Tamron 18-270mm VC Vs Nikkor AF-S 55-300mm VR?

I'm planning to buy a zoom lens. I already have a 18-55 kit lens. Above two lenses cost the same. Which one should I buy? Is Tamron optically as good as the Nikkor lens?

I would stick with the Nikkor lens!

These are two completely different lenses.

While there's not a big difference between 270mm and 300mm, almost to the point of not even being noticeable, there's a huge difference between 18 and 55mm.

Due to how optics behave (inverse square law), whenever you get beyond 2x, there will be a significant noticeable difference. Since the difference between 18 and 55mm is 3x, you will miss a lot of range with the Nikon.

However, there's more to this story.

The Tamron is known as a superzoom, as it is a 15x zoom. Any time you go over 5x or so, you start to have optical issues. Therefore, expect to have some optical aberrations with the Tamron.

In contrast, the Nikon is a 5.4x zoom, which by nature is going to be optically superior.

However, lets look at the big picture.

The Tamron is known as a super zoom, having the optical range of a wide angle to telephoto lens. The Nikon is purely a telephoto lens.

But you probably already have a 18-55mm kit lens, so between that lens and the 55-300mm lens, you will have the same range as the single Tamron lens (but optically superior as the zoom power of each individual lens is lower).

So it depends on whether or not you want to trade the convenience of a single lens vs. The quality of better optics.

I have a Nikon 18-200 zoom, which is 11x, and even it does have some blurry spots along the lens's focal length. But if used at f/8, those issues pretty much go away. It is only when used at f/5.6 and wider that these issues are noticeable.

I use this lens only as a travel lens when I'm on vacation as it is easier to carry a single lens. And I'm willing to trade optics quality for the convenience of a single lens on vacation. And since I can pretty much match my better lenses when using the 18-200 at f/8, all I'm doing in reality is restricting the lens to daylight use.

And that is fine for vacation as I normally am always taking photos in the bright sunlight.

Here is a comparison between my Nikon 18-200 vs.a Nikon 18-55 and 55-200. You will see that the two lens combo is optically superior.

http://www.althephoto.com/lenses/super-zooms.php

But since the Tamron 18-270 is even more powerful then the Nikon 18-200, I would naturally expect even worse optics. Whether or not this can be corrected by stopping down to f/8 or not, I don't have the answer. But if my less powerful Nikon 18-200 has issues, all the more likely the Tamron will too.

So to answer your question, my conclusion is that the Tamron will be optically inferior to the Nikon for two reasons; 1 - it is a higher power zoom, and generally they suffer more optically as they become more powerful, and 2 - Nikon lenses are typically a bit better to begin with.

http://www.althephoto.com

Long wide to tele zooms are almost always horrible. Especially when from third party brands.

The Nikon 55-300mm is much better quality wise, and has less problems.

Here's a Lens Buying Guide - http://www.the-dslr-photographer.com/2009/11/buying-a-lens/