I just got myself external HDMI LCD. Well, literally LCD - this one is bare 7" 800x480 LCD + controller board with HDMI, VGA and Composite inputs. It handles inputs like 1920x1080 without problem, just downscale image to fit native resolution.
Exactly, this one: http://www.ebay.com/itm/221549723168 I got case from some old analog car lcd (7" 480x272) that has exactly same dimensions, so external lcd for 40 bucks seems like a very good deal.
But going back on topic. I connected it to my 550d. Everything's fine with one small exception - image on LCD is 3:2, like on camera internal LCD. Switching layout to 16:9/16:10 in ML menu (i use nightly from about a month ago) changes only position of elements inside that 3:2 part.
Does it work like this by design, and I should be able to "crop" image inside monitor, or camera is detecting LCD improperly?
That's how it looks on LCD:
(http://galeria.kitor.pl/unsorted/ml_lcd/1.jpg) (http://galeria.kitor.pl/unsorted/ml_lcd/2.jpg) (http://galeria.kitor.pl/unsorted/ml_lcd/3.jpg)
This is the correct behavior as designed by canon, magic lantern cannot change this. You will want to use a monitor that can scale the image to fill the screen, then the display controls in ML will allow you to place the overlays higher so you can see them after the crop
That's the answer I wanted, thanks :)
For RTD2660, uC that sits on this board, there exists... open source firmware. So there's a chance for this option in future ;)