I'm sorry if this has been asked before. I'm about to perform AF Micro Adjustment of my lenses with my new 50D and need instructions how to do it. Page 180 in the manual is not enough. I need step by step instructions, including how how and what to photograph. Thanks!!
The first thing you need to do is find a method you like for testing focus accuracy of your camera/lens combo. There are a number of them. Then I suggest you play with it for a while. The single most important factor in setting MA is your ability to accurately determine focusing accuracy.
The OP should really have stated which lenses he was using and what focusing problems he was experiencing. Also, using the "search" facility or Google would have been a good starting point.
In my opinion (and I believe others have agreed elsewhere) the AF Microadjustment feature is a waste of time. I have a 1DMk3 and have spent hours checking out my 500 f/4, 400 f/5.6 and 100-400 zoom and convinced myself that I have improved all three lenses with varying amounts of adjustment, but in real shooting conditions this proved not to be the case and I have gone back to "0". At +20 or -20 adjustment you can make a difference, but these folk talking about +2 or -1 are just deluding themselves, IMHO.
Once you begin to photograph test targets wide open you will find all sorts of interesting variables (especially with the super speeds). It's important to calibrate your lens at the typical distance that you use it at (even Canon says so-somewhere).
Recently I took my new 50D and 24mm F1.4 lens into a small theatrical space. in the dim light waiting for the show to start I shot a test at about 20.' I could see focus was poor (after zooming in all the way with the new lucid LCD display). So I exposed several test shots, over just a few minutes, zooming in to discover that somewhere around MA "+15" was a very lot better than 0!
I didn't rush home to calibrate all my lenses on my 50D (although I have done that before with my Mk IIIs) because the next time I shoot I many have another lens or distance. Sorry, I'm sure that's not what you wanted to hear but I do believe it works.
With large DOF shots you obviously won't notice missed focused shots as much, but when shooting at minimum focus distance and thin DOF it will be clear if your MA is correct. My 400 5.6 is at +7 MA, and at zero I get no in focus shots of a subject within 100 yds. On my fast, wide angle lenses even MA of 1 or 2 make a noticeable difference at close range. However if the camera is misfocusing in ai-servo while shooting action it could make the MA feature seem irrelevant.
