Walking on a street, while carrying a big camera with an equally conspicuous lens, is one of the easiest ways of attracting undue attention. When you hunch down near a puddle to capture the reflection of one of the imposing spires of Royal Courts of Justice even the most indifferent of passers-by stare at you with an expression that is a curious mix of surprise and suspicion while your girlfriend whistles an air looking elsewhere in an attempt to feign oblivion to your very existence.