It's worth it. Trying to do it manually I drove myself crazy figuring out which adjustment setting is the sharpest as the targets all look the same sharpness after a while.
Exactly my problem and I stopped using it. Always second guessing myself after the fact. I have always wanted something to tell me what was out, not me trying to figure it out.
I'm still on the fence about purchasing it. I have been sending my lenses to Canon if I thought they were out. It is not the $100.
Another thing that turned me off to MFA was there were so many methods out there. Why was someone always coming up with a better method? Canon has a method - surprisingly not in the manual so you had to hunt for it. Kinda like giving you a car manual, telling you how to change the oil but no information on what type of oil to use. You go on forums and everyone has different advice. We are working with expensive high precision equipment. Canon takes all types of measurements so it is tuned in for all focal lengths.
I'm convinced the product is solid but I'm still confused about distance. One method including Canon states 50X focal length, another states 25, one 20 to 40, one advanced, respected birder swears by minimum focus or focal point. I can't remember as it been along time since I explored this. Even the owners manual states for best results to MFA at the actual location.
I was waiting for the MAC version to come out and when it did I still held on. I have a new 70-200 2.8II that I think is a bit off. My 7D/300L F4 combo is bang on with no MFA and I use that as a benchmark. I'm debating on either sending the 70-200 to Canon or getting FoCal. I guess the latest is to choose a distance you most often shoot at?
So help me decide. Do I send the lens in which is a real pain or try FoCal? Taking advantage of the W and T range on my 5D3 is appealing. Just that distance thing is stopping me from pressing the "buy now" button.