Bulb ramping with external intervalometer

[jaycmiley]

I have a DIY timelapse dolly, and I would love to be able to use it with bulb ramping. It is, however, a move shoot move system, and syncing up might be difficult with two different systems.
So what I want to have is a BRamping mode that runs off of the external focus/shutter trigger. Maybe it could read the time in between the first two shots and use that as it's delay? I would hate to have to change BRamping on the camera every time I change the delay on the dolly controller (not mx2, it's a custom one).

[a1ex]

How does the external device trigger the camera?

If it's doing a full shutter press, there's very little we can do. If you can program it to do only focus trigger (half-shutter press), it's possible. Replace the intervalometer delay condition, which reads "while (SECONDS_REMAINING > 0)", with something like "while (!get_halfshutter_pressed())" and should work.

[jaycmiley]

Luckily it is re-programmable. It is easy enough to change the interval trigger to focus. Right now its focus->shutter&focus.
It uses a 2.5mm stereo plug.

[imagecatcher]

Yep im after something like this too(mentioned a few posts earlier). My sms is a simple ic555 circuit with relay so not sw programable. Is there any signal outputs generated by the camera after a shot, a mirror lockup etc that i can use to initiate the dolly motor?(instead of a set timer that wiould go out of sync with bramping). I dont have an mx2 or nanomoco. Raspberry Pi might fit into the equation some how but i have too many there projects im learning.

[a1ex]

You can send beeps (maybe via the A/V cable) with this method: http://www.magiclantern.fm/forum/index.php?topic=1813.0

[rramirez125]

I,ve been playing with this too, and it looks like once you start the ML bulb ramp it will take the full trigger from the external device, it will just do it twice, once for the external device and once for the magic lantern trigger. is there a way to disable the intervalometer after the starting setup in ML but still allow the other to continue doing the bulb ramp trigger?

[jaycmiley]

Here's a thought
What if once the Bramp began, it didn't use an internal interval? Could it just take a picture with the right exposure (point along a curve?) when the focus was triggered externally?