Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-09-2015, 07:34 AM   #16
Pentaxian




Join Date: Oct 2006
Location: Chicago suburb, IL, USA
Posts: 1,535
QuoteOriginally posted by stevebrot Quote
...or having the A-contacts. If the "A" contact ("*" in diagram below) is not detected, AF will not be attempted.
It's good that the OP found a cure, but I feel compelled to add a post because I believe this statement is not accurate. IIRC the "A" contact transmits aperture information (min/max and Av from the lens if the aperture ring is set to "A").

The "Data" contact, which is the bottom-most of the seven body contacts (and not shown in the above diagram), transmits the rest of the lens info (model, screw drive/SDM, MTF in FA and later models, etc). If this contact is not functioning correctly, then the body can assume an MF lens is mounted.

Scott

03-09-2015, 01:19 PM   #17
Senior Member




Join Date: Apr 2014
Location: Melbourne, Australia
Posts: 142
Original Poster
Ah well, it's not over.

Midway through a session with the Sigma the AE went on the blink and the EXIF data for those shots reckoned the focal length was 2.5 m!

Swapping back to Pentax lenses brought back the AF failure and the tickle and clean routine hasn't fixed it.

It's a waning moon. Maybe that's it.

Any mileage do you think in getting a drop of WD40 into that contact? It's all I've got and am likely to have for a week.
03-09-2015, 01:24 PM   #18
Pentaxian




Join Date: Oct 2011
Location: Savannah, GA
Posts: 5,002
QuoteOriginally posted by Sigmund Quote
Any mileage do you think in getting a drop of WD40 into that contact? It's all I've got and am likely to have for a week.
Don't do that. Electronic contact cleaner is ok, but WD40 is oily and could spread into other parts. (And does it even help conductivity?) Contact cleaner is what you want -- any hardware or auto parts store...
03-09-2015, 01:35 PM   #19
Senior Member




Join Date: Apr 2014
Location: Melbourne, Australia
Posts: 142
Original Poster
QuoteOriginally posted by snostorm Quote
It's good that the OP found a cure, but I feel compelled to add a post because I believe this statement is not accurate. IIRC the "A" contact transmits aperture information (min/max and Av from the lens if the aperture ring is set to "A").

The "Data" contact, which is the bottom-most of the seven body contacts (and not shown in the above diagram), transmits the rest of the lens info (model, screw drive/SDM, MTF in FA and later models, etc). If this contact is not functioning correctly, then the body can assume an MF lens is mounted.

Scott
Thanks Scott. Didn't notice your post as I was replying from p.1. Will focus on that contact (ahem).

---------- Post added 03-10-15 at 07:46 AM ----------

QuoteOriginally posted by vonBaloney Quote
Don't do that. Electronic contact cleaner is ok, but WD40 is oily and could spread into other parts. (And does it even help conductivity?) Contact cleaner is what you want -- any hardware or auto parts store...
Thanks vB. Will see if I can find some.

03-09-2015, 05:56 PM   #20
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,263
QuoteOriginally posted by snostorm Quote
It's good that the OP found a cure, but I feel compelled to add a post because I believe this statement is not accurate. IIRC the "A" contact transmits aperture information (min/max and Av from the lens if the aperture ring is set to "A").

The "Data" contact, which is the bottom-most of the seven body contacts (and not shown in the above diagram), transmits the rest of the lens info (model, screw drive/SDM, MTF in FA and later models, etc). If this contact is not functioning correctly, then the body can assume an MF lens is mounted.

Scott
You are correct. I have edited my original post.


Steve
03-09-2015, 09:57 PM   #21
Senior Member




Join Date: Apr 2014
Location: Melbourne, Australia
Posts: 142
Original Poster
Well once today I was able to return to AF with a tickle (of the 3rd contact) followed by a lens swap. But without a change of lens that setup switched to MF while I was hiking!

Wineglass Bay followed by Hazards Beach, Freycinet NP, Tasmania, Australia.
Attached Images
   
03-10-2015, 10:21 AM   #22
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,263
It sounds like maybe a service call may be in order.


Steve
03-10-2015, 12:50 PM   #23
Senior Member




Join Date: Apr 2014
Location: Melbourne, Australia
Posts: 142
Original Poster
Yes indeed. Not possible though as I'm travelling. It's back to the MF of my youth!

03-11-2015, 10:30 AM   #24
Veteran Member
rburgoss's Avatar

Join Date: May 2008
Location: San Jose, Costa Rica
Photos: Gallery | Albums
Posts: 972
Hmmmm... so the problem came back? As I understand, it came back after using the same Sigma that showed the problem the first time?

If that's the case, I can see a pattern here, and its not your camera who needs servicing!
03-11-2015, 12:49 PM   #25
Senior Member




Join Date: Apr 2014
Location: Melbourne, Australia
Posts: 142
Original Poster
Yes, though it returns as well after being tickled back to life after the Sigma bite.

Do you have the K3 rburgoss? If so can you tell me whether the 3rd contact down is recessed?
03-11-2015, 01:58 PM   #26
Veteran Member
rburgoss's Avatar

Join Date: May 2008
Location: San Jose, Costa Rica
Photos: Gallery | Albums
Posts: 972
QuoteOriginally posted by Sigmund Quote
Yes, though it returns as well after being tickled back to life after the Sigma bite.

Do you have the K3 rburgoss? If so can you tell me whether the 3rd contact down is recessed?
I can do better. This is my K3's mount contacts. They are identical to my K20D's. The 3rd contact is recessed. The 7th contact is (seems) gold.
Attached Images
View Picture EXIF
PENTAX MX-1  Photo 
03-11-2015, 07:32 PM   #27
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,263
QuoteOriginally posted by Sigmund Quote
If so can you tell me whether the 3rd contact down is recessed?
QuoteOriginally posted by rburgoss Quote
The 3rd contact is recessed
The third contact on the body is always recessed.


Steve
03-11-2015, 08:18 PM   #28
Senior Member




Join Date: Apr 2014
Location: Melbourne, Australia
Posts: 142
Original Poster
Thanks. I thought that'd be too simple a diagnosis.

The body produced some odd yellow casts amongst the normal hues in today's shoot. Sigh.
03-21-2015, 11:15 AM   #29
Senior Member




Join Date: Apr 2014
Location: Melbourne, Australia
Posts: 142
Original Poster
Update: the body has returned to good behaviour & I've no idea why. The Sigma doesn't reproduce the problem.

Not very confidence inspiring.

Thanks again all for your help.
03-21-2015, 03:16 PM   #30
Veteran Member
rburgoss's Avatar

Join Date: May 2008
Location: San Jose, Costa Rica
Photos: Gallery | Albums
Posts: 972
QuoteOriginally posted by Sigmund Quote
Update: the body has returned to good behaviour & I've no idea why. The Sigma doesn't reproduce the problem.

Not very confidence inspiring.

Thanks again all for your help.
That is quite disturbing. Did you used the camera this days and just today it started be having normal, or is it that you didn't used it and just today you noticed it came back to normal behavior? If camera was not used, was the battery in it charged?

It is important to pinpoint and be able to reproduce the conditions on which the erratic behavior triggers. That will be the only way to know for sure which "link" is responsible: body, lens, battery, shooting conditions, etc.

Pls, keep us posted if anything happens again.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
aperture, body, camera, contact, lens, mf, pentax help, photography, post, scott, settings, thanks, troubleshooting
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
645 adapter stuck on k3 mccarvindh Pentax K-3 6 03-14-2014 07:06 PM
AF/MF button stuck mde1970 Troubleshooting and Beginner Help 4 08-27-2012 02:32 AM
KX stuck in autofocus, but switch is stuck in MF icywarm Troubleshooting and Beginner Help 4 08-07-2012 07:21 AM
k100d MF/AF toggle switch stuck in MF summatusmentis Pentax DSLR Discussion 9 11-26-2009 03:52 PM
New to K10D stuck with MF istDL-K10D Pentax DSLR Discussion 21 10-17-2008 10:13 AM



All times are GMT -7. The time now is 06:31 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top