Support for larger AE bracketing steps (550D)

Issue #189 resolved
trho created an issue


I tried out Alex's release and its working fine!

Is it possible to enable more AE Steps in bracketing mode?

I would like to have the option of 3 ev steps for 3 shots or 2 ev steps for 5 shots. Right now I get approximately 1 ev steps when I set "AE Step" to 6 and about the same for 8. Could you offer a larger range of 18 AE steps instead of 8, or change the internal step width to 1ev instead of 1/3?


Comments (20)

  1. Alex

    18 steps is easy. I don't know (yet) how to change step to 1 EV, so if you can do some detailed testing to see what those steps mean, please put the results here.

    This feature will be available in the next ML for 550D/1.0.9.

  2. trho reporter

    This was quick! ;-)

    Am looking forward to test the new range and will come back to you with the result. Currently the AEB settings are not stored in the config file. Could you please include them in the cfg, too?


  3. trho reporter

    I can confirm this. 4 and 8 steps produce 1/2 EV resp. 1 EV. In between steps (e.g. 6) seem not be be recognized at all, but rounded up. I also get 1 EV with 6 steps:

    1/45 2.8 100 +1

    1/45 2.8 200 0

    1/45 2.8 400 -1

    Keeping the available number of 8 steps and multiplying by 4 internally seems reasonable to me.

  4. trho reporter

    Another suggestion:

    Could you add an inverse operation for the set button, e.g. triggered by the display button? Working with AEB and even more changing qscale values would benefit from this. Looking at the source code this does not seem to be very complicated. Your comments on button handling issues kept me from trying it by myself ...

  5. Alex

    Inverse set: I've thought about this, and wanted to assign it to top wheel (much quicker to change the settings with many values). Wasn't able to get a reliable reading from wheel => gave up for now.

    Keeping the available number of 8 steps and multiplying by 4 internally seems reasonable to me.

    That's the best solution. Code was a bit ugly, that's why I didn't do it yet.

    If you can build the source, it will be very helpful to try and share your experiments with us. Be careful with the pointers and take the battery out quickly when you suspect something's wrong (that's what I try to do).

    Disp is easy to handle from both menu_handler (recommended) and gui_main_task_550d.

  6. trho reporter

    Is there a reason why you added msleep(1000) into the loop? I just reduced it to 100ms in it still works fine.

  7. Alex

    Bracketing is now displayed in EV (you can select 0.5 EV, 1 EV ... until 4 EV). Default is 1 EV.

    Did you have any stability problems with bracketing? It just caused a black screen here after the first picture, not sure why.

  8. trho reporter

    My patch for issue 198 also includes the reduced sleep (1000->100ms) in the bracket_task loop I mentioned earlier. You introduced the sleep in changeset 634. Did you observe any timing issues here or why did you add this msleep?

    I have done quite a number of bracketing tests today and had no issues at all.

    By the way, bracketing steps in EV units is nice! I thought about adding this, too. ;-)

  9. Alex

    Sometimes, lens_take_picture causes black screen, especially with trap focus and lcd remote sensor. It does not happen often.

  10. trho reporter

    What about distinguishing between non-lv action and lv?

    unsigned * lv;
    size_t * size;
    prop_get_value( PROP_LV_MODE, &lv, &size );
    else // even this is probably unnecessary:

    I would like to have a minimal delay here, because I often take HDR shots containing moving objects.

    A delay of 1 sec will likely spoil these shots.

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