Editing Twin-lens reflex camera (section)

==Disadvantages==

Few TLR cameras offered interchangeable lenses and none were made with a [[zoom lens]]. In systems with interchangeable lenses, such as the Mamiya, the fixed distance between the lenses sets a hard limit on their size, which precludes the possibility of large aperture long-focus lenses. The lenses are also more expensive because the shutter mechanism is integrated with the lens, not the camera body, so each lens pair must include a shutter.
Because the photographer views through one lens but takes the photograph through another, [[parallax]] error makes the photograph different from the view on the screen. This difference is negligible when the subject is far away, but is critical for nearby subjects. Parallax compensation may be performed by the photographer in adjustment of the sight line while compensating for the framing change, or for highly repeatable accuracy in tabletop photography (in which the subject might be within a foot (30&nbsp;cm) of the camera), devices are available that move the camera upwards so that the taking lens goes to the exact position that the viewing lens occupied. (Mamiya's very accurate version was called the Para-mender and mounted on a tripod.) Some TLRs like the Rolleiflex (a notable early example is the Voigtländer Superb of 1933<ref>{{cite web |url=http://www.tlr-cameras.com/German/Voigtlander.html |title=Voigtlander |website=TLR Cameras Website |access-date=10 April 2018}}</ref>) also came with{{snd}} more or less complex{{snd}} devices to adjust parallax with focusing.

It is generally not possible to preview [[depth of field]], as one can with most SLRs, since the TLR's viewing lens usually has no diaphragm. Exceptions to this are the Rolleiflex, the Mamiya 105&nbsp;D and 105&nbsp;DS lenses, which have a depth-of-field preview.

As the viewfinder of a TLR camera requires the photographer to look down toward the camera, it is inconvenient to frame a photo with a subject that requires the camera to be positioned above the photographer's chest unless a tripod is used. In these cases, the camera may be positioned with the lenses oriented horizontally. Due to the TLR's square format, the composition need not be altered.
The image in the [[waist-level finder]] is reversed "left to right", which can make framing a photograph difficult, especially for an inexperienced user or with a moving subject. With high-quality TLRs like the Rolleiflex and the Mamiya C220/C330, the waist-level finder can be replaced by an eye-level finder, using a roof [[pentaprism]] or [[pentamirror]] to correct the image while making it viewable through an eyepiece at the rear of the camera.

The design of the leaf shutter limits almost all TLRs to a maximum shutter speed between 1/100 and 1/500 of a second.

Certain photographic filters are inconvenient without line of sight through the taking lens{{snd}} notably, graduated neutral density filters are hard to use with a TLR, as there is no easy way to position the filter accurately.