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  • Custom bracketing

    Hey guys, hope you're all well,

    I'm new here. My DAC E1 has arrived! I'm really happy with it. Mecha can handle all the moves I need, its really awesome to watch it working. =D

    But now I want to go a bit further and I've been trying some different bracketing configurations for my gear.
    I have a Sony a7RII and I was wondering if there's a way to improve its AEB range (max: 5shots 2EV or 3EV).

    To config a custom bracketing sequence with Mecha, ''M'' should run in BULB mode, is it right? I tried it, but when in bulb mode I can't find a way to get quick exposure brackets. It seems always being starting from MTR and then goes to higher exposures.

    Well, to be honest, I didn't get how ''M'' and ''E'' work properly together. =/

    I've been trying:

    (7 shots)
    M: 0.02, 0.07, 0.25, 1, 4, 16, 64
    E: 2*3

    (7 shots)
    M: -2EV
    E: 2*3

    Does anyone know if it's possible to build a 7 shots (2EV) bracket sequence starting from the quickest 1/8000 and so on... To maybe get these results?


    -6 -4 -2 MTR 2 4 6
    or
    -8 -6 -4 -2 MTR 2 4


    Now let's say if I want to go only with the Sony AEB 5shots.


    For doing that I was thinking to add ND filters to my shots, but as I'm shooting with a fisheye it's impossible to set it up. Also, in that case (if it was possible to shoot with ND) I should take 2 sequences because as I mentioned before Sony only shoots 5shots 2EV or 3EV AEB and that's not enough to get all the EV range I need, so I must take one sequence w/ ND and another without it, but in this way, I would never get a pixel perfect brackets as I realized Mecha is slightly loose on its base (H and V), then if I take out the ND manually the camera will never be in the same position as it was in the first row.

    I also made a test of 2 different bracketing sequences to get a nice range without ND:

    5shot 2V AEB _ -8 -6 -4 -2 MTR

    +

    3shot 2v AEB _ 2 4 6

    But in the end, pixels were not perfectly aligned. =(

    Can anyone help me to figure out what's the best way to get this wider EV range without shooting 2 different bracketing sequences manually?


    cheers,

    L.

  • #2
    Congrats for MECHA!

    Thanks for asking, hope you are well too.

    I'll read more thoroughly your post and might add some later,

    for now a quick answer is to use measured value for E: like 0.25 sec as 2*3 will set a progressive sequence on its own
    so please try with these values

    M: 0.02, 0.07, 0.25, 1, 4, 16, 64
    or
    M:B 0.02, 0.07, 0.25, 1, 4, 16, 64

    E: 0.25

    1 will set the position of the MTR value in sequence.

    set [ 7 IMG ]
    you just need to click/tap on [SHOOT] to test it
    1. Mecha it possible.
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    3. Mecha team up.

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    • #3
      The shortest shutter duration in bulb may be tens or hundreds of a millisecond.
      To expand the bracketing range, a smart camera controller will be needed. The up coming firmware for third party support will allow these controllers to control MECHA.

      Nick
      Fanotec
      We listen. We try harder.

      Comment


      • #4
        Thanks Dorin and Nick for your support and quick reply.

        Dorin, I tried what you suggested and I think Nick is right about the shortest exposures.
        When I shoot the IMG sequence, it seems like it's skipping the quickest shots.


        I've tried in 2 different ways: 5 IMG and 7 IMG on Bulb mode.

        When shooting 5 IMG: (M: 0.07, 0.25, 1, 4, 16 // E: 0.25) = the camera fires only 4 shots.

        When shooting 7 IMG: (M: 0.02, 0.07, 0.25, 1, 4, 16 64 // E: 0.25) , the camera fires only 5 shots.

        2 shortest exposures are being written as 1/10, although they are different. One looks underexposed than the other... maybe Sony doesn't understand what's happened while buffering/writing these shots... or maybe I'm totally lost. =/


        Now back to the whole sequence, It seems the bulb mode can't handle very fast shutter speed skipping the shortest shots, just as Nick said.


        Do you have any other suggestions for this case?


        cheers.

        Comment


        • #5
          Please set
          A:-0.5
          use custom then enter -0.5

          then try again,

          if have success, you can try to reduce to A:-0.25
          negative value on A: forces that delay after each shutter trigger, so it may allow some time for buffer or other purposes.
          1. Mecha it possible.
          2. Mecha it easy.
          3. Mecha team up.

          4. ..

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          • #6
            Dorin,

            Now it does shoot the right number of IMG. \o/

            Both A: -0.5 and A: -.0.25 works

            But there's another thing. The EV sequence is messed up.

            The first shot looks more exposed than the second one which looks the same exposure as the following 2 and all of them were written the same: 1/10

            following a screenshot of what's happening:

            What do you think?

            thanks so much for your help.
            Attached Files

            Comment


            • #7
              Where was the cable from camera plugged in
              on MECHA-DAC-H (lower one - horizontal)
              or
              on MECHA-DAC-V (upper one - vertical) ?
              1. Mecha it possible.
              2. Mecha it easy.
              3. Mecha team up.

              4. ..

              Comment


              • #8
                Plugged in H

                Comment


                • #9
                  could be some limitation of opto-coupler.

                  I'll let you know when will be an aux port accessories to try for faster shutter speed, if indeed camera allows those speeds on bulb.

                  BTW, check if your lens has pattern/template for gel filter or maybe this hack might help
                  https://www.youtube.com/watch?v=WjfTFYMPzKs

                  1. Mecha it possible.
                  2. Mecha it easy.
                  3. Mecha team up.

                  4. ..

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                  • #10
                    I did some measurements and the opto from MECHA achieve
                    effective time down to 1/1000 sec. or even 1/2000 sec.

                    but on BULB mode the camera may not manage to have that time translated in an effective exposure, unless some special mode, maybe regarding flash-sync, just a guess.., is available.
                    1. Mecha it possible.
                    2. Mecha it easy.
                    3. Mecha team up.

                    4. ..

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                    • #11
                      This is a known limitation of bulb mode in most cameras. Otherwise, many smart controllers will not have been developped.

                      Nick
                      Fanotec
                      We listen. We try harder.

                      Comment

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