70-200 f2.8 AF problem

[mish757]

Have a canon 70-200 f2.8 non IS lens that is having AF issues.  My other zoom lens (24-70 f2.8) is not having any issues paired with my 5D Mk III body, so pretty sure it is an issue with the 70-200.  The problem is with the AF on closer subjects (approx. within 25 ft) - on more distant subjects, the AF is tack sharp, but when I try to focus on a closer subject, the AF won't lock.  The motor continues to hunt for proper focus.  Tried cleaning the contacts, but still have the problem.  Anyone else have experience with this issue.  Thought I would ask you experts before shipping the lens off for repairs.

[mish757]

Thanks, TT.  I think you're right.  It's not that it was focusing and the image was coming out blurry, it wouldn't focus at all on the closer subjects.  When it focussed on a more distant subject, the image was sharp.

[RobertTheFat]

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@mish757 wrote:

You guys have way more knowledge about this stuff than I do.  What is AFMA?  And when you say "a lot of play in the AF connection to the focusing elements", is that something in the lens itself?  Moot points since the lens is in the mail to the Canon repair facility...just curious.

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We're just thinking out loud. You're doing what we'd probably do if we were in your shoes.

AFMA is "autofocus microadjustment". It's a method of calibrating the accuracy of the AF mechanism. Most higher-level Canon cameras have it. The Rebels don't. If your camera has it, it's described in the instruction manual.

[ebiggs1]

Robert from B Town, it ain't AFMA.  It might be a C. Func., though.

[1hiphapa]

I have almost the identical issue as mish757...a 70-200 2.8 non-IS with a 7D MKii that doesn't focus at all. 4 of my other Canon lenses work perfectly fine. I took the lens to the Canon Service Center and they tried it on a 7D and it worked, so you're right about it not being the lens. Are you aware of any common issues the 7D's have with this particular lens? I even updated the firmware to the latest version. 

[ebiggs1]

"I even updated the firmware to the latest version."

Whatever this problem is it isn't the FW.  If the lens worked on another camera, hopefully another 7D, the lens is OK.  If other lenses work on your 7D pretty much confirms the camera is OK.

You need to take both 7D and lens to the service center.  Show them what is going on with your specific gear.

[1hiphapa]

Thank you for your response! The Canon service techs used a 7D to replicate, then suggested I bring both cam & lens. I read another thread in this forum where someone suggested restoring the camera's default settings...I did and so far, that seems to have done the trick. So far. 😃

[1hiphapa]

I also have a non-IS 70-200 that wouldn't focus on a person about 20' away during a sunny day yesterday. The focus would 'hunt' but never lock. Using a 7D MKII and my 24-105, 10-22, 50mm all work fine. Almost sent it into the Canon repair facility, then decided to clear all camera settings, put the lens on today and now it's working fine. For now anyway. Maybe it's a sign of malfunctions to come or maybe clearing everything was the fix, hmm...

[ebiggs1]

"Maybe it's a sign of malfunctions to come or maybe clearing everything was the fix, hmm..."

Well here is hoping for you.  But remember the camera doesm't focus.

[1hiphapa]

understood, just seems funny how after doing that the lens for now is working perfect in either 1.5 or 3. 

[Waddizzle]

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@1hiphapawrote:

understood, just seems funny how after doing that the lens for now is working perfect in either 1.5 or 3. 

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Sometimes a hair can find its’ way onto the image sensor.  I see no reason why a hair cannot find its’ way onto the lens mount connections.