Tilt & Shift Lenses
These lenses are known as tilt shift or TS lenses, sometimes they are recorded as tilt/shift lenses or tilt-shift lenses. They are designed for single lens reflex (SLR) cameras to allow you limited control of perspective and depth of field, like you get with a view camera. View cameras give you more control, but are more expensive and heavier. There aren't too many Tilt shift lenses available for 35mm and medium format cameras. TS lenses come in different focal lengths such as 24mm, 45mm and 90mm.
They are basically medium format sized lenses mated to 35mm lens mounts which enable you to tilt and shift. Some companies produce versions of shift lenses, but not full tilt shift lenses. TS lenses are more available for medium format cameras and some companies make adapters. These types of lenses are good for shooting landscapes or architecture. Tilt Shift lenses usually cost about $1,000.