture. What I am trying to point out is that if the camera cannot control the aperture with the ring set to the A position, then it could not do that with the ring set to any other position.

A lot of people have been able to fix the camera with chancing the solenoid. There is a long thread about fixing the camera, but I haven't spend too much time trying to understand it. You might find the answer to your questions there.

I have been satisfied with the fact that with manual lens it works just as good as my K5. It's all I need at the moment.

[mcgregni]

The aperture ring on Pentax cameras is mechanical, and it limits the minimum possible aperture setting to whatever is set on the ring. Of course, whether the (malfunctioning) actuator in the camera will actually move the aperture lever all the way to the selected setting is another story. I guess there is a little bit of unpredictability here depending on the nature of the individual failure. On a theoretical level I still wouldn't expect metering to be consistent. Let's see what the OP's investigation yields!

I certainly agree that some tests will be helpful. One issue I think we face is that often the failures as reported are not all exactly the same or are at different stages of development. I see your point that a partly failed lever could operate a diaphragm up to a point. But I'm not getting why it should make any difference whether the aperture ring is in the A position or not .....

I have a bunch of Pentax-M/M42 glass which obviously continue to work as before as they contain no automatics.

AnttiV, I assume you've tried your M type lenses? Were you able to get consistent exposures and good stopped down results at a range of apertures? (I appreciate that it can sometimes be difficult to verify from the resulting photos whether an aperture has actually stopped down or not ....)

[The Squirrel Mafia]

Hi. Unfortunately my K30 is starting to show symptoms of the dreaded Aperture Problem. I have no spare money to ever fix it and will just need to live with it.
However as I've been so poor, the number of actual "new" lenses that I have is relatively small. I have a bunch of Pentax-M/M42 glass which obviously continue to work as before as they contain no automatics.

One of my K-50 bodies was starting to develop this issue. I looked around & figured that I'd try replacing the solenoid. I went ahead & ordered this aperture solenoid plunger from eBay & not risk an unknown new replacement part from some random vendor. I went to Harbor Freight & picked up a soldering iron & a lead-free rosin core solder for about $8. I also had to get this set of electrical screw drivers for about $9, since the ones I had were a bit too short & bulky to unscrew the aperture solenoid plunger screw. I opened up the camera by following these instructions. The fix took me about 3 hours total 'cause of the soldering involved & going to Harbor Freight for those screwdrivers.

The soldering part was the hardest 'cause the replacement part & wires are really tiny. Be patient & work slowly.

Once you have the camera completely open, you have to remove the solenoid wires from the body. By the way, the capacitor is more exposed on the K-30 than on the K-50, so be careful not to touch it. You'll have a shockingly good story to tell the grand kids. Hahaha! To remove the wires, you have to touch the point on the camera where they connect, but you have to be kind of careful. Make sure you move the other wires out of the way or else you could burn them. You gently pull on the wire end you are touching with the soldering iron at the same time & they slip right out once the weld gets hot.

Once you remove both wires from the camera body, you can unscrew & remove the solenoid & then carefully pull the wires off the green aperture plunger solenoid. Just grab them by the end closest to where they connect & gently pull them off. Don't really need to heat them. Then you peel off a very tiny bit of the rubber cover at each end. You can do that with your finger nails.

The easiest way to get the wires to reconnect to the solenoid & camera was to melt some core solder onto a piece of cardboard. You basically heat it up with the soldering iron & it starts to drip. You might have to heat up the drip a few times & keep dragging it around to get a smaller drips out of them. Then you grab the wire, heat up the drip again, & slide the wire into the drip. Do this for each side of the 2 wires. You'll need 4 drips of core solder.

Once you get some core solder on the wires, place the wire end over the solenoid & heat it up & the drip will melt onto the contact part. Just make sure you solder the correct wire to the correct location. When both wires are connected to the solenoid, screw it back in the body.

Now comes the slightly hardest part. Line up the wires to the body & first solder the wire closer to the plunger on the camera body. It's the pink one. Put the end where it should go & touch the core solder with the solder iron & it should melt right on. Do the purple one after.

You're pretty much done. The soldering might not look as clean as it did before the whole fix, but if you're careful & not messy, it'll work just fine. Reassemble the camera & as long as you don't drop any parts, bang up the parts, or accidentally overheat any parts, everything will be good.

So after $60 worth of parts & tools, plus about 3 hours labor, I say it was worth it. If you already have those screwdrivers, a soldering iron, & some solder core, the fix is only $40 plus your time. The fix should be permanent for the rest of the camera's life. It sucks that I had to fix it, but it is what it is. I doubt that Pentax/Ricoh is going to fix Hoya's cost cutting mistake. On the plus side, I've already shot about 800 shots & no issues whatsoever! And like usual, "If you want something done right, you gotta do it yourself."

[stillshot2]

And like usual, "If you want something done right, you gotta do it yourself."

Congrats on your fix! I would never trust myself with such a task haha

[The Squirrel Mafia]

^ I was initially kind of scared to do it 'cause I hadn't done any kind of soldering for many years. I'm talking since I was a kid back in the 80's. When I opened up the envelope with aperture solenoid plunger that I go from eBay, I was like, "Holy dog poop! This thing is tiny!" When I opened up the camera & looked at the area where the wires connected to the body, I was like "Crap! There's hardly any room here & it's all tiny!" Hahaha! But once I started going at it, it wasn't so bad.





^ These pictures are from that thread I linked. The size is very deceiving. It's really small in there.

One thing is for sure. Don't try soldering the wire to the solenoid or body while trying to drip solder core on it at the same time. More than likely you will miss & damage both the body & the solenoid. It'll be very messy too. Once you see how tiny it is, you'll understand why I put the solder core on the wire ends before I tried soldering them to the solenoid & body. Don't even try reheating the contact pad on the body & sticking the wire back in. More than likely you're gonna have shaky hands causing you to miss the contact pad & burn something else.

I think I'd be able to do it much faster if I had to do it again. I do have another K-50 body that hasn't failed, yet......

[AnttiV]

I certainly agree that some tests will be helpful. One issue I think we face is that often the failures as reported are not all exactly the same or are at different stages of development. I see your point that a partly failed lever could operate a diaphragm up to a point. But I'm not getting why it should make any difference whether the aperture ring is in the A position or not .....

I think you're missing a crucial point: it is not the aperture lever that fails, it's a tiny solenoid near the lens mount that controls something (I think most people don't even known what it exactly does, me included) in the aperture selection. Whatever the case, if what you said is true, then think about this: Why the failed camera body makes only DARK images? If the lens defaults to aperture wide open, then the camera MOST DEFINITELY closes the aperture down. The failed exposures are dark, and the ISO and shutter speed values do not change. And if you brighten up a failed exposure in PP, you can clearly see the DoF is much larger than meant, so it clearly has stopped the lens down.

My understanding of the aperture mechanism is this:

There are multiple parts and the aperture block that fails is part of a system that *selects* a correct aperture, but does not physically move the lever. when you select an aperture from the camera, Group A of parts align so that the wanted aperture is the smallest the lens can go when the lever is moved. Then when you actuate the trigger, Group B of parts actually physically moves the lever all the way as far as it goes, which SHOULD be what Group A of parts selected. When the solenoid fails, the "selecting" part doesn't function and always defaults to "all closed up". Group B still works perfectly and thus every exposure is dark.

AnttiV, I assume you've tried your M type lenses? Were you able to get consistent exposures and good stopped down results at a range of apertures? (I appreciate that it can sometimes be difficult to verify from the resulting photos whether an aperture has actually stopped down or not ....)

My aperture block hasn't failed completely (as in, it only occasionally does the dark frame thing), so I cannot be sure. I will need to wait until it fails 100% of the time to test that.

[Not a Number]

See this thread Dark exposure problems on K-30 or K-50? Read me first! - PentaxForums.com

Note this post:

My aperture block failure resulted in overexposed pictures. It stopped stopping down.

K50, in warranty, 6-8 months after purchased new. Fixed by Precision.

For those with lenses that have the "A" setting on an aperture ring-

Step 1:

a.) Mount the lens on the camera.
b.) Set aperture ring to "A" setting.
c.) Take a picture.
d.) Set aperture ring to an aperture value that should take a properly exposed image.
e.) Take a 2nd picture.
f.) Examine both exposures.

If the image you took when the aperture ring was set to "A" is severely underexposed (dark exposure), and the image you took with the aperture ring set to a specific value is NOT underexposed, you more than likely have aperture block failure in your unit. If BOTH exposures are dark, this could indicate a more severe problem with the unit, or there may be an issue with the lens. To rule out lens issues, try again with a different lens. Should the second lens replicate both images with dark exposures, then it might be an issue with the light meter sensor, or the image sensor.

Note it does not say it has to be a manual focus lens with aperture ring.

A simple test would be to try the Optical DOF preview on a failing camera. If it doesn't stop down then I would say the stop-down mechanism is not working at all.

[mcgregni]

I think you're missing a crucial point: it is not the aperture lever that fails, it's a tiny solenoid near the lens mount that controls something (I think most people don't even known what it exactly does, me included) in the aperture selection.

Yes, sure I see that point. What is needed is a good explanation of why that solenoid failure affects the behaviour of A / M / K lenses depending on whether the ring is set to A or to a specific aperture. I don't know the technicalities of that, that's also for sure!

Considering the wide range of opinions here and not all failures being equal, I still think you should be cautious in assuming that all Fseries lenses will stop down correctly with a camera failure when the aperture ring is not in the A position ....(of course FA, F and A series lenses become just the same as M and K types once the aperture ring is not in the 'A' position, so it applies to all these types equally). Your most sure bet would be to use the Takumar types, or those with a Manual/Auto aperture switch set to the M setting, and then the lens stop down action is not dependent on control from the camera.

[AnttiV]

Yes, sure I see that point. What is needed is a good explanation of why that solenoid failure affects the behaviour of A / M / K lenses depending on whether the ring is set to A or to a specific aperture. I don't know the technicalities of that, that's also for sure!

Considering the wide range of opinions here and not all failures being equal, I still think you should be cautious in assuming that all Fseries lenses will stop down correctly with a camera failure when the aperture ring is not in the A position ....(of course FA, F and A series lenses become just the same as M and K types once the aperture ring is not in the 'A' position, so it applies to all these types equally). Your most sure bet would be to use the Takumar types, or those with a Manual/Auto aperture switch set to the M setting, and then the lens stop down action is not dependent on control from the camera.

I'm definitely cautious, but I'm not panicking anymore that the camera will be absolutely useless after it has failed completely. Mine appears to be degenerating rather rapidly, unfortunately. First it was three dark frames in a few weeks, now it seems it's either two a day, or first two everytime I power it up... so not long anymore

But you're absolutely right, we need a good explanation of what that solenoid ACTUALLY does in the grand scheme of things. Unfortunately as Pentax has not apparently never even admitted that this problem even exists, we're not in a hurry to hear from them at least, what the deal is.

My (somewhat educated) guess is like I posted above - that the solenoid is in someway responsible for selecting the desired aperture, but not directly responsible for the actual action of stopping it down by physically moving the lever. (As it is just a solenoid, I would've guessed the otherway around, but oh well. Thankfully I'm not in a position that I'd have to build a digital camera body from the ground up )

[mcgregni]

Have you been able to get consistent stop down metering and stopped down images with your M types lens?

[AnttiV]

Have you been able to get consistent stop down metering and stopped down images with your M types lens?

Well, yes. But then again, I also get consistent stop down metering and stopped down aperture with my automatic lenses most of the time. As I said, the block hasn't failed completely yet, so I have no way of knowing if the consistent exposures result of the lens being one type or another, or just the body still working as intended.

I'll be sure to do more testing once the block has failed to a point that most of the images are dark with an automatic lens.