Hi,
I see several improvements that could be done to have a more complete video mode in 500D (from easiest to hardest):
1)Allow to change aperture without needing to go physical through all values ( to go from 2 to 3 you need to go through 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9).
2)Av Semi-automatic exposure before shooting the scene and lock it for the scene.
3)Av Semi-automatic exposure dynamic and adjusting smoothly while filming.
4) Make canon auto-focus remotely controlled/triggered (useful for selfie video).
5) Display focus indicator (a number) while recording to assist manual focus.
6) Have a user-guided follow object auto-focus mode (user specifies direction with keys, the machine goes in that direction as much as necessary for focus).
7)Find a way to get full HD@24 fps (maybe using jepg re-compressed raw)
I'm a developer and I will try to see theses things.
If you have any thought on that It would be welcome! :)
[Edit:] 1,2,3 are done: https://www.magiclantern.fm/forum/index.php?topic=20878.0