Originally Posted by
Adrian
Denny - this is not really the point. We didn't have a 500mm lens at all. So when we decided to buy a long lens the field was wide open. In the context of a long term lens purchase, a relatively small extra cost for the 100mm longer reach (160mm on a Canon crop sensor) was unimportant. Based on review on camera the Tamron appeared to perform better at 500mm than the equivalent Sigma (we tried both in our local shop - they are very accommodating and let us take them away for an couple of hours- and also a much more expensive Canon) and otherwise had good reviews. In fact, unless you are being super critical, it performs well at 600mm and on say a 7D crop the extra reach (effectively making it a 960mm lens) is surprisingly useful on, for example, birds in flight.