Through the Viewfinder (TtV) photography is a photographic or videographic technique in which a photograph or video or motion picture film is shot with one camera through the viewfinder of a second camera. The viewfinder thus acts as a kind of lens filter.[1][2][3] The most popular method involves using a digital camera as the image taking camera and an intact twin-lens reflex camera (TLR) or pseudo-TLR as the "viewfinder" camera.[4] TLRs typically have square waist-level viewfinders, with the viewfinder plane at 90 degrees to the image plane. The image in a TLR viewfinder is laterally reversed, i.e. it is a mirror image. Most photographers use a cardboard tube or other apparatus connecting the two cameras in order to eliminate stray light and prevent reflections from appearing on the viewfinder glass or on the lens of the imaging camera.
Depending on the model of TLR, the resulting image may have an old-fashioned feel to it, often with vignetting, blurred edges, distortion and dust. TLR models popular among TtV photographers have a brilliant type ('bubble glass') viewfinder. They include the Ansco Anscoflex, Argus 75, Kodak Duaflex and Kodak Brownie.