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

acmatunl wrote:

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!

Ill add that the 50mm 1.4 i have is showing different need for calibration at different distances with my 6D. I did not perform any thorough test on the 30D five years ago, so i do not know if it is something that has happened over time, or if the lens just is this way by design. Currently i have 0 MFA at infinity, while close up some -10 to -20 would be better depending on the distance.

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

If i were you id do some comparison at infinity and closer range before calibration of the 50mm 1.4. (please tell if you do)

But then for the sake of calibration id send in everything and tell that the other lenses seem to work fine with the camera, but if it is the camera that needs adjustment it would be good if they could check the other lenses too. It is likely that they will only adjust the 50mm to your camera, but in the event everything needs adjustment you will get it done within a reasonable amount of time.

Good luck!

-Yngve