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Old Oct 10, 2010, 8:18 PM   #1
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Default Remedial Class: Difference between AI Focus and AI Servo?

What's the difference between AI Focus and AI Servo? One Shot Focus seems straightforward - focus and hold until the button is fully depressed. I imagine this is most useful when waiting for something to pass, to avoid a fast focus situation with a slow-focusing lens.

The nuances and applications of the two AI focusing options eludes me.
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Old Oct 10, 2010, 8:47 PM   #2
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AI focus is a mix of one shot focus and AI servo. It will do exactly what one shot does, but if it detect the subject moving. It will refocus in AI servo.
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Old Oct 11, 2010, 9:59 AM   #3
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i want to say that somewhere on this forum i have read a post that discourages the use of AI Focus. Apparently a little too prone to mistakes. if i come across the post i will link it
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Old Oct 11, 2010, 10:19 AM   #4
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The problem with AI Focus is that it is guessing if you will want to have. The more I shoot and the more I learn the less I want the camera to make decisions for me. This was one of the very first areas that I moved away from. Basically if shooting normal things (people, landscapes) then I'm on single focus, if I'm shooting moving things I will switch to AI Servo (sports, wildlife).
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Old Oct 11, 2010, 11:59 AM   #5
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How do the two options behave differently?
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Old Oct 11, 2010, 12:12 PM   #6
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Quote:
Originally Posted by iowa_jim View Post
How do the two options behave differently?
Which two? AI Focus and AI Servo, or AI Servo and Single that I mention?
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Old Oct 11, 2010, 12:24 PM   #7
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AI Focus and AI Servo, please.
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Old Oct 11, 2010, 4:32 PM   #8
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Quote:
Originally Posted by iowa_jim View Post
AI Focus and AI Servo, please.
Basically what Shoturtle says, it decides if you want to be in AI Servo or One Shot. Like any auto system it does OK a lot of the time, but also it will make a mistake at times as well. I leave my camera in Single all the time unless shooting anything moving when I go to AI Servo.
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Old Oct 11, 2010, 6:55 PM   #9
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Egad, it's no wonder you don't recommend it - how can a person predict what it will do - stay focused on a fixed point or follow an object in motion. Especially with evaluative metering.
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Old Oct 12, 2010, 11:13 AM   #10
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I m with Mark on this single shot or if it moves AI servo
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