Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-23-2023, 07:55 PM   #1
Veteran Member




Join Date: Oct 2011
Location: Nebraska
Photos: Albums
Posts: 902
Rokinon 24 1.4 not registering as A mode

Hey everyone,

I just got a used Rokinon 24 1.4 used from a large camera store. I mounted it on both my K-70 and K-1 it does not read the A setting even when the aperture is placed there. This shows up F- I have pulled it off, checked the lens, cleaned the contacts, checked different cameras. I have pulled out battery for a while on the camera. To no avail. Yes it is firmly in the A position.

I really want this to work as I got a great price on it and want to do some Astro shots. It seems as though the A contact sits too low. The Mount is tight on my cameras.

Any ideas to try before I send it back?

03-23-2023, 08:17 PM   #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: 39,791
did you set the camera to use an aperture ring?
03-23-2023, 08:36 PM   #3
Pentaxian




Join Date: Oct 2011
Location: Albuquerque, NM
Posts: 6,025
QuoteOriginally posted by pepperberry farm Quote
did you set the camera to use an aperture ring?
Shouldn't need that on 'A' setting -- that setting is set to "no" by default to keep you from using lenses off the 'A' setting.


As far as ideas, try to wiggle the ring while still in A (obviously it should be locked on A, but just give it some play) and see if the F display comes to life ever, even just for a second. (If not try holding down the button and going in and out of A and see if anything happens.) If it is really completely dead, I'd just send it back. If it will display sometimes, probably some hope a minor repair/adjustment could get it working reliably.

Last edited by vonBaloney; 03-23-2023 at 08:41 PM.
03-23-2023, 08:45 PM   #4
Dan
Pentaxian




Join Date: Dec 2007
Location: Pacific Northwest
Posts: 325
QuoteOriginally posted by zbrueningsen Quote
Hey everyone,

I just got a used Rokinon 24 1.4 used from a large camera store. I mounted it on both my K-70 and K-1 it does not read the A setting even when the aperture is placed there. This shows up F- I have pulled it off, checked the lens, cleaned the contacts, checked different cameras. I have pulled out battery for a while on the camera. To no avail. Yes it is firmly in the A position.

I really want this to work as I got a great price on it and want to do some Astro shots. It seems as though the A contact sits too low. The Mount is tight on my cameras.

Any ideas to try before I send it back?
It seems like the A-pin is not extending properly on the lens. Take the lens off the camera and set the aperture ring to something other than A. Then take a look at the lens mount (on the lens). You should see a very small hole with a rounded pin just below the surface of the mount. Watch this hole while turning the aperture ring to A. As you turn the ring to the A position that small rounded pin should pop out through the hole so that it is now ABOVE the surface. When the lens is mounted on the camera that pin will touch a recessed contact on the camera's lens mount. (Only one of the electrical contacts on the camera is recessed--that's the contact for the A pin.) If the A-pin on your lens is not extending through the hole it will not touch the recessed contact and the camera will not know that the lens is in the A position.

There have been reports of a few Rokinon lenses getting stuck on the camera because of a problem with the A pin binding, in which case you have to rotate aperture ring away from the A position to retract the pin and free the lens. While this is quite rare, if it happened to the previous owner of your lens then perhaps the owner tried to fix the pin and bunged things up, so that it now doesn't work at all. Or maybe the pin mechanism was damaged when the previous owner tried to force the lens off the camera while it was stuck. In any event, a malfunctioning A-pin may help explain why you got such a great price. :-)

Dan

04-01-2023, 03:55 PM   #5
Site Supporter
Site Supporter




Join Date: Mar 2023
Location: Eastcoast Florida, Southern NJ
Posts: 9
QuoteOriginally posted by zbrueningsen Quote
Hey everyone,

I just got a used Rokinon 24 1.4 used from a large camera store. I mounted it on both my K-70 and K-1 it does not read the A setting even when the aperture is placed there. This shows up F- I have pulled it off, checked the lens, cleaned the contacts, checked different cameras. I have pulled out battery for a while on the camera. To no avail. Yes it is firmly in the A position.

I really want this to work as I got a great price on it and want to do some Astro shots. It seems as though the A contact sits too low. The Mount is tight on my cameras.

Any ideas to try before I send it back?
I'm having the same problem with a couple of A lens I'm trying to use with my new to me K1 II. I found I could get it to accept the A setting by gently rocking the lens F ring back and forth while at the A position. It will magically accept the A setting. I think it's a wear or cleaning issue with the lens. I'm going to try to deep clean the pin that sticks out of the lens to see if it might just have a little dirt in it, and it's not coming out all the way. I also found an old lens I acquired years ago somewhere that had a missing pin.
04-02-2023, 02:55 PM   #6
Pentaxian




Join Date: Oct 2011
Location: Albuquerque, NM
Posts: 6,025
Some older A lenses (like older Sigmas or Vivitars -- probably wouldn't happen with a Samyang/Rokinon) could get an invisible layer of oxidation or something on the main contact -- I fixed a couple of them just by scratching up the contact with a key to restore conductivity. (Just cleaning it didn't work -- have to essentially exfoliate the top layer of the contact).
04-02-2023, 04:43 PM   #7
Veteran Member




Join Date: Oct 2011
Location: Nebraska
Photos: Albums
Posts: 902
Original Poster
Thanks everyone. I ended up doing everything I could think of and still nothing. I applied all your suggestions. I compared the A pin of a Pentax 50 A f/2 vs the Rokinon and the Pentax pin moved freely and the Rokinon had less movement, was stiffer, and didn’t stick out near as far. Back to Adorama it went for refund. KEH had one used for about $80 more, so that’s what I ended up going with.

Thanks again! Will let you know how this one goes.

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!
camera, cameras, pentax help, photography, rokinon, troubleshooting
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Camera display not registering and some photos are blacked out stephybethk Pentax K-3 & K-3 II 3 01-26-2018 12:53 PM
? Re Metz 58-AF2 not registering lenses ... kenhreed Troubleshooting and Beginner Help 4 07-03-2014 08:57 AM
Lens not registering with camera lillymarieadams Troubleshooting and Beginner Help 5 09-26-2011 04:25 PM
Problem Registering At DPReview amir5831 General Talk 22 07-09-2007 04:18 PM



All times are GMT -7. The time now is 06:12 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