Auto-focus problem

[tsingi]

my Canon 70-200mm F2.8 USM lens and the lens wont auto focus. It focus for the first shot and then struggles to focus ...

When I hold the shoot button half way, the lens is just focusing back and forth, and not finding anything to focus on.

Manual focus works perfectly tho, I bought it used online and i barely used it

[ebiggs1]

Could be too close or too dark or it's broken.  Could be several things but you need to be more clear about how you used it and on what camera. What conditions? As much info as you can give.

[RobertTheFat]

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@ebiggs1 wrote:

Could be too close or too dark or it's broken.  Could be several things but you need to be more clear about how you used it and on what camera. What conditions? As much info as you can give.

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And if you have a Canon flash unit, make sure that "AF Assist Beam" is turned on.

[Waddizzle]

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@tsingi wrote:
my Canon 70-200mm F2.8 USM lens and the lens wont auto focus. It focus for the first shot and then struggles to focus ...

When I hold the shoot button half way, the lens is just focusing back and forth, and not finding anything to focus on.

Manual focus works perfectly tho, I bought it used online and i barely used it

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If the lens cannot focus outdoors on a sunny day on something 20 feet away, then the lens is likely faulty.

[tsingi]

The lens was shooting perfect during events, and even close-up shoots but now it doesn’t get a focus

[Waddizzle]

It needs service.