My 5d2 usually carries the EG-S focusing screen which is darker but makes sharpness (or lack thereof) more obvious.
My 24mm TS-E is f/3.5, whereas the focusing screen recommends going back to default with lenses smaller than f/2.8. Obviously that recommendation is kind of pulled out of thin air since whether the viewfinder is bright enough with f.5.6 or not depends on the light available. Maybe, just maybe they are concerned about low light metering not being accurate down there but then in near darkness I adjust manually anyway.
However, I found that I use my TS-E with viewfinder (as opposed to live view) quite a bit and get acceptable rates of shift adjustment out of simply using the more precise focusing screen. If I went back to the brighter screen I expect I would lose that ability and have to use live view.
On the other hand I have a manual Zeiss f/1.4 50mm which you think would greatly benefit from the precise screen. But in practice that doesn't quite work out because I have to step down the aperture manually and it it actually *is* too dark with the dark screen.
What do you TS-E people do?
