Upload & Sell: On
+1 on tolerances, as a retired mechanical engineer, I know all about tolerance cancellation and when they add.
On shimming. I just did another test and was very careful on squaring up to the fence. I tried several af, several live view and several all points. Using the left point is a waste of time because it is still too close to the center.
The results were that it was hard to find any better than the others and left right is pretty equal.
Using all points had one shot that choose the sky and tended to be more front focused. Live view was a bit better at the edges and softer at the target. This confirms my poor vision. The AF did better than my LV on the target.
All of them were more equal side to side, but much softer than the center. I am now thinking its just edge softness on this lens and that squaring up the fence is super critical.
Not sure about my other lenses. My 17TSE is sharper on the edge at f4 than this lens is at f11. Its a hard lens to test in that regard. My 24-70 f2.8 mk2 is one of the most consistent AF lenses I have ever owned. So far I have not noticed the left side issue on that lens. But I did with my 24TSE and also my 17TSE. But its hard to duplicate at home with the 17.
This tends to make me think my issue is UWA and that super careful focus is required. Deep DOF on UWA is a two edge sword. It looks close to focus over a range of focus, but it also looks best when perfect.
I need more data to believe what I just found, and I still don't have a solution when I am not shooting a fence.
Edited on Dec 07, 2012 at 09:12 PM · View previous versions