melanopsin wrote in post #14446724
It has already been established in this thread that although the MKiii focus screen is not as easily switchable as MKii and Classic, it can be done with relative ease.
It has not been "established", and it isn't so.
- an -S type screen requires a different metering curve. This is in the Mark II firmware but not the Mark III.
- a split-image screen (Zeiss's recommended solution) means spot metering no longer works. Spot metering becomes even more important with fast Zeiss lenses, because like all fast lenses they have a "hot spot" in the middle (same as fall-off at the edges), but unlike fast Canons the camera firmware doesn't know to tweak the exposure for this. It is therefore very easy to miss exposure on them.
- you might like to modify a $4000 camera still under warranty; many will not.
As far as the improvements in AF confirm from the 5D Mark II to Mark III, I can't say, since I don't have either. I can say, and did over at Fred Miranda, that it always did work on the 1DS Mark III, used properly.
(On the 1DS Mark III, you look at the red box, *not* the green dot, which stays on for a fixed length of time. The red box flashes brighter. You can set it via a CF to be totally absent except when AF has been acquired, making this totally obvious. For me, this is not a good solution, because I have large hands and use AF-ON - I end up with a sore thumb.)