« on: March 22, 2013, 05:27:31 PM »
My 2 cents.
I have found AFMA to be important for critically sharp auto focus. I cannot depend on the viewfinder to help much. Depending on your equipment, style, and output some people may not notice the difference. For me I do. For example, my 100L macro needs +8 and that is even after Canon calibrated it. My other large aperture lenses also need AFMA to get that sharp focus which is needed on say someones eye(s) in a portrait. I think in a lot of cases the result can be greatly improved with AFMA. If you manually focus/use zoomed live view, stop down, subject is far away, etc. it may not make a noticeable difference. The point being, if I know my equipment can do something and it is not doing it then why did I spend all that money? I want to produce results that the average person could not.
PS or other sharpening techniques can mask a slightly out of focus picture. But I would prefer not to oversharpen. It will soon look unnatural.
Getting the right AFMA value can be difficult. Using a crack or other sharp contrast item helps. I found that this is a good starting point to determine how bad/good the situation is. For complete confidence then FoCal is probably the best tool there is. It can confirm your initial findings and fine tune it further. Yes it takes money and time. But I found it worth that investment.
Anyways, to each their own so if you are happy then why sweat it? Unless your curiosity is piqued. In that case take your 7d and a lens. Triopd it with say a flat dollar bill on a wall with good light at 25 to 50 times the focal length of the lens. Let it autofocus. Then zoom in and take a look. Then use AFMA and +5 and -5 to see if it gets better or worse. Let us know what you find.