Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-26-2012, 07:16 AM   #1
Tylos
Guest




Pentax K-x and Pentax-FA lens compatibility

I just purchased a Pentax K-x and I got a stock 18-55mm lens with it. I also have an old Pentax MZ-50 camera with a SMC Pentax-FA 28-200mm lens.

I have attached the Pentax-FA 28-200mm lens to my new Pentax K-x and have found that in Auto Pict mode all the shots are over exposed. To get round the problem, I have to set the camera to -3 with the Av button whenever I use the Pentax-FA 28-200mm lens

Any ideas as to what may be causing the problem

03-26-2012, 07:17 AM   #2
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 42,341
Is the aperture ring not in the A position?
03-26-2012, 07:43 AM   #3
Tylos
Guest




Hi Adam,
thanks for your prompt reply. Yes, the lens aperture ring is set to the 'A' position. In fact, the camera will only operate with the lens ring in the 'A' position.
Thanks
Tylos
03-26-2012, 07:52 AM   #4
Senior Moderator
Loyal Site Supporter
Parallax's Avatar

Join Date: Apr 2008
Location: South Dakota
Photos: Gallery
Posts: 15,544
QuoteOriginally posted by First Poster Quote
In fact, the camera will only operate with the lens ring in the 'A' position.
The lens ring does not have to be in the 'A' position for the camera to operate. There is a menu option to allow use of the aperture ring.

03-26-2012, 08:06 AM   #5
Pentaxian
JinDesu's Avatar

Join Date: Jun 2011
Location: New York City
Photos: Gallery
Posts: 5,625
QuoteOriginally posted by Tylos Quote
I just purchased a Pentax K-x and I got a stock 18-55mm lens with it. I also have an old Pentax MZ-50 camera with a SMC Pentax-FA 28-200mm lens.

I have attached the Pentax-FA 28-200mm lens to my new Pentax K-x and have found that in Auto Pict mode all the shots are over exposed. To get round the problem, I have to set the camera to -3 with the Av button whenever I use the Pentax-FA 28-200mm lens

Any ideas as to what may be causing the problem
Is it only in Auto Picture mode? Have you tried using Av mode with both lenses at the same Aperture setting and ISO setting to see if they give the same shutter speed value?

Can you post some pictures from both to this forum so we can judge the settings the camera chose?
03-26-2012, 08:14 AM   #6
Veteran Member
crewl1's Avatar

Join Date: Jul 2010
Location: Los Angeles, CA
Photos: Gallery | Albums
Posts: 9,796
Do the aperture blades snap back easily or are they possibly a bit sticky?
Contacts clean on both the lens and camera?
How does it behave in manual or av?
03-27-2012, 01:31 AM   #7
Tylos
Guest




Hi All,
Thanks for your responses.
Parallax is correct, I set the camera to enable the camera to be used with the lens aperture ring in use and now when I take shots using the aperture ring the exposure is OK at all aperture settings in the AUTO PIC mode. However, with the lens ring set back to Auto, the shots are still over exposed and I have to compensate by adjusting the AV button to -2 or -3.
I also have an old Pentax FA 28-70 lens that came with my Pentax MZ-50 and this works fine with the camera when the aperture ring is set to Auto. So I guess my FA 28-200 lens has a problem. I did inspected and clean the contacts on both lenses.
Thanks
03-27-2012, 09:47 AM   #8
Veteran Member
Docrwm's Avatar

Join Date: Sep 2010
Location: Somewhere in the Southern US
Photos: Gallery | Albums
Posts: 11,275
QuoteOriginally posted by Tylos Quote
Hi All,
Thanks for your responses.
Parallax is correct, I set the camera to enable the camera to be used with the lens aperture ring in use and now when I take shots using the aperture ring the exposure is OK at all aperture settings in the AUTO PIC mode. However, with the lens ring set back to Auto, the shots are still over exposed and I have to compensate by adjusting the AV button to -2 or -3.
I also have an old Pentax FA 28-70 lens that came with my Pentax MZ-50 and this works fine with the camera when the aperture ring is set to Auto. So I guess my FA 28-200 lens has a problem. I did inspected and clean the contacts on both lenses.
Thanks
Glad part of it got straightened out. Shine a light down the barrel of the 28-200 and look at the aperture blades - they should look clean and dry. They should move nearly instantly in a sharp fashion from one aperture setting to another. If you see anything that looks wet or sticky, or they move sluggishly, you have found your problem. Good luck.

03-27-2012, 11:48 PM   #9
New Member




Join Date: Mar 2012
Posts: 1
Hi All,
Just finished shining a light down the lens barrel (Docrwm's suggestion) and sure enough, the aperture blades are sticking. Is it possible for me to fix this myself or is the lens now useless.
Thanks for all your comments and suggestions.
Cheers
03-28-2012, 05:29 AM   #10
Pentaxian
unixrevolution's Avatar

Join Date: Apr 2009
Location: Waldorf, MD
Photos: Gallery | Albums
Posts: 1,858
QuoteOriginally posted by Tylos Quote
Hi All,
Just finished shining a light down the lens barrel (Docrwm's suggestion) and sure enough, the aperture blades are sticking. Is it possible for me to fix this myself or is the lens now useless.
Thanks for all your comments and suggestions.
Cheers
You may not be able to fix it easily yourself, but most competent camera repair places can probably have your FA 28-200 back in working order for a relatively small fee (under $100 bucks, I'm guessing, but don't quote me!)
03-28-2012, 09:33 AM   #11
Veteran Member
Docrwm's Avatar

Join Date: Sep 2010
Location: Somewhere in the Southern US
Photos: Gallery | Albums
Posts: 11,275
QuoteOriginally posted by Tylos Quote
Hi All,
Just finished shining a light down the lens barrel (Docrwm's suggestion) and sure enough, the aperture blades are sticking. Is it possible for me to fix this myself or is the lens now useless.
Thanks for all your comments and suggestions.
Cheers
Sorry but it's better to get to the bottom of it so you can make an informed decision about what to do (if anything).

I'd send it to Eric. Who is Eric you ask? Just the most respected Pentax Service Person around, and reasonable too.

https://www.pentaxforums.com/forums/pentax-film-slr-discussion/105296-pentax-...ndrickson.html

Home
03-28-2012, 10:41 AM   #12
Pentaxian
unixrevolution's Avatar

Join Date: Apr 2009
Location: Waldorf, MD
Photos: Gallery | Albums
Posts: 1,858
QuoteOriginally posted by Docrwm Quote
Sorry but it's better to get to the bottom of it so you can make an informed decision about what to do (if anything).

I'd send it to Eric. Who is Eric you ask? Just the most respected Pentax Service Person around, and reasonable too.

https://www.pentaxforums.com/forums/pentax-film-slr-discussion/105296-pentax-...ndrickson.html

Home
I was under the impression that he only did manual focus lenses.
03-28-2012, 11:04 AM   #13
Veteran Member
Docrwm's Avatar

Join Date: Sep 2010
Location: Somewhere in the Southern US
Photos: Gallery | Albums
Posts: 11,275
QuoteOriginally posted by unixrevolution Quote
I was under the impression that he only did manual focus lenses.
Wow, you may well be right - I have only sent him older MF lenses and never even thought about AF lenses and that he might not do them. His website only says "Lenses 24mm to 500mm) and nothing about MF or AF. Best to check but if I'm wrong (as it may well be the case) I'm sorry.
03-29-2012, 01:46 PM   #14
Pentaxian
unixrevolution's Avatar

Join Date: Apr 2009
Location: Waldorf, MD
Photos: Gallery | Albums
Posts: 1,858
QuoteOriginally posted by Docrwm Quote
Wow, you may well be right - I have only sent him older MF lenses and never even thought about AF lenses and that he might not do them. His website only says "Lenses 24mm to 500mm) and nothing about MF or AF. Best to check but if I'm wrong (as it may well be the case) I'm sorry.
It's not a problem. He may still be able to puzzle it out. He did a Sigma 24mm F/2.8 for me. manual focus, but non-pentax.
03-31-2012, 07:37 AM   #15
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
QuoteOriginally posted by Tylos Quote
Hi All,
Thanks for your responses.
Parallax is correct, I set the camera to enable the camera to be used with the lens aperture ring in use and now when I take shots using the aperture ring the exposure is OK at all aperture settings in the AUTO PIC mode.
Actually, while they might be of appropriate brightness, when you use the aperture ring in any mode but M, it is completely ignored, and only shoots wide open. read the sticky note at the front of Beginner's forum for more on how to use manual lenses (which your lens becomes when you use the aperture rong).

So what you are seeing is indeed consistent with sticky blades shots come out good when shooting wide open, overexposed otherwise.
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!
28-200mm, camera, k-x, lens, pentax, pentax help, pentax k-x, pentax-fa
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Pentax K R lens compatibility rhyazoo Pentax K-r 8 12-06-2011 04:37 PM
Pentax Lens Compatibility with Ricoh camera? Chairman_Xi Pentax SLR Lens Discussion 5 03-08-2011 07:56 PM
Lens compatibility with Pentax KX HaWaIi50 Pentax DSLR Discussion 3 02-07-2011 07:49 AM
Pentax AF Bodies and Lens Compatibility woof Pentax Film SLR Discussion 9 09-04-2010 08:24 AM
Pentax K-x-Sears Lens Compatibility bsamcash Welcomes and Introductions 6 07-31-2010 12:56 PM



All times are GMT -7. The time now is 01:32 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