Hi there,I tried the EG-S screen in my 5DII. I personally didn't like it. It was ok with my fast primes but not with the 24-105.I haven't tried any of the custom solutions yet and would be concerned about the metering being thrown off. I put the factory screen back in and decided to live with it. Any time I pick up my AE-1p with its beautiful large and bright screen and split prism I can only shake my head and wonder why nobody has figured this out for modern DSLRs yet.
If anyone can recommend a magnifier that'd be awesome, and it would make the split image much more powerful.Also, does anyone happen to know what the default screen is for the 5D3? Apparently, it's really easy to manually focus out-of-box.