Microadjust your 7D's AF

Started Apr 8, 2011 | Discussions thread
MikeFromMesa Senior Member • Posts: 2,849
Re: Microadjust your 7D's AF

I upgraded from my T1i (500D) to my 7D about a year ago. I was most interested in the dual processors the 7D had and hoped to improve my in-focus shots. It worked, of course, but I still found some of my shots that should have been in focus were ever so slightly OOF.

I have been seeing talk of MFA in this forum since I bought the 7D and started reading the 7D postings, but never really tried it myself. I assumed the process would be difficult and did not know how I would resolve different settings for different focal lengths. But about 2 weeks ago I got tired of slightly OOF shots with some expensive lenses (Canon 100-400 and Canon 70-300 DO) and decided to try what I thought would be this useless and difficult task. What a surprise.

It took me only about 20 minutes to test all settings from -20 to +20 on each lens by focusing against an ISO 12233 chart that I found on the internet. I found that 100-400 needed a +6 (tested at 100, 150, 250, 300 and 400mm at about 12 ft) and the 70-300 needed a +5 (tested at 70, 100, 150, 200 and 300mm) at about 12 ft also). There was some variation, at the different focal lengths, but not much. I have not yet tested by Canon 15-85, but those images are usually razor sharp so perhaps there is no need.

After this I took the camera and 100-400 out of the house, saw a quail sitting on top of the neighbors house and took some shots. They were really, really sharp and I have been kicking myself for taking so long (and having so many OOF images from the past year) to get this done.

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