Difference between Canon EOS 30D and 40D

[Am Appleton <am.appleton@xxxxxxxxxxxxx>]

According to the sales person I asked in a UK high street photography  
chain (Jessops), the difference is that as the lens on the 40D is so  
much bigger, it lets in more light. I clarified that I was was asking  
about cameras, and he reiterated, very patronisingly, that "the lens.  
It lets in more light. You get better photos because of it"

Later, I spoke to the store manager apologised for his salesman, and  
went on to explain that they weren't experts.

I am going back to my policy of using Jessops to play with the kit  
and buying it elsewhere from places who know what they are selling.

Am