Canon TS-E 24mm lens
The Canon TS-E 24 mm f/3.5L II is a tilt-shift, wide-angle prime lens that provides the equivalent of the corresponding view camera front movements on Canon EOS camera bodies. Though it uses Canon's EF lens mount, it does not provide autofocus.
The TS-E 24 mm f/3.5L II lens provides four degrees of freedom, allowing ±8.5° tilt with respect to the film or sensor plane and ±12 mm shift with respect to the center of the image area; each movement can be rotated ±90° about the lens axis.
Shifting allows adjusting the position of the subject in the image area without changing the camera angle; it is often used to avoid convergence of parallel lines, such as when photographing a tall building. Tilting the lens relies on the Scheimpflug principle to rotate the plane of focus away from parallel to the image plane; this can be used either to have all parts of an inclined subject sharply rendered, or to restrict sharpness to a small part of a scene. Tilting the lens results in a wedge-shaped depth of field that may be a better fit to some scenes than the depth of field between two parallel planes that results without tilt.
Unlike most view cameras, the shift mechanism allows shifts along only one axis, and the tilt mechanism allows tilts about only one axis; however, the rotation of the mechanisms allows the orientations of the axes to be changed, providing, in effect, combined tilt and swing, and combined rise/fall and lateral shift. In addition to optical improvements, the TS-E 24 mm f/3.5L II also introduces a new barrel design, allowing the tilt and the shift to be rotated independently of each other without removing screws on the lens body, as was required on the original version.
Known problems with: TS-E 24 mm f/3.5L II Numerous photographers have had issues with the knobs of the tilt falling off or getting into a locked state. For an unknown reason Canon can not just replace the knob and replace the entire tilt system at a large cost to the owner of the lens. 
Compare to other lens types, like standard prime lens, the amount of alternatives is very limited. Here are some alternatives:
- Nikon (only with Nikon F mount).
- Samyang (sometimes also distributed under the name Bower, Rokinon, Wallimex and other names) is a Korean company. It is providing the Tilt-Shift lens Samyang T-S 24mm f/3.5 ED AS UMC, available with Canon EF, Nikon F, Sony E, Sony A and Pentax lens mount. It is roughly 1/2 of price of this Canon lens. As TS are in general more fragile (more mechanical components like buttons and knobs) it is likely that something get broken. This is more or less valid for all TS lenses. So it is very important to have good service possibility, which seems to be not always the case for Samyang, see link.  Therefore, the lower price might end up in disaster, if no spare parts are available. 
- Schneider Kreuznach (a german manufacture) is currently providing 3 lenses with Tilt-Shift system (available Canon EF and Nikon F lens mount). One is the PC-TS SUPER-ANGULON 4.5/28, which has a similar focal length. Some of these lenses have been announced 2012, but today (2014) it is unclear if they are all available, especially the 28mm version (It is not possible to find a distributor). 
|Attribute||TS-E24mm f/ 3.5L||TS-E24mm f/3.5L II|
|feat-special||Perspective control, Scheimpflug principle|
|Focal length||24 mm|
|Aperture (max/min)||f/3.5 / f/22|
|Construction||11 elements / 9 groups||16 elements / 11 groups|
|# of diaphragm blades||8|
|Closest focusing distance||0.3 m (0.98 ft)||0.21 m (0.69 ft)|
|Max. magnification||0.14 x||0.34 x|
|Horizontal viewing angle||74° (without any tilt or shift)|
|Vertical viewing angle||53° (without any tilt or shift)|
|Diagonal viewing angle||84° (without any tilt or shift)|
|Weight||570 g (20 oz)||780 g (27.5 oz)|
|Maximum diameter||78 mm (3.1 in)||88,5 mm (3.5 in)|
|Length||86.8 mm (3.42 in)||106,9 mm (4.2 in)|
|Filter diameter||72 mm||82 mm|
|Lens cap||E-72||E-82 / E-82II|
|Release date||April 1991||June 2009|
|Currently in production?||No||Yes|
|MSRP US$||173,000 yen (w/case and hood)||250,000 yen / $2,199 (w/case and hood)|
- "Canon TS-E 24mm f/3.5L II". Canon UK. Retrieved 2010-04-05.
- "Canon strengthens tilt & shift range with two new additions" (Press release). Canon, USA. Retrieved 2009-02-18.
- "TS-E24mm f/3.5L II Tilt-Shift Lens". Canon Camera Museum. Retrieved 2010-04-04.
- "TS-E24mm f/3.5L Tilt-Shift Lens". Canon Camera Museum. Retrieved 2010-04-04.
- "Review - Canon TS-E 24 f/3.5L II". Canon Rumours. Retrieved 2014-05-26.
- "British of the Samyang T-S lens". Samyang. Retrieved 2014-09-22.
- "First look Rokinon". lensrentals. Retrieved 2014-09-22.
- "German page of the PC-TS SUPER-ANGULON (language: german)". Schneider Kreuznach. Retrieved 2014-09-22.
- "Canon TS-E 24mm f/3.5 L II Tilt-Shift Lens Review". The-Digital-Picture. Retrieved 2011-12-07.
- "TS-E 24mm f/3.5L II". Canon USA. Retrieved 2011-12-07.