Bests & Worsts Reviews from Amazon

I read the other reviews of this lens and was surprised. I have been reviewing lenses for publication for 20 years now and tested this lens myself against Canon's 100-400. First, the lens is sharp and quite good out to 600mm. Before you run out and buy it let me explain a few things. AF is fast, but if you are shooting in dim lighting or focusing on something without contrast like a plain blue sky at 600mm the lens is an F6.3. This exceeds the minimum aperture of F5.6, which is what DSLRs require for minimum light and proper AF. Yes, there were some older film SLRs that could use F8 and AF properly, but today its mostly F5.6. And even at that you still need contrast for AF to work. This means you need daylight and a partially sunny condition for good AF or you may have AF hunting. Same for ANY lens with an aperture slower than F5.6. The Vibration Control is good, but hand holding this lens is not advised at longer focal lengths even with fast shutter speeds. The reason is the lens is large and not easily hand held so you often get blur, which will appear as if the lens is not sharp. As for Build quality, there are plastic parts and that is designed to keep the price down. I do not care if my lens is all metal, use of plastic and metal or carbon fiber helps keep the cost and weight down. And I take care of my lenses and do not bounce them around or hammer nails into the wall with them. If you are rough on your gear buy Canon's 600mm F4 at $13,000. or Nikon's 600mm F4 at $10,000. They are metal but also cost the price of a used car. This lens at $1.069 is a very good value. Just use common sense and consider using a Monopod or Tripod, especially from 300-600mm and your good shots will increase dramatically. And if you are in a darker area, flip the AF switch to manual focus and turn the focusing ring. Its that easy, except for those not too bright photographers who only use P-mode (Professional-mode ;-) ) and think AF is the only means to focus a lens. Those folks are known as Fauxtographers.