Getting tired of getting Canon 24-70 2.8 L repaired

Shooting wrote in post #17923595
The green focusing square doesn't stay green very long. I read that you never take a picture with it still mag on 10, than you get the mag back to normal, by then the green square is gone and it is back to white, was that wrong? If that was wrong then no I did not shoot with the focusing on green. But it did look sharp on the lcd. I took a photo of my wife in a chair so nothing moved to change focusing plane and I had it on a tripod. I sent the lens in again but if it isn't fixed this time it is going on ebay. I did not send the camera in because it is not used on the same camera all the time. 2 weeks ago it was tested on a 50D and a 7D by another photographer with the very same results, back focusing with no recognizable face in the basketball team. Trouble is I'm still making payments on the thing.

You can shoot with the mag on 10, the camera doesn't care. Sounds to me like you are inadvertently resetting focus, and then getting focus on something else in the (much) larger green frame at 1x view.

ebiggs wrote in post #17923656
I have used the ef 24-70mm f2.8 for years and years with no issues. It has been retired now with the purchase of version II.
That old guy did about a wedding a week so it's not like it set for any time. I used it on my 1Ds Mk III, great combo.

Good for you.

Just heard from Canon, they are going to repair it (again) for free so we will see what that does. All this for backfocusing at 24mm, amazing.

Canon just asked for my camera so they can calibrate it and make it work with my camera which is good but my question is, does that mean that the lens will not work well on another camera? Because if my primary camera breaks down and I have to use it on my back up (which is the same model and make as my primary one) does that mean that it will not work well? What if I get another camera in the future? I'd have to send the lens in with that camera for another $298 adjustment?

Shooting wrote in post #17933167
Canon just asked for my camera so they can calibrate it and make it work with my camera which is good but my question is, does that mean that the lens will not work well on another camera? Because if my primary camera breaks down and I have to use it on my back up (which is the same model and make as my primary one) does that mean that it will not work well? What if I get another camera in the future? I'd have to send the lens in with that camera for another $298 adjustment?

Canon calibrates cameras using a known-accurate calibration lens. And they calibrate lenses using a known-accurate camera body.

They do NOT calibrate your lens to your body, because of the issues you raise.

So you will be good to go!

skid00skid00 wrote in post #17934052
Canon calibrates cameras using a known-accurate calibration lens. And they calibrate lenses using a known-accurate camera body.

They do NOT calibrate your lens to your body, because of the issues you raise.

So you will be good to go!

Good, thank you for that info. Got the email they are sending it them back today, they only had it one day so I guess it doesn't take long.

Got the lens and camera back today and there was a note in with the lens that said that the back element was incorrectly adjusted the first time causing rear focus and that has been corrected and the camera is performing within specifications. Preliminary testing shows it working just fine. I'll know more next Sat. when I do some bridal portraits and full length at a distance.