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10-02-2020, 09:59 AM   #106
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QuoteOriginally posted by photogem Quote
amazing news after todays news! Wow



The minus/negative is in 99% strong, it isn't affected by the switch at all



But not because you cleaned the s-witch!



I think you need this hug from somebody else, much closer to you
You're very kind and polite.

Best regards

12-06-2020, 03:15 PM   #107
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Live view and never remove battery like cell phone camera

QuoteOriginally posted by ShawnH Quote
I have a feeling that removing the battery from the camera when not in use can prevent the solenoid from getting magnetized and therefore solve the dark frame problem.. It is probably due to a current leak from the battery that over long term storage does the damage. It is difficult to test this theory but perhaps smarter minds on this forum can advise.
Pentax should make camera like cell phone that never remove battery and even one month never use it never fails 24/7 ( my android S6 5 yrs old. ) and uses live view. My ks2 three years old, 2k exposures fails in three weeks with no battery and by using viewfinder to shoot fails like aperture failure. What i did was insert battery one day before shooting and using live view indoor and outdoor works well. I don't know if cell phone has solenoid but my android never fails in any place when i need it to take photo.Current leak due to a failure of one electronic part which seldom happen. Aperture block happens to pentax because poor engineering concepts. My Cannon do not have that phenomena.

I took indoor photo for my ks2 ( live view ) half to wall and adjacent half to window during sunny day and the result was the wall is dark and the window is acceptable, this means the aperture works but the resulting photo is bad on the wall and acceptable on the window, this has nothing to do with aperture failure, do you think aperture works half only? Hey pentax wake up, I don't like 50/50 photo ,check your light sensors, you selected only half that is better for you and the other half is bad.

Smarter mind not needed shawn , just common sense.
12-06-2020, 10:54 PM - 1 Like   #108
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As said before, it has zero connection with the battery.
Why and how well (because it is still limited but just seems to be o.k.) LiveView works is also explained here in all detail:
How to detect aperture block failure on Pentax K-S1 (and K-S2) - PentaxForums.com

So this is why you have that bad photo! It meters wrong!
12-07-2020, 06:48 AM   #109
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live view

QuoteOriginally posted by photogem Quote
As said before, it has zero connection with the battery.
Why and how well (because it is still limited but just seems to be o.k.) LiveView works is also explained here in all detail:
How to detect aperture block failure on Pentax K-S1 (and K-S2) - PentaxForums.com

So this is why you have that bad photo! It meters wrong!
I don't set up metering because it is in full auto mode.

Is there any news from class action lawsuit against ricoh?

12-07-2020, 07:05 AM   #110
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Interesting, how would cold affect this behaviour? Then again, we don't expect a cold winter even in northen countries anymore, don't we?
12-07-2020, 10:57 AM   #111
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This forum should ask the appropriate government agency to let pentax ricoh to recall all cameras affected by so called aperture block, sensor defect or black photo whatsoever.

Let this camera send to failed museum to go with kodak, yashica, etc..
12-07-2020, 02:41 PM - 1 Like   #112
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QuoteOriginally posted by Penview52 Quote
This forum should ask the appropriate government agency to let pentax ricoh to recall all cameras affected by so called aperture block, sensor defect or black photo whatsoever.

Let this camera send to failed museum to go with kodak, yashica, etc..
This forum? Most failures have occurred after the end of the warranty period. This forum is an enthusiast site. I suggest if you wish to take any action, the best action to take would be to replace the green solenoid with a white one from an older donor camera yourself. Advice on how to do that is posted in several places on this forum.
12-08-2020, 07:07 AM   #113
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A Pentax is a Pentax.
Anyone who has enjoyed this technology since the 1970s knows what's on their hands.
It is a perhaps old technology, but it gives the possibility to learn how to use a state-of-the-art electronic sensor with the electromechanical resources of that time.
It teaches you how to handle optics and create amazing situations.
With an Android you will only experience the thrill of pressing a button and seeing the photo. There's an audience for that and it's respectable.
As for my Ks-2 it still walks great with all its original components.
You simply have to do regular maintenance with proven services and I can assure you that you shoot your photos for many years to come.
Attached a couple of photos of the Beautiful Valley of Mendoza Argentina, taken this weekend in AUTO viewer mode, where it is shown that the whole system works properly.
I take this opportunity to wish all the enthusiasts (as Mark says) a very happy Christmas and prosperous 2021.
Best Regards

Attached Images
View Picture EXIF
PENTAX K-S2  Photo 
View Picture EXIF
PENTAX K-S2  Photo 
12-08-2020, 03:20 PM   #114
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https://www.pentaxforums.com/forums/members/109116-penview52/albums/13848-ks2/

One photo with out dark part and the other with dark part. Do you think this is a failure of aperture or the light sensor ( pixels ) not activated to compose the photo. Needs your analysis.




Last edited by MarkJerling; 12-09-2020 at 01:28 PM. Reason: Fixed links.
12-08-2020, 03:49 PM   #115
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QuoteOriginally posted by Penview52 Quote
https://www.pentaxforums.com/forums/members/109116-penview52/albums/13848-ks2/

One photo with out dark part and the other with dark part. Do you think this is a failure of aperture or the light sensor ( pixels ) not activated to compose the photo. Needs your analysis.
Your link is dead.
Feel free to review this thread: How to upload / link photos - BEGINNERS START HERE - PentaxForums.com
12-08-2020, 11:12 PM   #116
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QuoteOriginally posted by Penview52 Quote
.....Do you think this is a failure of aperture or the light sensor ( pixels ) not activated to compose the photo. Needs your analysis.
Check as described here:
How to detect aperture block failure on Pentax K-S1 (and K-S2) - PentaxForums.com
This analyis will give clear results.
12-09-2020, 06:18 AM   #117
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ks2 photo

QuoteOriginally posted by MarkJerling Quote
Your link is dead.
Feel free to review this thread: How to upload / link photos - BEGINNERS START HERE - PentaxForums.com
Penview52's Album: KS2 - PentaxForums.com

Try again if this works.

---------- Post added 12-09-20 at 07:22 AM ----------

QuoteOriginally posted by photogem Quote
Check as described here:
How to detect aperture block failure on Pentax K-S1 (and K-S2) - PentaxForums.com
This analyis will give clear results.
Av mode of ks2 has F5.6 lowest and highest not the same as ks1.


Penview52's Album: KS2 - PentaxForums.com
12-09-2020, 06:28 AM   #118
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QuoteOriginally posted by sergiogonzalez Quote
Hello Pentaforum community:

I am Sergio González Pagliara, from Argentina, electromechanical engineer, postgraduate degree in welding and amateur of photography.
Always admire Asahi Pentax's technology and achieve my first Asahi Pentax ME equipment in 1978. Use it intensively until 2005 without any problems in your electronic exposure system. This equipment featured Asahi Pentax 1:7 lenses and an Vivitar 75-205 telezoom, which still work perfectly today.
I entered digital photography in 2005, with various cameras until finally in October 2015 I decided to have a reflex system again. Having optics in good condition, I decided on a Pentax KS 2 equipped with a DA 18-135 Pentax telezoom, which at the time was a good economic/technical option to re-enter good photography and in passing be able to use the old optics.
Everything went well with the KS 2 until August 2019 and with 7000 shots when the diaphragm opening problems or dark photographs began. At first occasional and then it was aggravated to almost impossible its operation.
So I started researching at Pentaforum and found a Photogem post where it describes the history of the development of solenoids applied in Pentax machines. Here's the link for anyone who wants to read it.
A LITTLE BIT OF HISTORY: Development of the solenoid in Pentax cameras - PentaxForums.com
What struck me most is that the main constructive difference between the green solenoid (Chinese) and the old white solenoid (Japanese) is the construction of the reel. PET green, cheaper material and PTEF white, more expensive Teflon material. This led me to think of some considerations regarding the operation of the solenoid:
a) The PET reel increases the coefficient of rubbing of the Plunguer inside the reel when moving.
b) Batteries after 4 years of use have lost efficiency and their voltage decreases rapidly after being recharged (there are many reviews that using good quality AA batteries on the K50, problem is controlled)
c) The material with which the magnet body is built and the Plunguer himself may have gained some magnetism after many cycles
These three considerations led me to try to control the first. For this I obtained a Teflon-based lubricant (PTEF) which I applied only to the PET reel. The consequence was that the opening Block directly stopped working. When the lubricant is passed to the Contact Mirrors of the Plunguer and magnet body, they are glued by surface tension and viscosity of the lubricant, and the diaphragm was always closed.
In the face of this result, disassemble the solenoid of the camera again, disassemble its parts and whit isopropilic alcohol clean the two reels internally, the magnet body and the Plunguer.
When I reassembled the camera at first its walked well, but after two or three days without using it, its took dark photos again in the first few shots.
This led me to believe that the pulse of electric current sent by the camera does not last more than 1/5 of a second, as the opening block is designed to reach a speed of up to 5 shots per second. If the batteries are already weakened, the rubbing coefient is high, and there is suspicion of remaining magnetisms in the metals, there is no other left for the solenoid to stick and as a result the closed diaphragm. From this reasoning is that some forum participants suggest beveling the edges of the Plunguer and decreasing the area of contact with the magnet body, so that the effects of the three listed causes can be lessened.
Already about to proceed to vary the geometry of the Plunguer, I thought I'd use a solid lubricant. It was a coincidence that on my workbench it had graphite powder for the lubrication of locks. Place a very small amount of fine graphic powder inside each reel, and with a small brush I scrub the Plunguer with this graphite. Mount the solenoid and the camera hasn't failed again. (it is very important to keep the cleaning of the reels and solenoid metals. The fat of the fingers can cause problems)
I have almost 1500 shots after this solid lubrication and the solenoid is doing wonders with a very smooth and safe operation.
The following reasoning may apply:
Graphite decreases the coefficient of pet friction, forms a thin separating layer in the mirrors of the Plunguer and magnet body, which improves or decreases the attraction force that can be generated by the eventual magnetism of the metals. This improvement makes even with weakened batteries the solenoid operates and allows the opening block system to select the diaphragm opening obtained by the processor.
Graphite powder from the soft mine of an HB pencil can be easily obtained.
Logically you should be very thorough in the welding procedures of the cables, observe that the graphite is used in the amount necessary so that it does not contaminate other camera devices, observe the correct alignment of the Plunguer with the rest of the solenoid and the lever of the opening block and ensure that the polarity of the magnet and/or cables is correct.
I'll allow myself to use some Photogem photos to define the names of each part of the solenoid.
My native language is Spanish. I apologize to the community for my little Englishman. I wrote the text in Spanish and translated it into English with an automatic translator. Then correct this translation so that it can be understood.
I hope it will help many to repair their camera at no higher cost and confirm that Pentax is perhaps the best camera on the market.
Best Regards and Happy 2020.

Sergio Gonzalez Pagliara
Great article. Thanks!
12-09-2020, 01:29 PM   #119
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QuoteOriginally posted by Penview52 Quote
Penview52's Album: KS2 - PentaxForums.com

Try again if this works.

---------- Post added 12-09-20 at 07:22 AM ----------



Av mode of ks2 has F5.6 lowest and highest not the same as ks1.


Penview52's Album: KS2 - PentaxForums.com
I fixed your links above.
12-09-2020, 01:34 PM   #120
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QuoteOriginally posted by Penview52 Quote
Penview52's Album: KS2 - PentaxForums.com

One photo with out dark part and the other with dark part. Do you think this is a failure of aperture or the light sensor ( pixels ) not activated to compose the photo. Needs your analysis.


There's no failure evident in those images. Check the EXIF data. Your one image was shot at an aperture of F5.6 and a shutter speed of 1/80. Your other image was shot at an aperture of F4.5 and a shutter speed of 1/8. Also, follow photogem's link posted above and do those checks to determine if your camera is working correctly or not.
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