Advantages/Disadvantages to sending in camera along with lens for calibration?

I have a 50mm 1.4 that is back focusing and Canon suggested sending it in for calibration. I am wondering if it is a good idea to also send in my camera (T4i) to optimize the calibration.

I also have an 18-135 STM and a 55-250 IS II, both of which focus accurately, but I'm wondering if sending in the camera will help/hurt how it focuses with those other lenses.

If it matters, the 50mm 1.4 is the only thing still under warranty, and the T4i is my only camera body.

Any thoughts on what would be the best course of action.

Thanks for your responses!

Have you contacted Canon yet? When I had problems they asked me to send the body and all three lenses I had at the time. One of the lenses wasn't under warranty but they were okay with that.

Be aware that there's a lot more to it than asking them to calibrate your lens. When the first-level technician tests it against the not-too-stringent standard, it'll probably pass and get sent back otherwise untouched. If you can prove there's a problem you need to ask for a supervisor and plead your case. Some of us in the 450D days had to do that four times before we got satisfaction.

CameraCarl wrote:

How do you know it is back focusing? Have you done detailed tests on a tripod to confirm this? If so and you are convinced that it is the lens, then you ought to send in the camera too, as it is the system that is giving you out of focus images. No sense in Canon determining that the lens is fine if it is the camera that is out of specification.

I followed these instructions http://regex.info/blog/photo-tech/focus-chart and until about f/8.0 the middle of the frame is soft and the sharpest point in the image is consistently a few inches behind the focus point, similar to this: http://regex.info/i/JEF_024927.jpg. I tested with a tripod, delayed timer, with & without live view, multiple shots at each aperture, and with every lens I have. Only the 50 demonstrated problems.

Thanks for the reply and suggestion!

WilbaW wrote:

Have you contacted Canon yet? When I had problems they asked me to send the body and all three lenses I had at the time. One of the lenses wasn't under warranty but they were okay with that.

Be aware that there's a lot more to it than asking them to calibrate your lens. When the first-level technician tests it against the not-too-stringent standard, it'll probably pass and get sent back otherwise untouched. If you can prove there's a problem you need to ask for a supervisor and plead your case. Some of us in the 450D days had to do that four times before we got satisfaction.

Sounds frustrating :/ . I sent images to Canon's email support and they agreed that it appeared to be problematic. I specifically asked them if there were advantages/disadvantages to sending in my camera along with the lens and they replied

The lens may require calibration to address this issue. If you wish to have the lens calibrated with your camera, you can sent the camera along with it.

I may call their support to ask about what to do with the camera body and other lenses so I don't have to wait 24 hours for email replies.

Hopefully this all goes quickly, too, because I have a baby due in February, and every dollar I have spent on this stuff has been in preparation for taking pictures of this little guy!

An excelent article on the matter:

http://www.lensrentals.com/blog/2008/12/this-lens-is-soft-and-other-myths

You have two options:

1) Send everything to Canon for calibration, including all your existing lenses - if they adjust the body the problem might start on another lens !

2) Play 'lens lottery' by exchanging untill you get a copy that works good with your camera.

Y Hafting wrote:

For the matter of the test chart, id say make sure your focus target is vertical. Focussing on something that is 45 degrees to the camera is an almost sure way to have it focus on the wrong spot.

If that something has detail up and down the slope, yes, you'll get focus on the nearest detail, but a proper focus target designed to be used that way is perfectly fine.

It is good to have a distance scale at 45 degrees or so, but the focus target should be aligned with the focus plane.

A perpendicular target is best if it's not close, and it that case you want a scale at a lower angle, seeYou Can't Test Autofocus with a Slanted Target  in Digital Photography Myths.