Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-20-2021, 11:16 AM   #1
New Member




Join Date: Jul 2021
Posts: 2
aperture ring

adapting inherited pentax macro lenses to my canon rebel , love them , but cannot control aperature . trimmed tab , but that does not help . The aperature seems to want to change , but hand pressure on the tab is needed . Is there any to fix this , so I can use the ring on the lens ? Thanks in advance .

07-20-2021, 11:18 AM   #2
amateur dirt farmer
Loyal Site Supporter
pepperberry farm's Avatar

Join Date: Dec 2014
Location: probably out in a field somewhere...
Photos: Gallery | Albums
Posts: 41,257
which lens are you trying to adapt?
07-20-2021, 11:35 AM   #3
Moderator
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 10,510
Trimming the tab is totally unnecessary except on most FF bodies. If the lens has an aperture ring and an "A" setting take it off "A". If there is no "A" setting then just use the aperture ring for setting.

If the lens doesn't have an aperture ring than there is no way to control the aperture except on a Pentax body. If that's the case then the lenses are pretty much useless since you trimmed the tab.

If they are screw mount lenses with an auto/manual switch set the switch to manual. Or get an adapter that would have pushed in the tab/lever.

Specifically what lenses are we talking about?
07-20-2021, 12:58 PM   #4
Otis Memorial Pentaxian
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 42,007
QuoteOriginally posted by FGolesic Quote
adapting inherited pentax macro lenses to my canon rebel , love them , but cannot control aperature . trimmed tab , but that does not help . The aperature seems to want to change , but hand pressure on the tab is needed .
Sorry you opted to trim the tab. That is often done to avoid mirror clearance issues with FF Canon models, but is not a problem for adapting. Your problem sounds strange to me in that K-mount lenses having aperture rings are stopped down as their default condition when not mounted to a camera. Unless your adapter features aperture ring emulation or similar, there is no reason for the lens to be wide open unless it is has a fault internally.


Steve

07-20-2021, 05:31 PM   #5
New Member




Join Date: Jul 2021
Posts: 2
Original Poster
QuoteOriginally posted by Not a Number Quote
Trimming the tab is totally unnecessary except on most FF bodies. If the lens has an aperture ring and an "A" setting take it off "A". If there is no "A" setting then just use the aperture ring for setting.

If the lens doesn't have an aperture ring than there is no way to control the aperture except on a Pentax body. If that's the case then the lenses are pretty much useless since you trimmed the tab.

If they are screw mount lenses with an auto/manual switch set the switch to manual. Or get an adapter that would have pushed in the tab/lever.

Specifically what lenses are we talking about?
PENTAX-F
Zoom
35-70
1:3.5-4.5
07-20-2021, 06:01 PM   #6
Otis Memorial Pentaxian
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 42,007
QuoteOriginally posted by FGolesic Quote
PENTAX-F
Zoom
35-70
1:3.5-4.5
With the lens detached from your adapter, confirm the aperture ring is not in the "A" position. Unless the mechanism has been damaged, it should be stopped down to the aperture set by the ring.


Steve
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!
aperature, k-mount, pentax lens, slr lens, tab
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Auto Aperture FAQ - changing aperture using lenses without aperture ring angerdan Film SLRs and Compact Film Cameras 11 03-11-2022 02:03 PM
Force aperture wide open in M mode without aperture ring? Igor123 Pentax DSLR Discussion 12 11-06-2016 06:32 AM
Aperture ring or no aperture ring hjoseph7 Pentax SLR Lens Discussion 29 12-02-2014 03:06 PM
K-3 and FA lenses - aperture ring setting / focus ring zzeitg Pentax K-3 & K-3 II 10 11-05-2014 08:10 PM
Use of Aperture-Ring 43mm/1.9 -> no aperture data Deimo Pentax SLR Lens Discussion 7 06-24-2009 03:25 PM



All times are GMT -7. The time now is 03:24 AM. | 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