I had a 70-200/2.8 IS for about two years that I sold recently, and I had rented the new MkII version for a bodybuilding show a couple weeks ago, and loved it! The first thing I noticed was that the lens was as sharp in the corners as in the center (or very close). This works great for full body portrait shots where before, the faces might not have been as sharp as the stomach.
Anyway, I eventually bought the lens (another copy) and went shooting yesterday, pics of my friends' dogs. Something didn't necessarily seem quite right but I couldn't put my finger on it (the lighting was brutal though).
Later, it seemed to me that maybe the right side of my pics were not as sharp or contrasty as the middle or left.
It was this quick picture that I took that made me really wonder. It's not a great example, but it's something I saw on almost all of my pics... where the DOF is sharp on the ground, it will be detailed on the left thru to the center, but then on the right it's mush. I can't find the real focus area.
I took this accidentally in single shot AF instead of servo, so focus is not on the car where it should be, but look at the ground and follow the in focus line. I can't for the life of me find it much past center on the right side.
I tried taking a picture of my friend today, portrait, with the outer AF point over her glasses. Then I took the same picture with the camera upside down (in portrait mode). This would put the left side over her face. That 2nd shot was much more contrasty and detailed. I could see pores and eyelashes on the upside down shot that I couldn't on the right side up (literally) shot.
This picture is taken in normal portrait mode (ie, right side on top) and the 2nd is taken with the camera upside down (right side down). There definitely seems to be more detail on the "left" side.
If you layer them in PS and compare say the top area, there definitely seems to be something missing from the "right" side vs the upside down shot.
I know these are pixel peeping pictures, but in just day to day shots, something seems amiss. I've heard of lens elements being out of alignment, but could this even be the case with the camera itself?
I will try to post some better samples later but any thoughts would be appreciated.
All pics taken at F2.8 using the 1D MkIII