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Forum: Pentax K-30 & K-50
03-06-2019, 02:08 AM
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So, what do electron tubes have to do with the problem we're supposed to discuss here? Then, add some some vaguely anti-Chinese prejudices, and a sweeping dismissal of differing opinions as naive fantasy... enhanced with a link to a 404 page (it should have lead to page about a work conflict about tightly scheduled toilet breaks in Shinmei's Shanghai factory in 2008).
In other recent postings, Photogem also advised someone to glue in a screw with epoxy (a certain recipe for disaster should you ever want to take out that screw again), and not to use silver solder (forgetting to add that using an acetylene burner is also not recommended).
And to add injury to insult, this is backed by a moderator, who IMO should rather restrain such postings instead of enabling them.
One last remark by me before I'm out of here (and that means the Pentax Forum which I find is increasingly populated by people repeating monologues).
I'm not saying that I know the reason for the problem. But summarily stating that the solenoid is the only culprit simply does not explain why in many cases changing the power supply changes the symptoms. Also, one of the differences between the K-50 and all the later models is that these do not allow using AA-type batteries any more (which presumably lead to the omission of the circuitry needed to adapt to different power source voltages), so the notable difference between these models is just that. Looking at publicly available datasheets for similar solenoids, one can see that there's a clear minimum of holding power at a certain voltage, a deviation in both ways (higher and lower) increases the holding power (see this post K-50 / K-500 Aperture Solenoid fix (DIY with pics) - PentaxForums.com, there's a link to the moatech website where you can find the datasheets.)
Now, one could imagine that a deviation in holding power over time and a deviation in voltage supplied to release the plunger might both play a role here, explaining why mechanical changes (sanding) as well as changing the battery system both influence the symptoms. But this will get summarily dismissed.
So, IMO it's not at all clear that the solenoid is the sole reason for the problem. There are too many unanswered questions here. Changing it is a workaround and might be a permanent solution, nothing more.
Over and out.
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Forum: Pentax K-30 & K-50
02-21-2019, 12:53 PM
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Just FYI and to bring some content instead of conjecture, so that y'all can see for yourselves:
Shinmei Electric
There are no camera solenoids listed there, though. Datasheet doesn't mention type of plastic material. 20.000 actuations also is not a lot. A pause of 5secs between actuations is also not matching the Pentax part.
Company homepage:
Shinmei Electric
You can look at the history page (that our esteemed colleague has censored above) in its unblemished glory.
Shinmei Electric
So, why the secretiveness? It's all public. But there's no mention of camera solenoids, the ones in the list are destined to CD drive doors.
Now what we still don't know is if they made the part for Pentax, especially because this is not the only manufacturer of this kind of solenoid, what one could assume is that if they did, it was a tailor made part, made according to Pentax' wishes.
Or it's a red herring and someone else makes those parts.
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Forum: Pentax K-30 & K-50
02-21-2019, 07:21 AM
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Time to demagnetize your screwdriver, I'd say. This is no valid magnetization test, using two parts either of which may be magnetized, that's just ridiculous and if your expertise is on that level you should keep it to yourself.
Your other statements still aren't helpful without links or sources.
I've said what I've got to say and this is it for me, I won't fall for your bait and go your way endlessly repeating myself. So EOD here.
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Forum: Pentax K-30 & K-50
02-21-2019, 01:42 AM
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The protection on the solder is really just a dot of felt marker paint, maybe to signal that the joint has been checked, you can just unsolder it. Then, unscrew the old part, put in the new one and solder the wires in the same way that they were attached to the old one. It's not difficult provided your solder iron has a tip that's reasonably fine. Just make it hot and solder quickly that the plastic coil carrier doesn't get deformed.
The polarity is only a problem with parts ripped from other devices, it seems there are solenoids where the coil is wrapped the other way rotation-wise, it shouldn't be a problem with your part.
Damage to the camera: it seems that most collateral damage occurs under the top plate of the camera where there are some sensitive ribbon connectors that are easy to screw up; I would recommend not removing the top, just loosening the screws a bit so that the other panels can be wiggled out.
Another common problem is that the AF switch gets misaligned during reassembly, check that it works in both directions before you put the screws back in.
And be careful not to touch the contacts of the flash condensor (battery-like object on the side where there's no grip), it may be charged with high voltage.
Don't be timid, it's less difficult than it seems.
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Forum: Pentax K-30 & K-50
02-18-2019, 08:24 AM
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Finally, someone who sees it the same way. I think he or she's usurping the threads with posts which are based on conjecture.
No source for the statement where the solenoids are made; stating the material is Teflon or PET, no proof; stating that the plunger gets magnetized (it doesn't); stating that the friction in the coil causes the problem (highly doubtful, in my experience the bearing isn't tight enough); putting out unproven FUD against some methods to mitigate the problem; I could go on and on.
That there's a connection to the power supply circuit, as can be easily deduced from the fact that the problem changes when using 1.5/1.2V batteries instead of the LiIon is something he or she prefers to play down OTOH.
I think that the ultimate cause for the problem is still unknown to everyone posting here. I've seen cameras with a white solenoid go bad again after a year, so go figure...
I'd rather have people keeping an open mind than someone hijacking every thread about the problem and reiterating after every new post the things he or she has already said before, that's so tiresome.
Just my 2 cents.
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Forum: Pentax DSLR Discussion
11-12-2018, 04:02 AM
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To throw in my 2 cents:
I dropped into digital when I was given a Pentax K-m, after three years bought me a K-50.
Before, I used a Praktica B, manual focus, aperture priority SLR. Initially, even the K-m overwhelmed me, it took me quite some time to get used to the autofocus and the divers exposure modes.
Now I've moved on to the K-3ii and the K-50 is used occasionally by my wife who's not really into photography, just wants to click away an image or two sometimes.
IMO, for a beginner in digital, the K3, or K5, with their plethora of settings and high end sensors can be both intimidating and unforgiving, in fact amplifying beginner mistakes.
Using a prime lens will severely restrict your freedom of composition, and from watching my wife, composing with a zoom lens is the easiest part of learning to use a DSLR.
So, contrary to many voices here, I'd recommend starting with one of the simpler cameras, like the K-S2 or the K-70, get the feeling how to use them outside of the green mode, don't shun the kit lens, look for the amazing photos done with it here in the forum, and upgrade if you have reached the limits of that gear.
Both cameras have two dials, which was the most limiting factor on the K-m.
So given the limited budget, the K-S2 with a kit lens would seem the logical choice to get the feeling of Pentax's digital system.
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Forum: Troubleshooting and Beginner Help
11-06-2018, 05:59 AM
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The problem with the aperture failure is that at first it doesn't happen all the time, only sporadically, usually on the first shots after some time has passed.
I agree with the others, return it ASAP.
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Forum: Travel, Events, and Groups
10-17-2018, 08:13 AM
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You left out some crucial information: How much time do you plan to spend? The distances you're planning to cover are huge, so all depends on the time. Also, which time of the year?
Other than that, like the others said, don't drive in New York if you can avoid it.
There's a whole lot to see in that part of the world, I'll add the Berkshires, the Adirondacks, the Catskills...
Kingston on the Hudson is a very interesting town, in Poughkeepsie there's the stunning ex-railroad-now-pedestrian bridge...
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Forum: Visitors' Center
09-30-2018, 04:01 AM
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To switch it on or off, press menu, use the rear dial to scroll horizontaly to the playback tab with the triangle icon, use down button to go to bright/dark area.
There's a separate setting for instant review, after you just took the photo, in the 4th camera tab, instant review, then right arrow, down to bright/dark area.
I usually have this active, but not the aforementioned.
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Forum: Photographic Industry and Professionals
09-27-2018, 12:39 AM
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Wasn't this about questions?
I've got one:
Why do you spend large sums on developing excellent lenses, but in the assembly, the quality control leaves much to be desired, so that customers regularly have to buy several times to get one acceptable lens?
It's frustrating to see the lenses' potential in one corner, only to notice the other corner is completely off...
Why don't you just ramp up QC *and* the lens prices and deliver excellency?
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Forum: Troubleshooting and Beginner Help
04-06-2018, 01:18 AM
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Please, do not post such misleading utterings. The cause for the problem is clear as stated by the original poster. There's no need to continue analyzing a solved problem, and you should really refrain from offering 'solutions' that have no relation to the problem at all, as this might only mislead others. Thank you.
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Forum: Pentax K-3 & K-3 II
04-03-2018, 02:59 AM
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Fwiw, my K3 ii was overexposing, too. After some time, I noticed that this was happening only when I used the 16...85mm lens that came with the kit. Careful research showed a tilted aperture lever on the lens, it was not in a 90°angle relative to the lens mount, but about 1mm off tangentially, so that the aperture in the lens would not close down enough to expose the image correctly. After having it repaired on warranty, the exposure is now correct.
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Forum: Pentax Camera and Field Accessories
01-17-2018, 07:14 AM
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I bought a Neewer branded BG-5 grip replacement and immediately returned it. Generally, it was feeling cheap, the buttons were mushy, the on/off switch didn't have clearly defined clicks, the dials didn't feel nice, it started to warp when tightening the mount screw, battery door fasteners were hard to operate and seemed flimsy, no seals, and on top of that it only worked erratically, the dials and buttons didn't work most of the time. Also, the camera put itself to sleep even when the shutter button was depressed.
Conclusion: an awful product without quality control.
That said, Neewer seems to be a reseller (the grip was labeled DSTE iirc), so other products still might be better. I'd recommend buying at a seller that's paying return postage and offers money-back guarantee.
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Forum: Pentax Camera and Field Accessories
01-17-2018, 06:13 AM
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Does it say Pentax, Philippines on the label? I tried a knockoff BG-5 grip from China that felt as you described. Actually, it was really awful, luckily I could return it. Compared to the original genuine K-1 grip, it was a really bad experience. Some buttons didn't work at all, the dials felt cheap, the whole thing was untrustworthy.
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Forum: Pentax K-3 & K-3 II
01-11-2018, 11:15 AM
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Ok, let's sort this out: for some reason you get unexposed or severely underexposed photos.
1st check: switch on the camera, press the red button marked LV just on the right of the viewfinder. You should see what you're pointing the camera at on the LCD display.
If not, the shutter might stay closed or the mirror doesn't swing up. You could check if they move correctly by selecting Sensor Cleaning, then Mirror Up from the last page of the wrench menu, take off the lens before and look into the camera: do you see the sensor? (Leave this mode by turning off the camera).
After checking this, report back so that we can see more clearly what's going on.
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Forum: Troubleshooting and Beginner Help
11-03-2017, 05:01 AM
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Joyce,
try to move the switch at the side of the card/adapter into the lock position before inserting it into the computer.
That way, the card is read-only and this prevents the computer from doing strange things to the file system on the card (which they do).
Just be aware that you have to move the switch back before returning the card to the camera (although you get a message if you should forget), and that you'll have to delete pictures from the card in the camera, not in the computer.
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Forum: Pentax SLR Lens Discussion
10-30-2017, 08:35 AM
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Firstly, I cannot comment on the Sigma, not having encountered one yet. Did you look at the lens reviews on this site?
Secondly, while it may be true that really bad lenses aren't being made anymore, it is, alas, also true that of each given lens there are superb and awful exhibits and everything in between.
The 18-55 kit lens is actually quite decent if you get a good one. As with every lens you buy, test it immediately, and exchange it if you find it out of tolerance.
How to Check Your Lens for Decentering - Articles and Tips | PentaxForums.com
If you want a little more range, you could also look for a kit with the 18-135 lens which is also quite good, a bit better than the 18-55 (if you're lucky) and has a much smoother AF without that old time screw drive. It is more fun to use.
Something to have in mind regarding the K-50: it is prone to suffer from the infamous aperture block failure (see the longish thread in the K-30/50 subforum on this site), so it might be advisable to buy an extended warranty if the price is reasonable.
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Forum: Pentax K-30 & K-50
10-26-2017, 12:46 AM
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Torben,
the aperture block failure typically manifests itself with photos being underexposed (too dark), especially the first shot after powering on the camera after a period of rest, and using a fully charged Li-109 battery.
Let the camera rest overnight, power on and immediately take several shots in manual mode, if the first one is very much darker, then you've got the problem.
I don't think the failure could lead to overexposed (brighter) images because this would mean the aperture staying wide open, which is not controlled by the solenoid, but by the stopping-down controller that will only kick in if the solenoid works correctly (otherwise closing down all the way leading to the problem).
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Forum: Troubleshooting and Beginner Help
10-02-2017, 05:50 AM
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If the camera powers on and shows a green battery symbol, there shouldn't be a power problem.
This sounds like a shutter problem to me. Edit: s/o suggested above what I had in mind, never mind...
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Forum: Pentax DSLR Discussion
09-07-2017, 02:00 AM
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FWIW, the typical symptom of the dreaded aperture block failure is pictures being underexposed, often the first one after activating the camera. This is because the mechanism stopping the aperture lever from going down all the way fails, so that the aperture closes completely.
Overexposure on the other hand would mean that the lever does not move at all.
Does this happen with all your lenses? What happens if you do a DOF preview with a small aperture (IIRC you have to map this to the Raw/Fx button first)?
On the other hand, the symptom showing on the first shot is similar to the usual aperture failure...
Are you using NiMH batteries or the LiIon one?
I'm just trying to clear up if you really have the usual aperture failure here or something different.
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Forum: Troubleshooting and Beginner Help
08-31-2017, 12:52 PM
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It certainly sounds like it - you should take two pictures right after another and check the exposure values, if they're the same, but the first picture is significantly darker, I'd say you've been hit. Hope you still are under warranty with that camera...
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Forum: Repairs and Warranty Service
08-15-2017, 08:25 AM
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You should also keep in mind that batteries will degrade over time. This means the battery will still reach a nominally good voltage level, but the voltage will collapse immediately when you draw a sufficiently high current. The Pentax battery check function seems to be quite rigorous, and it's very good at detecting such batteries, which usually means the camera won't power on at all.
In other devices drawing less current, these batteries may very well continue working.
In my experience, Eneloops and only Eneloops will work reliably, I tested other renowned brands, which stopped working much earlier.
You could try with a set of alkalines, if the camera powers up, get a pack of Eneloops.
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Forum: Troubleshooting and Beginner Help
08-04-2017, 08:46 AM
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If you are a patient guy, have some experience in fine mechanics and it's not your first encounter with a soldering iron, the fix is not that difficult. (But if you've to buy a soldering iron first, you'd maybe be better off to find someone and have her or him do this for you.)
I was in the same situation like you, my K-50 started to fail when I was on a trip and only some weeks before another one.
After watching the video linked above and finding a replacement in an old laptop's CD drive, I gave it a go and it has not failed again since then.
For the other body, I'd recommend using Eneloops, because this seems to postpone the failure.
With the recent improvements in sensors, the K3ii seems to be somewhat outdated already, so I can understand that you're waiting for its successor.
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Forum: Troubleshooting and Beginner Help
07-07-2017, 08:34 AM
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Update: your aperture block is on the fritz, read more in the K-50 forum.
Fwiw, it's a K-50. Are you sure the aperture block still works? To check, try another lens.
Also, manually move the aperture lever near the lens mount, does it move smoothly all the way from wide open to nearly closed when the aperture is set to A?
Hartmut
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Forum: Pentax SLR Lens Discussion
06-20-2017, 08:40 AM
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There's no easy way to use Prakticar lenses with the Praktica B bayonet on a Pentax body because the flange distance is smaller than that of the Pentax.
An adapter would either lose infinity focus or need a corrective optical system, and afaics, due to the relative rarity of the B mount, neither type exists.
People have machined off parts inside the Praktica lenses to accommodate a Pentax mount, but for a common lens like the 135 this would probably be way too much work.
Hartmut
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