I have seen enough threads here on MicroAdjust so I thought I might provide some facts on it.
- Most people take hours or all day to "microadjust" a lens. Its better to send it back to Canon along with the camera or to the lens manufacturer Sigma if you have that type of lens and let them calibrate it. I think Canon charges $70, but thats a whole lot cheaper on an hourly cost basis then if you did the "microadjust" on your own. I know Sigma is good with accepting their lenses back and adjusting them. Let the experts adjust the lenses.
- Some folks who fool with the microadjust feature ultimately go back to setting it at zero when they find they have messed the focus of the camera up.
- Microadjust is useful for prime lenses only. Lets say you microadjust a zoom, then it will need different microadjust settings at different focal points. Other variables such as temperature, humidity, etc. might effect the focus adjustment too. Again, its probably best to send it to the repair depot and pay the price for calibration because it might ultimately take hours for you to do and then you mess it up.
I have two prime lenses. The Canon 50mm 1.4 seems to work well, but my Sigma 30mm 1.4 seems to have some issues. In the case of the Sigma, I plan on sending the body and lens so they can adjust it. They are the experts on these lens focus issues...I am just the photographer. I will let them fool with it versus myself in my living room taking hours to adjust the focus and even then I may not get it right.
Lets say you are a professional. Why would you want to bother with doing the calibrations yourself? You are not a person who actually inspects and works with these lenses all day long. You might spend hours trying to do this and you may even screw it up more. Why wouldnt you simply send it all back to the repair depot to get properly calibrated versus risking making the issue worse? If your bread and butter comes from wedding photography for example, why not have the experts at Canon do the calibration?
Here are reference threads to back up my conclusions:http://www.inspiring-photography.com/forum/showthread.php?t=25972http://www.flickr.com/groups/canoneos5dmarkii/discuss/72157612282515084/
This is a good link check halfway down the page. Canon states the following:http://www.northlight-images.co.uk/article_pages/cameras/1ds3_af_micoadjustment.html
"If you are attempting to set microadjustments for a zoom lens, it is important to realize that the camera's setting may only be accurate for the focal length setting you test."