The answer is that for the higher price you get a constant maximum aperture of f2.8 – a fast lens for this range – and internal focus and zoom mechanisms, so the overall length of the lens is constant. You get a high speed focussing motor and superior glass. You also get a very heavy lens, which is not necessarily what anyone wants, but it is the price to be paid for the extra glass and machinery. The $289 lens is good but the $1789 lens is stunning. Sadly, camera lenses obey the fundamental law of capitalism – you get what you pay for.

Like this: This lens focusses quickly and is pin sharp, even at the maximum aperture. Resolution and contrast are excellent.

Dislike that: The tripod mount collar – which can be removed – obstructs the zoom ring and the zoom mechanism is stiff and not as smooth as the price leads us to expect.

Parting shot: This is a brilliant lens for portraiture, but its size means that you will never be able to sneak up on your subject unnoticed, even from a distance. Keep in mind that a 200mm focal length is the equivalent of 300mm when fitted to a digital camera, so it’s a good lens for getting close ups of the lions without being eaten.