In a statement describing the ‘phenomenon’ on the £700 650D, Canon USA warns: ‘The front rubber grips on some EOS Rebel T4i (US camera name) units produced in certain lots during the 16-day period between May 31st through June 15th 2012 may turn white after a short period of time.

UK NEWS UPDATE: Canon UK has warned of a possible allergic reaction to skin and to consult a physician if medical symptoms develop. The firm has offered a free repair service, in a programme set to start on 17 July. Canon has not disclosed the number of cameras affected but stresses that only a ‘limited number’ are impacted. No-one has so far reported an allergic reaction, anywhere in the world, according to a UK spokesman.

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‘We have determined, after enquiry with the rubber manufacturer and analysis, that the substance zinc bis (N,N’-dimethyldithiocarbamate) is what causes the rubber surface to turn white.

‘Zinc bis is not used in the production of this product. However, the quantity of rubber accelerator used in the affected production lots was slightly higher than usual.

‘As a result, the rubber grips may turn white due to a chemical reaction with the rubber accelerator and other substances.

‘High temperature and high humidity may contribute to this condition.

‘Zinc bis (N,N-dimethyldithiocarbamate), which becomes deposited on the rubber surface, is created as a result of this chemical reaction.’

Only certain serial numbers are affected. For details visit the Petapixel website and Canon USA.

A UK version of the statement is available HERE

The EOS 650D was announced last month.