Hello Aleks94,
When recording slow motion, you need to stay at 1280 x 720 (not sure about ALL-I) in order to record all 50 frames.
When recording 30 fps or below, you should stay at 1920 x 1080 (not sure about ALL-I). ALL-I takes up more space, and is in general better quality. I don't know if ALL-I matters with raw video though. Can someone answer this?
Typically you should shoot at 1920 x 1080 (16:9), since the resolution isn't reduced. You can upscale the 720p 50fps footage to a 1080p timeline, and the quality will be better than 720p H.264 compressed.
You could shoot 50 fps at 720p, and use fps override for 24 fps, however when using fps override it is possible sound recording will stop during the recording. This isn't much of a problem if you're using an external recorder like a Zoom H5, since you can still link up the audio if some was recorded in the beginning of the clip, but when using a microphone plugged into the camera and you're relying on internal sound recording, this could be an issue.
When recording 50 fps, your shutter should be 1/100. For 24 fps, your shutter should be 1/48 (or whichever shutter speed is closest to the 180 degree rule). Basically whatever your frame rate is, double it to find out the shutter speed.
The reason your liveview is small is because you are shooting at 720p. This is correct framing. However, if you know what part of the image (top and bottom) won't be recorded, you can turn off Global Draw during raw recording. This is good because the CPU isn't as taxed while recording. So, you can have Global Draw on to see your framing, and then while recording you can see the entire image. You can also look into using an external monitor (it does have it's limitations from what I've read), or you can use a 2.5x Viewfinder and put it up to the screen, or get a magnetic frame to attach to the screen. This will help you see better what's being recording and what's in focus.
I'm not sure about the shutter. Maybe you have a shutter button setting on that shouldn't be? Try looking in the Magic Lantern Menu as well as the Canon Menu. Try using a memory card that doesn't have Magic Lantern on it to see if you can replicate the issue.
I hope this helps you out. Please post here if you have any more questions, concerns, or issues and I'll see if I can be of further assistance. Raw video is definitely worth it, so don't give up.
- Paul Harwood
