Sorry for my late response Andrew, from ML web site, here are the reasons behind it:
Most important changes in 1.2.3 since 1.1.3 (source):
- clean HDMI out
- dual monitor support
- AF at f/8 with teleconverters
- fixed an AFMA bug
- a bunch of minor fixes
Unfortunately, in order to implement the dual monitor feature, Canon made some major changes on the display side (changed some low-level registers) and LiveView implementation (which is now quad-buffered, while on 1.1.3 it's triple-buffered, just like in all other ML-enabled cameras). From ML's point of view, this resulted in the following differences:
- 1.1.3 is slightly faster when recording RAW/MLV (not much, only a few MB/s)
- fast zebras are not working on 1.2.3 or later, but they are OK on 1.1.3
- no full-screen magic zoom on 1.2.3 or later
- no brightness/contrast/saturation adjutments on 1.2.3 or later
- "DIGIC peaking" is a little more limited on 1.2.3 or later (only the basic mode is working, not the ones with fancy backgrounds)
- motion detection in "frame difference" mode does not work on 1.2.3 or later
- I'm not sure if corrupted frames are still an issue (if you experience them, try downgrading to 1.1.3)
Other than that, the two ML versions are pretty much identical.
Just for clarification. The 5DIII is not eight years old but just a tad over five. It shipped in March 2012. I took delivery of two of the first in the UK on 17th March 2012. The body only one was £2999 & the one with 24-105mm F/4L was £3689. Used a body only 5DIII is still worth £1000-1500.
I think that it's amazing that the Magic Lantern guys are still squeezing new features out of a five year old camera that is still a decent pro tool. It doesn't shoot 4K but the colours & the full frame look are still gorgeous.
Tai Klyce reacted to tigerbengal in No Joke - RAW 4K on the 5D Mark III