I finally bit the bullet and ordered a lens align MK II which I received a few days ago. I managed to find three hours to play with it, reading the instructions online first and using the calculator to determine the minimum distance. Then, I added about 10-20% so I was using it at about 30X the focal length, 25X for the long focal lengths.
I checked my setup by using the contrast detect focus in liveview. It should result in a high percentage of perfect focus achieved.
What I quickly found is that the process is sensitive to even tiny misalignments and particularly to any tilting of the camera from side to side. The front of the ruler almost always appeared to have more blur than the rear even when perfectly focused. I believe that this comes from being too near the 25X focal length, but did not have time to confirm it. I also found it necessary to turn off IS on my old 300mm f/4 lens to stop it from drifting. The others did not drift, not even the 100-400mmL.
Most of my lenses were perfect with zero autofocus adjustment, or just needed one or two points, but two,my 24-105mm L and 85mm L needed a -10 tweaking due to backfocusing, even though the target fell within the depth of field and appeared sharp. I did all the testing with my 5D MK II, using my 17mm prime, 24-105mmL, 35mm L, 50mm f/1.4, 85mm f/1.8, 100mm f/2.8L, 135mm f/2.8L, 70-200mm f/4 L IS, 100-400mm L, and 300mm f/4L.
I mounted the lens align on a old tripod I've had for 25 years which has a geared column that came in handy for raising and lowering the target to center it vertically. I had to slide and rotate the tripod horizontally to get horizontal alignment, and that was difficult.
Some things I'd like to have to make it easier:
External lighting on the target, my lighting was bright, but not adequate to do the testing at ISO 200.
A macro type rail turned sideways would have been a excellent time saver. I have one out in my studio that I'll use next time.
A longer room. I used a hallway which allowed mt to view the target at sufficent distance for the telephotos, but my large tripod wanted more room for the legs.
I did not create any before and after photos, but I saved the final ones along with a standard focused with contrast detect (I tried manually, but could not do any better).
I'll want to take some real world images, but its cold and raining this week. We have had a cool and wet year so far in 2011.
Here is a example at 1:1 for my 35mmL and 100mmL comparing the image with contrast detect AF and the microadjusted phase detect.
100mmL with contrast detect AF
100mmL with phase detect AF (micro-adjusted)
35mmL with contrast detect AF
35mmLwith phase detect AF (micro-adjusted)
