Nikon 80-400 AF VR versus Sigma 150-500 HSM OS

[Gimli Glider]

I shoot with a Nikon D80. I'm looking at upgrading my zoom from a Nikon 80-400 to a Sigma 150-500 for a number of reasons.

1) Autofocus

The AF on the lens can be very slow, not very good, for example, for shooting at the local AFB or for the jet acts at airshows.

2) Softness/General Image Quality

Can be very soft at times, especially with lower apertures. Colors aren't always that great.

3) Focal Length

I'm looking for just a little bit more reach.


Would the Sigma fix any of these problems? How is the build quality and overall image quality through the zoom spectrum? Is there another lens that I should be looking at for these results (at a similar price and reach)?

Thanks!

[jetsetkiwi]

Dont Expect the auto focus or image quality to improve at all. It will be as softer than your current lens and auto focus similarly if not slower.

Also, you have to bear in mind, your losing a lot of flexability (150-500, though It might not affect where you shoot)

[Gimli Glider]

I'm not going to rule out the Sigma lens yet, but would you have any suggestions for good alternatives?