Sigma Lenses

I just ran across a review of the Sigma 100mm-300mm f4 and it got a great writeup. Then it seems the lens is discontinued. I am also looking at the Sigma 120mm-300mm lens 2.8.Does anyone have any knowledge on these lenses or experience with them.I am looking for a zoom in that range that is tack sharp.
Thanks for the help

The Sigma 120-300mm f2.8 is a very heavy lens and it even dwarfs the Nikon 70-200mm f2.8 lens. Hand holding it would not be advisable. Some experience slower focusing especially if you point it up when shooting birds since it it a "HEAVY" lens.

I heard again today of an issue which Sigma has had for many years. In time the lens will lose focus.Has anyone heard of this happening?

BooBoos said:

I heard again today of an issue which Sigma has had for many years. In time the lens will lose focus.Has anyone heard of this happening?

Click to expand...

Not true in my case I had one of these [120-300mm F2.8] a while back...Sharp fast lens I used for surfing and birds...