Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
12-26-2011, 12:01 PM   #1
Pentaxian
littledrawe's Avatar

Join Date: Jan 2010
Location: Red Rock
Photos: Gallery | Albums
Posts: 2,434
DSLR & aperture lever arm

As I understand it, the Pentax DSLRs don't use the aperture lever arm on K & M series lenses because there is not a data pin on the lens to communicate with the body, is this correct? I think I know the answer but saw something on the forum here that made me second guess it.

12-26-2011, 12:04 PM   #2
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 40,959
They use the flappy one that sticks out to actually stop the lens down, but not the one that moves together with the aperture ring that told older cameras what it's set to.

Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com's high server and development costs are user-supported. You can help cover those costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

12-26-2011, 12:18 PM   #3
Veteran Member
jolepp's Avatar

Join Date: Oct 2010
Location: Finland
Photos: Albums
Posts: 3,196
A-type lenses and newer encode their aperture range in the connection pattern of (most of) the electrical contacts, also with them the relationship to aperture opening / lever movement was changed from what it was with K/M-lenses. The latter has been kept same since. Hence, the bodies can fully control the aperture from A-series forward: they keep the lens fully open for a bright viewfinder and stop down to what is set on the body for exposure (provided that the aperture ring is in the 'A' position, one of the contacts is dedicated for this). The body gets further information via the data pin, but it is not needed for aperture control.

edit:

see:

http://kmp.bdimitrov.de/technology/K-mount/Ka.html
http://en.wikipedia.org/wiki/Pentax_K_mount

Last edited by jolepp; 12-27-2011 at 04:47 AM. Reason: clarification + links
12-26-2011, 12:56 PM   #4
Loyal Site Supporter
Canada_Rockies's Avatar

Join Date: Nov 2007
Location: Sparwood, BC, Canada
Photos: Gallery | Albums
Posts: 9,142
If the lens does not have the automatic "A" position on the aperture ring, you must set the camera to be able to control the aperture in the menu system. Then it will stop the aperture down, but only in M - manual - exposure mode. To get the camera to select an aperture in manual mode, you press the green button (AE/L on some models I think). This will cause the camera to stop the lens down, take an exposure reading, set the shutter speed and open the aperture for focusing. There is no need to do this for every shot you take - the camera will remember the last setting for you. A more detailed description is in a sticky at the top of the beginners' forum.

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, aperture lever, arm, camera, lever, pentax help, photography
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
If the aperture blades don't move with the ring or the lever... pentaxk1000denver Pentax SLR Lens Discussion 16 12-07-2011 09:03 PM
Help: SF1/SFX: aperture lever control problem Vranx Pentax Film SLR Discussion 7 11-05-2011 02:49 PM
FA* 200/4 Macro with removed aperture lever shield. What should I ask for? Clinton Pentax SLR Lens Discussion 42 09-25-2011 09:15 PM
lens aperture lever sticks... Alizarine Pentax SLR Lens Discussion 10 08-07-2011 10:43 AM
Pentax ME Super - Aperture Lever Problem ioszhka Pentax Film SLR Discussion 9 02-10-2011 03:30 AM



All times are GMT -7. The time now is 04:47 AM. | See also: NikonForums.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