Yes, on an SLR, the Lens probably decides upword of about 80% of the quality if not more.

Type of lenses are as follows:

Normal Lens: A lens that has a focal length roughly equal to the diagonal of the sensor. So, on a full frame sensor that is 50mm. On a cropped sensor that is about 32mm or 35mm which is a standard size.

Wide Angle Lens: A lens that has a focal length less than a normal lens or < style="font-weight: bold;">Telephoto Lens: Focal Length >35 mm.
Good for: Portraits, brighter-light, enlarging far-off objects
What does it do: Flattens or reduces distances, shallow DOF

Zoom Lens: Allows multiple focal lengths on same lens. Can have both normal and wide-angle on same lens.
Good for: Allows more composition options on a single lens
What does it do: Multiple glass elements, quality is a generally a bit compromised, heavy, costly

Prime Lens: Only one fixed focal length
Good for: Very fast = very wide apertures (1.2f, 1.4f, 2f)
What does it do: Single lens element optimized for a single focal length, generally better quality, cheaper

Macro Lens: Designed to focus within 6 -7 inches
Good for: Small object (or Macro -- yeah weird) photography
What does it do: Produces 1-to-1 ratio of objects in frame

Fast Lens: A lens with wide aperture (1.2f, 1.4f, 2f, 2.8f) as this allows more light and hens you can shoot at relatively lower shutter speeds.

Quality and\or Costliness
  • inherent glass quality
  • Aperture or how fast a lens is (those opening wider, smaller f stops) will generally be better and more expensive)
  • Constant Aperture (generally zooms with multiple focal lengths will offer maximum apertures that are different for the range. 18-55, 3.5-4.5f: meaning at 18mm you can set the f stop max to 3.5 and at 55mm you can set the f stop to 4.5 max)
  • Zoom range