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E-M1 "AF-C" Back-button Focusing

Discussion in 'Olympus Cameras' started by T-Man, Sep 3, 2015.

  1. T-Man

    T-Man Mu-43 Rookie

    10
    Sep 3, 2015
    Brenham, TX
    Ted Winkle
    Hello everyone, new member here.

    I just purchased an Oly OM-D E-M1 & the 12-40 f/2.8 Pro lens this week. I haven't even unboxed everything yet.

    I'm an intermediate level enthusiast photographer with several years of shooting with Nikon FF and APS-C gear. I love my Nikon gear and plan to continue using it, but I bought into m4/3 for 2 reasons:
    1. To have a more compact, lighter "travel" camera that still provides great IQ, and
    2. The upcoming introduction of the 300mm f/4 PRO, providing 600mm equiv. in a much lighter, more convenient, less expensive package for my wildlife photography

    Anyway, my question...
    How do I setup the E-M1 for "true" AF-C back-button focusing? By that I mean D-SLR style BB focusing, where:
    -- shutter button focusing is completely deactivated, and the rear button is the sole method of activating AF
    -- shutter priority
    -- AF-C mode stays active as long as the rear button is depressed.

    I want to remove "half press" AF from the shutter button, and I want AF-C to remain full-time and continually adjust focus as long as I continue pressing the back button.

    That way, if I want AF-S, I simply depress the button and release. If I want AF-C, I press and hold the button in and follow the subject. Releasing the button locks the focus, so I don't need a separate button for focus lock. With no AF on the shutter button, the camera doesn't try to refocus on something else while I recompose and shoot. I've grown accustomed to this method with my Nikons, and I think it has the advantages of all AF methods and none of the disadvantages.

    I've searched this site and haven't found a discussion addressing all of my concerns, nor have I found an answer on an internet search. Ideally, I would like to be able to assign BB focus to the "Fn1" button, as it's in a more convenient location for me.

    Is this possible? If so, does anyone know how to do it or have a "how to" link?

    Thanks for your help!

    Ted
     
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  2. faithblinded

    faithblinded Mu-43 Top Veteran

    929
    Nov 25, 2014
    Cleveland, OH
    Ken
    custom menu A > AEL/AFL > C-AF > mode4 > OK(must hit ok to confirm setting)
    custom menu B > Fn1Function > AEL/AFL > OK(must hit ok to confirm setting)
    now exit the menu, be certain the camera is in C-AF mode, and it should operate just as you want. This is how I operate my E-M1 95% of the time.
     
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  3. faithblinded

    faithblinded Mu-43 Top Veteran

    929
    Nov 25, 2014
    Cleveland, OH
    Ken
    Ooops forgot to tell you how to turn on shutter priority.
    custom menu c > Rls Priority C > On > OK(must hit ok to confirm the setting)
     
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  4. T-Man

    T-Man Mu-43 Rookie

    10
    Sep 3, 2015
    Brenham, TX
    Ted Winkle
    Cool! Thank you so much, Ken!
    All the reading I did led me to believe it would only function as S-AF. I was getting worried that I'd have to "unlearn" long-established habits.
    I very much appreciate your assistance, sir!!!
     
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  5. Clint

    Clint Mu-43 All-Pro

    Apr 22, 2013
    San Diego area, CA
    Clint
    Welcome to the Micro 4/3s world! Once you get used to the E-M1 I think you'll really like it. For some reason it seems easy for me to move between the E-M1 and D800. Getting use to using the Lever in position 1 or 2 seemed to be key.

    One thing I have noticed with back button focusing - depending on shooting situations I get more keepers when changing the Rls Priority C to Off - typically low contrast scenes. However my default is having it set to On.
     
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  6. T-Man

    T-Man Mu-43 Rookie

    10
    Sep 3, 2015
    Brenham, TX
    Ted Winkle
    Thanks, Clint! Good info.

    Incidentally, I also have a D800, as well as D7100.
     
  7. T-Man

    T-Man Mu-43 Rookie

    10
    Sep 3, 2015
    Brenham, TX
    Ted Winkle
    BTW, Ken and Clint... I took the advice you gave me, and the BB focusing operation is behaving as I wanted, although it doesn't nail focus in dynamic situations as fast or as accurately as my Nikon DSLRs. However, it's not bad, and I can probably compensate for that limitation with technique.

    The E-M1 has some really nice features that I like, specifically the highlight and magnification feature for focus confirmation when using MF lenses. I really wish my Nikon DSLRs had that!

    Thanks again!
     
  8. newphoto1

    newphoto1 Mu-43 Regular

    87
    Aug 24, 2014
    Oklahoma
    Colin
    Not meaning to hijack your thread, but since you have an answer, I would like to expand the discussion. I have rear button focus set on my EM-1. When using the 12-40 F2.8 and focusing and releasing to re-compose, the lens will shift out of focus when I release the focus button. Mostly happens with scenics and landscapes. I often have to shift to manual focus. Any ideas?
     
  9. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    In C-AF or S-AF?
     
  10. faithblinded

    faithblinded Mu-43 Top Veteran

    929
    Nov 25, 2014
    Cleveland, OH
    Ken
    I would suggest using MF, and the scale, for shooting scapes with the 12-40. I realize it's not always ideal.
    There does seem to be a little bit more lag to things, when you assign focusing to the back button. This has been noted by others, but I never picked up on it very much, except when I'm fumbling and forgetting what to do.
    So to deal with this, first, be sure you got a focus confirmation box. Then let go of the focus button. I think this is where the camera lag is getting you. Hold on to your position a moment longer before recomposing. I feel it may not quite stop the focusing system instantaneously when using C-AF, and you release the focus button. Holding your position an extra half breath before recomposing should allow it to halt focusing completely, so that it doesn't shift when you drag the focus point across the frame while recomposing.
    That's my best guess.
     
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  11. Clint

    Clint Mu-43 All-Pro

    Apr 22, 2013
    San Diego area, CA
    Clint
    Put your focus target over the area of the screen where you'll want your focus to be.
    In the example below my focus target was just to the right of ships name, about 1/3 in from the bottom left of the photo and 1/3 into the focus area I was most concerned with.
     
    Last edited: Sep 6, 2015
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  12. Clint

    Clint Mu-43 All-Pro

    Apr 22, 2013
    San Diego area, CA
    Clint
    Shooting runners, motorcycles, or cars during races I do not notice that lag. Even with the version 3 firmware I am not confident I got the photo - until I get back and review full sized images. With my Nikons I know when I nailed it. There is still a knack to the eye, hand (and two fingers) coordination.
     
    Last edited: Sep 7, 2015
  13. newphoto1

    newphoto1 Mu-43 Regular

    87
    Aug 24, 2014
    Oklahoma
    Colin
    Thanks. Good info.
     
  14. T-Man

    T-Man Mu-43 Rookie

    10
    Sep 3, 2015
    Brenham, TX
    Ted Winkle
    Very good info, gents! Keep it coming. I'm trying to mimic a sponge here.:D

    Nice shot of the Star of India with the ship's mast in the foreground, Clint!
     
  15. T-Man

    T-Man Mu-43 Rookie

    10
    Sep 3, 2015
    Brenham, TX
    Ted Winkle
    I'm seeing the same issue, NP1, with all types of shots at all distances. I'm in C-AF.

    I like pretty much everything else about the camera and lens, but the AF performance is disappointing so far.
     
  16. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    If you don't need CAF, you can use back button focus with SAF, and it won't lose focus when releasing the button.

    Barry
     
  17. Clint

    Clint Mu-43 All-Pro

    Apr 22, 2013
    San Diego area, CA
    Clint
    The main concepts of back button focus are –

    - Locking focus and then shooting all of the images you want until you need to move the focus point – eliminates the camera having to refocus every shot

    - When set up you can hold the rear focus button and the camera continuously focuses all the while you are pressing the shutter button for photos, no delays for refocusing every shot.

    - Eliminating the need to continuously change from C-AF to S-AF. Press and hold the rear focus button and you have continuous focus – shoot away in C-AF. Let up and lock focus, take photo – repeat as needed – S-AF without changes. Now quickly need continuous focus – just hold the rear focus button for as long as you want to continuously focus and take photos – right back to C-AF without having to make a change.

    Simple and you don’t’ ever need to switch from S-AF to C-AF or back!!!

    However you have to have your thumb (at least in my case that is what is on the rear focus button, shutter finger, and mind to all sync together.

    When locking focus and recomposing you need to know your camera and actually have focus locked and your thumb totally removed from the button, before pressing the shutter button. I’m surprised on m4/3 camera people are seeing this issue as the depth of field should pretty much mask any recomposing issues from narrow depth of field. Unless shooting extremely narrow depth of field.

    And even if there is extreme narrow depth of field, the means to resolve is to move the focusing target to the vicinity you want focused with the rest of subject framed as you want, so when you do have lock focus you do not need to recompose. This is my preferred method all of time.

    In the photo above both ships were moving up or down 3-6 feet and the speeds were not constant nor consistent so I was waiting and concentrating on the best framing I could get. I let the camera keep focus someplace around the ships name. When I knew my framing was not going to get any better I think I fired off three frames, let up on the focus button, refocused and only got one more frame before the bow of the Star was now behind lines on the America – right where I did not want them!
     
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  18. Clint

    Clint Mu-43 All-Pro

    Apr 22, 2013
    San Diego area, CA
    Clint
    The Olympus focus system is unlike Nikons. I ended up taking my Olympus out and purposely tried to fool the focus when using a single focusing target into not being able to lock focus. What I learned form that has help significantly in me getting focus 99.99% of the even the worst situations.

    Although not to level of the D800, and could make a damn fine showing in a challenge.
     
  19. newphoto1

    newphoto1 Mu-43 Regular

    87
    Aug 24, 2014
    Oklahoma
    Colin
    Just to clarify, I am removing my finger completely from the back button before recomposing. My lens doesn't just shift slightly, it goes clear out of focus. The only solution I have found is to switch to manual focus for landscapes. Doesn't seem to be a problem if not focusing at infinity???
     
  20. Ross the fiddler

    Ross the fiddler Mu-43 Hall of Famer

    My solution for using 'back button' AF is when in MF the AEL/AFL button is set to AF, but in other AF modes it is set to AEL Spot Metering, but I was never a Nikon user though.