Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
10-05-2013, 09:47 AM   #1
Veteran Member
treebeard's Avatar

Join Date: Nov 2008
Location: Windham, NH
Photos: Gallery | Albums
Posts: 795
Help with Rokinon 85/1.4!

Just got this in the mail today and I really like the feel of it on my K-30. However, it won't work in "A" mode. I turn the camera on, input the focal length and I am unable to change the aperture via the dial like I can with my SMC-A 50/1.7. The only mode that it seems to work in is in Manual mode and I have to change the aperture via the lens and push the green button on my K-30. Does anyone have any advice because the few shots I took in Manual mode really impressed me. I checked the contacts on the lens and my camera but like I said my 50/1.7 works fine. Also, the aperture lever on the lens seems to move as it should when I change the aperture manually and when I put it in "A" mode it seems to move back and forth like the one on my 50/1.7.

10-05-2013, 10:00 AM   #2
Pentaxian
aurele's Avatar

Join Date: Jan 2011
Location: Paris, France
Photos: Albums
Posts: 2,958
Put the lens on F22, it should then work as a "A" lens (or on the "A" if there is one on the aperture ring).
10-05-2013, 10:17 AM   #3
Veteran Member
treebeard's Avatar

Join Date: Nov 2008
Location: Windham, NH
Photos: Gallery | Albums
Posts: 795
Original Poster
I put it on the A setting but that's a no go.perhaps I just need to clean the contacts on the lens. what should I use?
10-05-2013, 10:30 AM   #4
Pentaxian
aurele's Avatar

Join Date: Jan 2011
Location: Paris, France
Photos: Albums
Posts: 2,958
cleaning the contact is a good idea, use a solution with 80/90% alcohol in it.

10-05-2013, 11:43 AM   #5
Veteran Member
treebeard's Avatar

Join Date: Nov 2008
Location: Windham, NH
Photos: Gallery | Albums
Posts: 795
Original Poster
Will try that.
10-05-2013, 11:51 AM   #6
Pentaxian
Na Horuk's Avatar

Join Date: Feb 2012
Location: Slovenia, probably
Photos: Gallery | Albums
Posts: 10,819
Is it a new or used lens?
Is it really in A mode? You need to push the little button on the aperture ring to set it into A mode. Make sure this is set correctly before you try cleaning.
10-05-2013, 12:57 PM   #7
Veteran Member
treebeard's Avatar

Join Date: Nov 2008
Location: Windham, NH
Photos: Gallery | Albums
Posts: 795
Original Poster
I cleaned the contacts on the lens with a wipe that's 80% alcohol and everything seemed to be fine. However, now I am noticing that the lens is not really locking onto my body the way it should. If I put the lens on firmly, turn the camera on and then input the focal length it seems fine at first...but then the aperture will disappear and I get F- - - where the aperture should be. If I move the lens just slightly the aperture will flicker and then back to F - - -. It seems to be very sporadic like this. Now I am perplexed.

Last edited by treebeard; 10-05-2013 at 02:01 PM.
10-05-2013, 03:15 PM   #8
Pentaxian
carrrlangas's Avatar

Join Date: Mar 2012
Location: Cottbus (Berlin)
Photos: Gallery
Posts: 1,738
Then the problem is with the contacts. This happened to me with the FA80-320 (common failure with that lens) YouŽll need to dissasemble it and see which contact or if the plate supporting them is loose.

If you try pushing the contacts down they should return to their possition with strength (I donŽt know how to say it in english, they are spring loaded). Compare with other lens you have

10-05-2013, 03:27 PM   #9
Veteran Member
treebeard's Avatar

Join Date: Nov 2008
Location: Windham, NH
Photos: Gallery | Albums
Posts: 795
Original Poster
Will do. I really like the lens but the "locking" issue I think is throwing focus confirmation off with my K-30. When I put the lens on and it clicks like it should the focus confirmation seems to be right on, but after walking around with the lens and changing the aperture it seems to be off.
10-05-2013, 05:05 PM   #10
Pentaxian
carrrlangas's Avatar

Join Date: Mar 2012
Location: Cottbus (Berlin)
Photos: Gallery
Posts: 1,738
That is hardly related to the electrical contacts, but could have to do with a loose mount.
Oesides that it could be the phenomenom called "focus shift", related to comma and other azerrations. Look it up.
10-05-2013, 05:29 PM   #11
Veteran Member
treebeard's Avatar

Join Date: Nov 2008
Location: Windham, NH
Photos: Gallery | Albums
Posts: 795
Original Poster
I just can't seem to figure it out. Both of my other manual lenses work fine...they click snugly and
work as expected. Stepping away from it for the night. I will look it up.
10-11-2013, 05:34 AM   #12
Senior Member




Join Date: Nov 2009
Location: Newcastle, AU!
Posts: 258
Sounds like a problem with the lens imo. My Rokinon 85 and k30 work flawlessly in Av
10-11-2013, 02:37 PM   #13
Pentaxian




Join Date: Jun 2009
Location: GMT +10
Photos: Albums
Posts: 10,800
On my K-5, I have had a similar problem with a Sigma 105, but not with my Rokinon 85.

I suspect a tiny mis-alignment of the pins body to lens could be a factor sometimes. When I mount the Sigma, and firmly turn it to lock and click, I always give it a little jiggle afterwards to settle the pins, even though any possible movement is slight.
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, camera, change, k-30, k-mount, lens, mode, move, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale - Sold: Rokinon 85 mm f/1.4 lens Vantage-Point Sold Items 3 05-22-2013 04:27 PM
eBay AU: Rokinon 85/1.4 ends 21:16 AEDST russell2pi Pentax Price Watch 2 02-20-2013 01:17 PM
Wanted - Acquired: Pentax M 85 f2 or Rokinon 85 1.4 zbrueningsen Sold Items 1 09-18-2012 05:45 AM
Comparing Pentax M 85/2 to Rokinon 85/1.4 ChooseAName Pentax SLR Lens Discussion 27 08-23-2012 06:29 PM



All times are GMT -7. The time now is 08:27 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