EF 100MM F/2 USM

This lens is very well built, it may not be fully sealed but in my opinion that's the only thing stopping this having a red ring. The lens does not move either the front or rear element for focussing which means it is naturally reluctant to attract moisture or dust internally. The proper ring-USM focuses nearly immediately, it's frighteningly sharp even wide open, the Boke and low light ability is lovely thanks to its wide aperture. What would I change? IS is obvious by its absence, but that would bump up the price and frankly is unnecessary given its wide aperture. I would probably change the aperture blades by adding one as this currently has an even number and that means half as many spikes on sunstars when stopped down... that's it. As anyone can see I'm scraping the bottom of the barrel to find anything wrong with this lens.

This really is a fine lens. It's quality is outstanding. Even at f/2 the main subject is sharp and contrasty. The usm drive is quiet and fast. It produces photos, in my opinion, nearly as good as the 135mm f/2, at 40% of the price. I can say that because I've owned both lens. Where it doeslag, as with the 85mm f/1.8, is build quality. It may preform like a L lens, but it isn't built like one. Today, with most of using digitals with ap-s size sensors,the small 85mm is often the preffed choice. But the 100mm, although never as popular, is a great lens. Perhaps one of the best portrait lens you can own.