Originally posted by Sorver Thank you so much for your opinions on the above I have been looking at these lenses particularly the 170-500 I love photographing wildlife
I just wonder about the weight and size do you find it difficult to cart?
The short answer is yes. The 170-500 is rather bulky, although it balances quite well on my K-30. The weight is the main issue for me. It weighs about 1350g, which is almost triple my next heaviest lens! Some people are comfortable lugging around that kind of weight, but I find it a bit of a drain on a walk, especially if you add a tripod and head.
Still, to put that in perspective, the 170-500 is relatively light amongst 400mm or 500mm lens (other than mirror lenses). The Sigma 150-500 and 50-500 (the Bigma) each weigh more than 1900g (nearly half as much again). Even the Sigma 135-400 weighs about 1200g, and the 120-400 about 1700g. The well-regarded (but hard-to-find) Sigma 400 f5.6 tele-macro weighs about 1400g.
Using a lens at these long focal lengths is quite different to using, say, a 250mm or 300mm lens. They can be used handheld or with a monopod in good conditions, but generally it is better to use a tripod, keep the speed up (1/500th or faster) and stop down to at least f8 if possible. So they are best in good light.
Sorry to everyone for going off the thread topic.