If you weren't aware, a front-focusing issue was discovered with this lens when using it at or near minimum focusing distance. Canon promised back in late Dec. they'd have a fix out in early Jan. The fix is now available.
Canon support site
From the readme:
Firmware Version 1.0.6 incorporates the following fix:
・Fixed a phenomenon when performing AF shooting to capture a subject at close-range with the focus distance approximately set to the Tele-end (200mm), the image may become slightly front-focused.
Canon support site
From the readme:
Firmware Version 1.0.6 incorporates the following fix:
・Fixed a phenomenon when performing AF shooting to capture a subject at close-range with the focus distance approximately set to the Tele-end (200mm), the image may become slightly front-focused.