IMO "best" comes down to cost and what you need it for.
Generally, Nikon lenses will have gone through more quality control than Sigma or tamron etc and "should" use better optics, have better AF motors etc but at a cost.
However, if you get a good copy of a Sigma or tamron lens then there will be little in it in terms of IQ.
Nikkor lenses are optically the best
I can think of several cases where this is not the case.
Nikkor lenses are optically the best
I can think of several cases where this is not the case.
When you pay a high price for an own-brand lens (Nikon, Canon, Olympus, etc) you're generally paying for one or more of:
* better (sometimes much better) build quality
* higher spec compinents, eg faster and more accurate focussing
* brand name premium
* (perhaps) better quality control
Good point. I forgot that.And Dont forget guaranteed compatibility with future cameras using the same mount.
some old sigmas etc will not work on modern DSLRs as they require rechipping.
They also make some much less good lenses. You can tell which ones these are because .... well, I expect you can see where this is going!