Best place to learn about Mark III custom features.

Hi.

Re- custom focus features.

Have read up on them from back to front and not really changing anything - however, on a job today I felt a couple of tweaks here or there may have helped.

As such, I am wondering if there are any sites that give a true cause and effect of what the features do/change as I can understand the canon manual to a degree but would like it explained a bit more real world if that makes sense.

Thanks in advance,

Pete.

This might help:

https://photography-on-the.net …php?p=3553659&p​ostcount=2