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Old 09-10-2014, 07:17 PM   #3
JimThias
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Join Date: Feb 2007
Location: Grand Rapids, MI
Posts: 9,800
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Yes! Another convert.

Lalam, if you prefocus on a subject, you don't have to push the shutter button right away. The focus will not change until you push the back button again, or accidentally bump the lens. However, when the train is coming toward you, you may want to refocus at different spots in front of the train just before pressing the shutter button as you are zooming out. With a little practice, you can become very quick at that technique. I don't shoot that way very often, so most of my shots are prefocused in a particular spot on the rails where I want to capture the nose of the train at a predetermined focal length (that comes from using my 10-22 and 17-40 a lot more recently when shooting trains).

However, for moving objects that I want to continue firing on, like a football or basketball player coming toward me, I'll return the focus control to the shutter button and then change the focusing to servo mode. I do that because you never know where exactly they are going to run to, so a quick prefocus in a particular spot can prove to be a failure. A train on a fixed path is a different matter.
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Rhymes with slice, rice and mice, and probably should be spelled like "Tice."

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Last edited by JimThias; 09-10-2014 at 07:21 PM.
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