| Author | Thread |
|
|
06/09/2007 10:26:42 PM · #1 |
I'm off to shoot AFL footy today with my 70-200 f4 lens (kids match). Just checking on a couple of things first.
I know about the speed but I want to know about focusing.
With this lense I will be putting it in IS 2 (for panning) and lengthen the focusing distance as I doubt any shots will be close.
What I do need to know is how do you personally focus. I will be using Al-Servo but what about focusing position. Do you allow all the focusing points to be working or do you select 'one'(the centre) to work with so that you can work better (hate it when someone comes in that is close and takes the focus over to them because they hit one of the focusing points).
So, should I leave all focusing points running or select one? What do other do?
Thanks heaps.
Message edited by author 2007-06-09 22:26:58. |
|
|
|
06/09/2007 10:35:33 PM · #2 |
The only time I ever turn on all focus points is when I'm in AI Servo mode. Because in AI Servo mode, it helps the camera track the action.
|
|
|
|
06/09/2007 10:39:06 PM · #3 |
There is some interesting reading here: Canon Auto Focus Information
Specific to your question is the end of this paragraph:
AI Servo: When you put the camera into AI Servo mode, you have set the condition "The subject is definitely moving." The camera is in a "shutter priority" mode. Therefore, the camera goes into a routine that continually collects data to predict the subject movement and move the lens to intercept the subject at its new position. You can shoot even if out of focus (however, the camera cannot release the shutter if the lens is actually in motion). If you know your subject will be in constant motion, this is the best mode. If the subject is actually not moving, the chance of a misfocused shot increases as the camera goes through its data-collection routine. However, often a handheld camera does move (as the photographer sways naturally) for AI Focus to detect and correct for the sway. AI Servo will use whichever focus point you have activated. However, if you activate all the focus points, you must put the center point on the subject and half-press the shutter release for about half a second for the camera to "acquire" the right subject. After that, while you hold the shutter release, the camera can intelligently "hand off" the subject focus from point to point as the subject "wanders" over the viewscreen.
|
|
|
|
06/09/2007 11:05:02 PM · #4 |
Thanks David. That's the info I was after.
Love this site and all its help!!!!!! |
|
Home -
Challenges -
Community -
League -
Photos -
Cameras -
Lenses -
Learn -
Help -
Terms of Use -
Privacy -
Top ^
DPChallenge, and website content and design, Copyright © 2001-2025 Challenging Technologies, LLC.
All digital photo copyrights belong to the photographers and may not be used without permission.
Current Server Time: 08/30/2025 03:33:38 PM EDT.
