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What is the focus ring used for on a Oly 12mm?

Discussion in 'Native Lenses' started by slackercruster, Jul 22, 2012.

  1. slackercruster

    slackercruster Mu-43 Regular

    Jul 18, 2012
    NE US
    Bot a used 12mm. No instructions with the lens. Does the focus ring do anything? Just looks to spin freely either way?

  2. spatulaboy

    spatulaboy I'm not really here Subscribing Member

    Jul 13, 2011
    North Carolina
    Manual focusing.
  3. Sammyboy

    Sammyboy m43 Pro

    Oct 26, 2010
    Steeler Country
    • Like Like x 1
  4. 0dBm

    0dBm Mu-43 Top Veteran

    Jun 30, 2011
    Western United States
    When in auto focus mode (ring fully forward towards the lens front glass element) it spins freely and has little or no function. When in manual focus mode (ring fully rearward towards the rear lens glass element), it serves as the focusing mechanism.

    I use it for focusing when I shoot video.
    • Like Like x 1
  5. RT_Panther

    RT_Panther Mu-43 Legend

    May 4, 2011
  6. slackercruster

    slackercruster Mu-43 Regular

    Jul 18, 2012
    NE US
    Thanks guys!

    Without forums I'd be sunk!
  7. hkpzee

    hkpzee Mu-43 All-Pro

    Sep 5, 2011
    Hong Kong
    :confused: :confused: :confused: 

    BTW, if you pull back the focusing ring, it immediately shifts to manual focus. This is a unique feature among all Oly m4/3 lenses... :wink:
  8. WT21

    WT21 Super Moderator Subscribing Member

    Feb 19, 2010
    Even without pulling it back, you should still be able to MF if you set the camera to MF (I believe -- I had a 12mm about a year ago, but I don't remember it that well).
  9. hkpzee

    hkpzee Mu-43 All-Pro

    Sep 5, 2011
    Hong Kong
    That is absolutely correct!
  10. Ray Sachs

    Ray Sachs Super Moderator Subscribing Member

    Apr 17, 2010
    Near Philadephila
    Yeah, but the behavior is different. When its in AF position but you set the camera to MF, it feels like any other focus by wire lens but this is where its best for highly precise critical focus tasks - the manual focus mechanism it totally linear and smooth. When you pull the focus ring back, it automatically puts the camera in MF mode and it feel totally unlike a by-wire focussing mechanism and feels very much like a classic old manual focus lens. And in this mode, with the various focus distance markings on the ring, its absolutely perfect for zone focus and hyperfocal shooting and adjusting focus quickly.


    In this pulled back mode, the focus ring, as good as it FEELS, is much less precise and linear. There's a series of little "jumps" as it moves through the focus range that its hard to see but if you magnify the view and turn the ring very slowly are quite obvious. There are discrete steps as opposed to a step-less smooth transition through the range of distances. As such, its actually NOT very good for critical focus tasks. So, bottom line, the focus ring is great for moving between different zones in a zone focus situation or for finding the hyperfocal distance - its great for quick on the fly changes. But its not nearly as precise as the focus mechanism is when left in "by wire" configuration.

    I use this lens the vast majority of the time for zone focus, with occasional clicks back to AF, so its perfect for me, but the "snap" mechanism that puts it in manual focus mode is not the best way to get there for all situations.

    • Like Like x 2
  11. htc

    htc Mu-43 Top Veteran

    Jan 11, 2011
    And while this seems stupid, after awhile you KNOW by experience, that when the ring is pulled back accidentally, it doesn't autofocus ;-) Been there done that!
  12. hkpzee

    hkpzee Mu-43 All-Pro

    Sep 5, 2011
    Hong Kong
    Yeah, that happened to me also! :redface:
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