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  • #31
    Re: Back Button focussing

    Currently I just half press focus and then recompose to shoot. If the exposure needs a tweak then I'll just tweak the exposure compensation. I've always done it that way from the year dot so changing will take a bit of persistence but I'll definitely give this a try. As a general question is there anything wrong with what I've always been doing?
    http://www.flickr.com/photos/flip_photo_flickr/

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    • #32
      Re: Back Button focussing

      Originally posted by TonyR View Post
      RobEW,

      Great write-up but can I just point out that the Fn1 button is the one on the right shoulder on the back of the camera whereas the button at the pivot point of the lever is called the "AEL/AFL" button.

      I'm not quite sure how that affects what you have said but I'm going to give it a try.

      I used BBF on the E-M1 for a while for C-AF but actually found it changed the way the AF worked in a bad way. To get the E-M1 C-AF to be reasonably accurate, you had to start shooting at the same time as the initial C-AF focus acquisition so AF on half press of the shutter was better. Let's hope the MkII doesn't suffer from similar issues.

      Well spotted. In fact it's a discrepancy. On the E-M1, Fn1 is on the chamfered corner near the right carrying-strap eyelet, and the button labelled AEL/AFL is in the pivot of the lever. On the E-M5 II, the button in the pivot of the two way lever is labelled Fn1 and by default is assigned to the AEL/AFL service. The E-M5 II has no button in the position of the E-M1's Fn1.

      I've corrected my post to clarify this.

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      • #33
        Re: Back Button focussing

        Originally posted by Phill D View Post
        Currently I just half press focus and then recompose to shoot. If the exposure needs a tweak then I'll just tweak the exposure compensation. I've always done it that way from the year dot so changing will take a bit of persistence but I'll definitely give this a try. As a general question is there anything wrong with what I've always been doing?
        I'm no expert, but I'd say if this works for you then it's fine. I use that method quite a lot as well. (I find focus and recompose is quicker than using the arrow keypad to move the focus point). It may need you to keep your finger on the shutter halfway down for possibly quite some time (e.g. if you're waiting for the subject to improve - e.g. for a standing bird to turn around). And if getting exact focus has been a bit painstaking and slow then you might want to retain that focus for several shots, and BBF would allow that.

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        • #34
          Re: Back Button focussing

          BBF combines well with tap-screen-to-focus for off-center subjects in street photography, especially when you want to have a small aperture (when zone focusing won't do).

          You frame the scene and tap to focus in one go, then shoot when you like including on burst mode. If the subject moves a little you can refocus immediately with BBF, and if they move a lot you just tap them on the screen again.

          If you have focusing on the half-press you have to reframe every time, which wastes ages and risks drawing the subject's attention to you.

          This is with the screen flipped out like a TLR.

          You do have to know how far from the centre the focus points spread, and in my experience tap focusing works better with the E-M1 than the M5ii, not surprisingly. Both are a bit better than the X70 Fuji (and all 3 enormously better than the A7Rii, which hasn't even got a touch screen...). I might add that the best piece of kit for doing this was my old Panasonic GM1, which focused frighteningly fast, very reliably, and in very low light, but it didn't have a tilt screen.
          Regards,
          Mark

          ------------------------------
          http://www.microcontrast.com
          Too much Oly gear.
          Panasonic GM5, 12-32, 12-35, 15. Laowa 7.5.
          Assorted legacy lenses, plus a Fuji X70 & a Sony A7S.

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          • #35
            Re: Back Button focussing

            Quick footnote-style question on this discussion. Does anyone know how BBF interacts with other ways of taking photos such as the use of the rear screen, or the use of remote shutter release cables, or - of particular interest to me - the use of the Olympus Share app on a phone to trigger the shutter. In cases like these where there is no "button half down" state, does the a last moment refocus get imposed on us whether we like it or not?

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            • #36
              Re: Back Button focussing

              Originally posted by RobEW View Post

              ...

              8. Most of the above complexity could be avoided if we could just make Fn1 toggle between MF and whatever focussing mode was previously specified. You could acquire focus either using half-pressed shutter button (or full time AF), then when it’s nicely focussed you could switch to MF, which then allows you to make fine adjustments with the focus ring (with peaking & magnification), and also prevents the shutter button from subsequently usurping control over focus.
              I was just revisiting my own write-up and realise that no-one picked up on this point.

              I've just tested, and find that if I set a button to "MF", then it actually toggles between MF and whatever focussing mode was previously in effect.

              Using this it seems easy to obtain all the benefits of back button focus with extra flexibility, fewer side effects and none of the complexities.

              I can press shutter half way down when I want to establish an autofocus and then switch to MF which will precent any later autofocus occcurring when I actually take the photo. This also gives me the opportunity to tweak the established focus using the lens ring (supported by peaking etc); the extra flexibility. If I hit the MF button again I revert easily to normal auto-focussing protocols without having to devle into menues or retrieve a MySet. No need to mess with the labyrinthine AEL/AFL modes at all.

              Are there any downsides or limitations to this method? It seems so much easier.

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              • #37
                Re: Back Button focussing

                I'm still doing this and find it more useful (for my purposes) than back button focus.

                I have Fn2 (on the E-M1 classic) set up to toggle between MF and whatever focus mode was set prior. And I have AEL/AFL set to S1/C2/M3 so that when I am in MF mode, the AEL/AFL button can be used to get an autofocus (though - being a bit of a dinosaur - I tend more often to use the manual focus ring, supported by peaking).

                Does BBF offer anything better? I suppose it offers a subset of what I do but without using the Fn2 button.

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                • #38
                  Re: Back Button focussing

                  A footnote to this. Since writing it I have obtained lenses with a AF/MF switch (PL 15 f/1.7) and with MF clutch (Oly 12 f/1.8).

                  Initially I wondered about using Fn2 for something else when one of these was mounted, but decided not to as I prefer to have a consistent meaning for my buttons irrespective of what lens is mounted. I simply ignore the extra features on the lens.

                  More recently I've obtained a (used) 12-100 f/4 and am finding it virtually never leaves the camera, so I thought I'd revisit that decision.

                  However after a bit of experimentation I have discovered that the "M3" selection (which tells the AEL/AFL button to be an AFL button when the camera is in MF mode) is ignored when the lens itself specifies MF (whether through a switch or a clutch).

                  If you want the AEL/AFL button to be usable to grab a quick auto-focus when in MF mode, then you have to specify MF mode via the camera, not via the lens.

                  So for my patterns of usage, I will continue to use Fn2 to toggle between AF and MF, and (when in MF mode) use AEL/AFL to grab a quick auto-focus. And - for my patterns of usage - any MF clutch or MF switch on a lens is not adding value.

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                  • #39
                    Re: Back Button focussing

                    I tried BBF on my mk2 programmed to the AEL/AFL button with not much success,because I found the button too stiff causing the telephoto lens to move, thus blurred images, went back to normal shutter half press pump system.

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                    • #40
                      Re: Back Button focussing

                      Sometime ago a friend set up my OMD EM 1 II for BBF, using the AEL/AFL for bbf. My question is, what settings to I need to change to revert back to the "normal" way of focussing, ie half a press of the shutter release button, with AEL/AFL returned to its usual role. Can someone help please? Thanks.

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                      • #41
                        Re: Back Button focussing

                        Gears->A1->AEL/AFL set to mode1 for either/both S-AF and or C-AF.

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                        • #42
                          Re: Back Button focussing

                          Thanks Tony, I'm very grateful for your help.

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