Camera and lens maker Sigma has warned photographers to beware of grey imports ? goods entering the UK through unofficial channels.

Launching a crackdown, the firm states on its website: ?What seems attractive at first glance often hides a very different story underneath. Buying goods cheaply doesn?t always mean you?re getting great value. There are hidden pitfalls many of us are unaware of.’

The firm explains that, for example, customers run the risk of missing out on Sigma UK?s extended two year warranty.

The firm warns customers not to be fooled by the lower price of grey goods, often made possible as retailers outside the UK may not include VAT.

In a downloadable document entitled Thinking About Going Grey Sigma Imaging (UK) says: ?To sum up, grey importers can only undercut legitimate retailers because of their irregular practices. Their overheads are much reduced because they have no showrooms, helplines or workshops with knowledgeable staff.

?They offer no service, support or back-up. The knock-on effect is that independent and trustworthy importers and retailers? will disappear.?

Sigma warns customers that if a customs declaration form is found to be misleading then the recipient ?may be liable to financial penalty or prosecution. Purchasers may even have to forfeit the goods?.