Lens of the week . . .: . . . and why it calls for discretion when one frolics with one's financial adviser

FROM 200 yards away, a good photographer can capture the small print on a magazine cover. From 600 yards, he can reveal the freckles on a model's face. But from half a mile away, he can land a duchess in lots of hot water.

As the pictures above demonstrate, modern photographic techniques leave little to the imagination. In the hands of an experienced paparazzo, a 1,600mm telephoto lens produces images of startling clarity.

Only Daniel Angeli, the photographer who recorded the Duchess of York's poolside frolics, knows how far he was from the action when he took the pictures which were published across the world last week. According to some accounts, he must have hidden in bushes only 70 yards away to achieve an uninterrupted line of sight.

These pictures of a model in Hyde Park, however, suggest that, as claimed, the photographer could have been a comfortable distance away and outside the grounds of the villa in the south of France which was rented by the duchess and her financial adviser, John Bryan.

Angeli's photographs were probably taken with an 800mm lens, coupled to a two-times converter to boost its power to 1,600mm, from about 800 yards. The images were then enlarged in the darkroom, accounting for the fuzziness in many of the pictures published in the Daily Mirror.

The secluded five-bedroom villa near St Tropez is surrounded by woods and, according to some estimates, Angeli would have had to hack his way a mile and a half through dense undergrowth to come close to the poolside.

Lenses of the type used by Angeli have been available since the advent of the single lens reflex (SLR) camera in the Fifties. They do not come cheap. An 800mm lens with converter costs about pounds 3,500. Carrying one could prove even more expensive in osteopath's bills: they are nearly three feet long and weigh 14lb. Angeli, like Mr Bryan, probably needs a neck massage.

(Photograph omitted)