The Canon T4i is the latest DSLR into the entry-level market, although a small batch of cameras seem to have been affected by a manufacturing problem. Canon has released a statement saying that the front rubber grips on some cameras may turn white after a short period of time. Canon has looked into the issue and determined that its caused by a reaction to zinc bis after exposure to high temperature or high humidity.
The company says that until suffering the issue were manufactured in a 16 day period between May 31st and June 15th. The rubber manufacturer supplying the grips seems to have used a higher rubber accelerator than normal, resulting in the chemical reaction when exposed to high temperatures or humidity. Zinc bis is also deposited on the grips as a result, which may lead to an allergic skin reaction for some users.
Canon say that they'll begin swapping out any units that suffer from the issue. To check if your camera is affected, you’ll have to consult your serial number to see if the sixth digit is 1. After you input the full serial number into Canon’s online tool, you’ll be told whether your camera is affected or not. If it is, the company will send out a free replacement in the next couple of weeks.