External Cameras - Capture Images from DSLR!

Since I'm waiting for feedback on the latest release candidate, I've had some time to look at a great new feature:  External Camera Triggers.  Now I've got something working!  

In the devel branch of Octolapse (requires OctoPrint 1.3.9rc3 or above), there is a new option in the camera profiles called 'Camera Type'.  The default is webcam, but there is another option:  External Camera - Script.

The new option will execute a script located in the option 'Snapshot Acquire Script' camera setting (available with the external camera type) right after Octolapse stabilized the printer.  It will wait for the script to complete before continuing, and will apply a camera delay AFTER the script has executed.  I find that I need no delay at all with my camera.

I pass lots of useful arguments into the script, and will end up passing even more, but here is the current list (in order):   Snapshot Number, Delay Seconds, Data Directory, Download Directory, Download Filename,  Download Full Path. 

Let me know if there is additional info that I should pass into the script!

I was able to create a windows batch and a Linux bash script that takes and downloads an image from my DSLR and moves it into the proper folder for Octolapse.  This way Octolapse will even render the resulting timelapse!  Of course you could always disable rendering and turn snapshot cleaning off to render the timelapse yourself

For windows I'm using CameraControlCmd.exe from digiCamControl to capture and download an image from my DSLR.  It is a free program with an easy-to-use command line interface. 

For Linux I'm using GPhoto2 , which works great, but gave me lots of installation troubles on my pi.  Eventually I got it working :)  It's a nice piece of software, and I'm sure it won't be a problem to install for people more comfortable with Linux than I am.

I think it would be possible to trigger a camera from the GPIO using this method too, but I haven't tried it.  If not I may add this ability to Octolapse in a future version.

What do you all think?  I have copies of my windows and Linux scripts if any gurus would like to look them over.  Or maybe you could send me your scripts!  I may even include some default scripts when this feature is ready.