Editing Twin-lens reflex camera (section)

==Advantages==
[[Image:Kodak57b.jpg|right|thumb|1957 [[Kodak]] Duaflex IV, an inexpensive fixed-focus TLR]]
A primary advantage of the TLR is in its mechanical simplicity as compared to the more common [[single-lens reflex camera]]s (SLR) cameras. The SLR must employ some method of blocking light from reaching the film during focusing, either with a [[focal plane shutter]] (most common) or with the reflex mirror itself. Both methods are mechanically complicated and add significant bulk and weight, especially in medium-format cameras.
Because of their mechanical simplicity, TLR cameras are considerably cheaper than SLR cameras of similar optical quality, as well as inherently less prone to mechanical failure.

TLRs are practically different from SLR in several respects. First, unlike virtually all film SLRs, TLRs provide a continuous image on the finder screen. The view does not black out during exposure.
Since a mirror does not need to be moved out of the way, the picture can be taken much closer to the time the shutter is actuated by the photographer, reducing so-called [[shutter lag]]. This trait, and the continuous viewing, made TLRs the preferred camera style for dance photography.<ref>{{cite web|url=http://www.arcaimaging.com/Dance_Movement_Photography.doc|title=Dance Movement Photography (DOC format)|website=arcaimaging.com|access-date=10 April 2018}}</ref>
The separate viewing lens is also very advantageous for long-exposure photographs. During exposure, an SLR's mirror must be retracted, blacking out the image in the viewfinder. A TLR's mirror is fixed and the taking lens remains open throughout the exposure, letting the photographer examine the image while the exposure is in progress. This can ease the creation of special lighting or transparency effects.
Models with leaf shutters within the lens, rather than focal-plane shutters installed inside the camera body, can synchronize with flash at higher speeds than can SLRs. Flashes on SLRs usually cannot synchronize accurately when the shutter speed is faster than 1/60th of a second and occasionally 1/125th.  Some higher quality DSLRs can synchronize at up to 1/500th of a second.  Leaf shutters allow for flash synchronization at all shutter speeds.
SLR shutter mechanisms are comparatively noisy. Most TLRs use a [[leaf shutter]] in the lens. The only mechanical noise during exposure is from the shutter leaves opening and closing.

TLRs are also ideal for candid camera shots where an eye-level camera would be conspicuous. A TLR can be hung on a neck strap and the shutter fired by [[cable release]].
Owing to the availability of [[medium-format camera]]s and the ease of image composition, the TLR was for many years also preferred by many portrait studios for static poses.

Extreme dark photographic filters like the opaque Wratten 87 can be used without problems, as they cover and thus darken only the taking lens. The image in the viewfinder stays bright.