So far in less than a year, I've personally and professionally never had problems needing F8 (but i DONT use extenders) and haven't had problems with the red dots, although if i need servo tracking, I opt for ai focus which gives me red initial illumination... For what I do, I haven't had any issues... uncompressed HD, while I am implementing video in my packages with the 5d3, I'm not doing any fancy smancy big screen stuff, just short fusion videos to add to my animoto slide shows... So meh overall, but if I ever run into the situation where I need to use extenders, then woo hoo