"35mm" refers to the width of the film (actual dimensions are 36x24 mm, but the name comes from video, which was actually 35mm). For comparison, there are other sized films, the most famous being APS film, which was a bit smaller at 24mm wide. Digital cameras replace the film for electronic sensors.
What is the standard lens for a 35mm camera?
For a 35 mm camera with a diagonal of 43 mm, the most commonly used normal lens is 50 mm, but focal lengths between about 40 and 58 mm are also considered normal. The 50 mm focal length was chosen by Oskar Barnack, the creator of the Leica camera.
What does 35mm full frame mean?
A full-frame camera uses a sensor that's the same size as a single frame of traditional 35mm film, measuring 36 x 24mm. The more popular APS-C sensor size found in most DSLRs and mirrorless cameras measures 22 x 15mm. This means a full-frame sensor has more than 2.5 times the surface area of an APS-C sensor.