06-26-2014, 06:33 PM
"Level of improvement" is depending very much on what you want to get as pictures.
Why do you want to upgrade, are there things you can't do with the kit lens?
The Sigma has OS (=VR) and is a faster (and heavier) lens than the kit. It's very sharp and I found it very useful. But then, there are primes which are even faster and not that expensive: 50/1.8, 35/1.8
But that all depends on what you want to do or at least which kind of improvement you expect.
Why do you want to upgrade, are there things you can't do with the kit lens?
The Sigma has OS (=VR) and is a faster (and heavier) lens than the kit. It's very sharp and I found it very useful. But then, there are primes which are even faster and not that expensive: 50/1.8, 35/1.8
But that all depends on what you want to do or at least which kind of improvement you expect.