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| p.13 #12 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes |
This was a great method and seems accurate. I got solid results when tuning my 5d3 with a variety of lenses. Thank you so much for the time and energy you put forth in making a video and answering questions. If you don't mind I have a couple of additional questions.
1. In tuning my 5d3 I added a final step in order to check my results. I would use live view at 10x, and manually focus the lens until the target was crisp. Then I would press my AF back button. If the lens did not refocus I figured everything is great. The "dot-tune method" worked for several lenses. However, in using this method with a friends 7d and Sigma 50 f1.4 it would not achieve perfect focus when zoomed at 10x in live view. I would need to just touch the focus ring ever so slightly to get perfect focus. Every single time I use the camera's autofocus it would shift, the focus confirmation light would hold steady for 5 seconds, but I would still need to manually focus ever so slightly to get the chart absolutely crisp. I am assuming this is just due to the fact that the 7d AF is just slightly less accurate than the 5d3?
2. Second question. Aren't we just micro adjusting the camera's autofocus confirmation using this technique? We are basically setting up our camera to not give us a false positive confirmation that a subject is in focus, when it is not truly in focus through the lens, correct? Basically the auto focus confirmation of the camera body will not change, but will tell the lens to be in a certain position when the camera body says it is in focus? If this is correct than how can you use this method to Microadjust Manual Focus only lenses? You have also stated that you can establish critical focus using manual focus for step 2. I don't understand how that is possible if we are fine tuning the camera bodies auto focus confirmation.
Let me know if I am way off base here, I am by no means a techy, but I am usually very logical in my thinking. Thanks again.