Originally posted by Reptilezz In my opinion the increased price of the 150-400 over the sigma 150-500 is justified 1) by being fully weather sealed and 2) by being f5.6 at 450mm. The 150-500 is f6.3 from 300mm. Being a wider aperture lens and a bit smaller, it should also be faster at focusing which is a 3rd advantage. I might upgrade to it from my 150-500 when it drops in price.
If that's all the improvement for such a big price, they can keep it.
60-250 is fixed aperture and was 60% of the price of this at launch. Acceptable for the quality. This one has to at least match it in IQ.
If I don't get a proper telephoto (300mm is too short for the uber-safe airshows we have nowadays) with good IQ I'll be [forced to] thinking seriously about a system change.