i have a canon EOS 550D and i want to control it from computer. i had good result with taking photos with an ir led, arduino, and multi camera ir control library but i want to control also focus, and, if it is possible, the exposition (f number and time). i've tried to have a look but i don't understand if it is possible to control via ir led, or i have to build a remote jack simulation, or even is it is possible only with official sdk.
i even can take into account a gear system like this: http://www.instructables.com/id/Arduino-Lens-Controller-Synchronized-ZoomFocus-/
Best Answer
The official way is to use the Canon developer SDK: http://www.usa.canon.com/cusa/consumer/standard_display/sdk_homepage
You have to sign up for it but surprisingly it wasn't really a pain to do. I was working on a small photobooth project and I explained that to them and they let us in and gave us the code (no charge or verification, think I had to sign an NDA). This was a little while ago but I used it in C and then later a C# program to do remote capture, setup camera settings, do auto focus etc. It's actually pretty easy to use, and the documentation is great.
There's also an open source program called gphoto that might help you too, depending on how down and dirty you want to get. It lists your camera as supported: http://www.gphoto.org/doc/remote/
Good Luck!