Anamorphic lens

Anamorphic lenses are a type of camera lens used to capture images. A non-standard device in television and even filmmaking, they have very rarely been featured in the production of Doctor Who.

Anamorphic lenses are the key component of a process employed to produce a wider aspect ratio, initially for use with film stock, by recording a warped image which can be "de-squeezed" in post-production. In some cases, such as with the Dr. Who films' Techniscope, the anamorphic process is in fact limited to post-production, altering the dimensions of the image to conform to cinema standard formats.

Alternatively, the recording of footage with anamorphic lenses during principal photography, as during the Chris Chibnall era, entails the use of a different practice. The vertically extended frames are reconformed to the pre-intended aspect, in this case 2:1, thus restoring much of the expected geometry to the image. However, the opposite is also true: features of the image that appear perspective-correct in the initial footage become distended as a result.

The visual makeup of the final product of anamorphic footage is thus qualitatively different to imagery captured by more standard spherical lenses. Aside from distinctive features like the increasing curvature of straight lines the further they fall from the horizontal centre and vertically extended elliptical bokeh, the increased amount of glass featured in the lenses leads to the preponderance of lens flares, which in turn may be horizontally extended by post processes. Technical differences further differentiate their profiles: shallower depth of field and reduced intake of light dictate much cinematographic decision making.