PS: I just installed the Canon Eg-S Focusing Screen and it does help with manual focusing…BIG time!
I finally got in the Canon EOS 5D Mark II with 2 mega fast prime lenses, Smudge is the first model to pose for it. The bokeh on this fast prime lens wide open (Canon 24mm 1.4) it’s unreal…click the thumbnail to see a larger image. Stay tuned for a lot more shots with Canon 24mm 1.2 and Canon 85mm 1.2.
I still have to install the Canon precision screen EG-S which should help a lot to focus with lenses 2.8 and brighter. I can’t wait to do some aerial photography with the Canon 5D Mark II, the files are a whopping 60+MB and have lots of details! I got me the Sandisk 32GB Extreme III which will let me shoot about 1200 shots!
That said, it is true that most standard focusing screens for modern SLRs such as the EOS 5D are designed to provide a reasonable balance between viewfinder brightness and manual focusing capability. The Ee-A standard focusing screen for the EOS 5D is bright enough (and accurate enough) for manual focusing under most lighting conditions with virtually any EF lens regardless of maximum aperture. However, because of the design of the microlenses on the surface of the Ee-A, the depth of field shown through the viewfinder never appears be shallower than approximately f/2.8. Therefore, when using a lens faster than f/2.8, the depth of field in the resulting photograph may be shallower than what’s shown in the viewfinder if a working aperture larger than f/2.8 is selected. This effect can be readily seen when comparing the viewfinder image to the LCD screen during replay, if you take time to look for it.”
“If this is an issue for you, Canon offers an optional focusing screen called the Ee-S Super ( Eg-S for Canon 5DMII ) Precision Matte Screen. This focusing screen uses more powerful microlenses than the standard Ee-A screen, with the result that out-of-focus areas in the viewfinder are more accurate to the actual depth of field in the resulting image. This has the effect of making it easier to determine the exact point of focus during manual focusing, especially with high-speed lenses like the EF50mm f/1.4 USM or EF50mm f/1.2L USM. However, it also has the effect of making the Ee-S focusing screen noticeably darker than the Ee-A screen when using lenses with maximum apertures smaller than f/2.8. (No free lunch!) “