Tamron Landscape lenses for less than $500 that are 18mm or wider and have a f/2.8 or faster aperture

"I have had this lens for only a few weeks, but it's definitely become my primary lens for my D90. I really like the weight and size." bhphotovideo.com

	Min focal length	17 mm			Length	81 mm
	Aperture	f/2.8			Weight	430 g
	Image stabilization	None			Auto focus	Yes
	Diameter	74 mm			Zoom range	2.9x

"An excellent lens-especially for the price. The constant f2.8 maximum aperture makes it a first class, low light addition. It is solidly constructed and should last quite a while." bhphotovideo.com

	Min focal length	17 mm			Length	81 mm
	Aperture	f/2.8			Weight	430 g
	Image stabilization	None			Auto focus	Yes
	Diameter	74 mm			Zoom range	2.9x

"Lens has a great look to it! For the money it is beyond worth it. We use it on our 7d's and the quality is out of this world!" bhphotovideo.com

More advanced image stabilization Tamron VC

	Min focal length	17 mm			Length	94 mm
	Aperture	f/2.8			Weight	0.6 kg
	Image stabilization	Tamron VC			Auto focus	Yes
	Diameter	80 mm			Zoom range	2.9x

"The quality of the lens feels great and you come away feeling like you're getting a lot for your money. The ability to lock it into 17mm is handy for transportation and twisting it onto your body. The AF is audible but not loud enough to make it seem cheap." bhphotovideo.com

	Min focal length	17 mm			Length	81 mm
	Aperture	f/2.8			Weight	430 g
	Image stabilization	None			Auto focus	Yes
	Diameter	74 mm			Zoom range	2.9x