What Does Nikon Nikkor. Tamron. Sigma Do? What's The Diff?

And If Someone Isn't A Prof. Photographer. Will The 18-55 Lens Be Good For Him? And After a While He Might Get A Better Lens When He Learn More About Photography.

Nikkor is the name Nikon use for their lenses - the 18-55mm is an excellent starter lens.

Sigma and Tamron (as well as Tokina) make lenses for a number of manufacturers - while largely considered inferior to the manufacturer's own lenses, the differences aren't all that great, considering their lower prices - steer clear of a second lens until you've built up some experience and have an idea of what you want it to do.