
Originally Posted by
Arthur Morris
HI Sabya,
Hi Artie,
My responses below. I am writing point wise for the sake of clarity.
#1: Originally you wrote, "Manual of Canon super teles say don't do it," it being Focus Lock and Recompose. I still blieve that you are wrong and would need to see it in a Canon super-telephoto lens manual. (Do they have manuals or just the multi-language sheets that come with the lenses???)
I got the manual after a bit of hunting. Here, I am clearly wrong. I could not find any mention of focus lock recompose technique in the 400mm f2.8 manual. Clear case of brain malfunction I guess. :o It is a manual with the same text in various languages.
#2: In any case Chuck's statement has nothing at all to do with telephoto lenses. Note:few if any Canon super-telephoto lenses (and none of those that I use) have minimum focusing distances of less than 15 feet.
I use the 400mm F2.8 Is. It has a minimum focusing distance of 10feet. So atleast for me it is applicable.
#3: Chuck may be concerned with folks handholding their camera and lenses. At close distances it is difficult to keep your body still and if you are using One-Shot AF and small change in your or the subject's position will result in focusing errors. If you are using AI Servo AF after having chosen the ideal focusing sensor, this will result in accurate focus.
I agree with your observation. I had found AI Serve AF giving good results for my shooting so I have been using it. Your explanation helps.
#4: I am of the strong opinion that many photographers spend too much time agonizing on-line about minute technical details and issues (and poring over white papers...) and not enough time creating images and trying new techniques.