Raskill wrote:moz wrote:Sigma 120-300/2.8 <cough> with a TC.
Theres nothing wrong with this lens, let me assure you.
My objection to it is the unfortunate name, hence the <cough>. It physically cannot give you f/2.8 at 300mm as the front element is not big enough. 300/2.8=107mm, with a 105mm front element. Given edge losses, I think 100mm is a fair call for the biggest effective front aperture. The Canon 300/2.8 is 128mm diameter on the outside where the Sigma is 112mm.
Personally, I wouldn't buy one because it doesn't suit my shooting style. If it has IS (not OS) then I would quite probably own one already, but without that I think it would be unusable too often to be worth carrying around. But for people who use tripods or high shutter speeds, it's a brilliant lens. I was quite disappointed to discover that I couldn't use it when I tried it.