This is some footage I shot trying out Magic Lantern crop mode raw recording on the 5D mkII. It’s captured as a 2152x916px 1:1 crop from the 5D sensor. This gets around the aliasing problems with full frame raw mode and allows you to capture slightly higher resolution, at least it does in 2.35:1 (on the 5D mkIII I believe you can push up to 2.5K at sync speed and 3.5K for timelapse). But it introduces it’s own problems, like noise and CA being much more significant, and of course with a 1:1 crop lens resolution becomes so much more critical.
It will be a useful trick to have in the bag no doubt, handy for extreme telephoto shots on the fly or undercranking/timelapse (especially on the 5D3). And I like the gritty look the footage has, it might work well for a music video or short film. But in it’s current form (this is after all an alpha development release) it is perhaps the least user friendly system I can imagine. You can only see about 40% of what you’re filming, while you’re filming, and it’s not even the centre 40%. So for me it will remain a special usage trick, not a format I’d consider shooting a project in.
This footage was shot near Heswall boatyard on the Dee estuary at dawn, using Canon 17-40mm f4, Canon 85mm f1.8 and Nikon 80-200mm f2.8 lenses.