Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)
MQ will be fine. I would use HQ for any green screen work, VFX plates, and anything that has high level of detail that you may not want compressed too much.
Yes as Steven mentioned part of this is dependent on if what you're filming is dependent on detail (fine edges when pulling keys for VFX) and as Michael pointed out a bit of this is dependent on the resolution you're filming at.
I commonly film 6K and 5K at LQ and can't remember a time when I had a problem at that compression setting.
I've seen finished projects projected large in a theater at those resolutions and the images looked solid.
I will say though that MQ and HQ can make a nuanced difference in image quality even at 6K and 5K.
The images can be pushed to the extremes a little more (using ISO or reframing) and overall feel more robust.
If filming at 4K you might do a minimum of MQ and for shots with a large amount of fine detail (think trees in a forest) you might even consider HQ. 4K at LQ is sort of a borderline setting in terms of quality. My experience is you can get away with 4K LQ for some shoots but it does start to show some slight compression macro blocking if you look for it.
At 2K I just shoot at HQ. At that resolution the image is more prone to artifacts and is already on the soft side.
I would also only film at 2K if you absolutely need the higher frame rates.
Bear in mind you can make user presets for all of these settings (which can include the resolution, frame rate, and compression) to help quickly set your camera while on set.
At the end of the day these are just my own rule of thumb.
Test on your own to see what works for you and what you're shooting.