When is 50mm NOT 50mm?

No, not a silly question. A lot of people are confused about this.

Focal length is an absolute number. A 50mm lens is a 50mm lens, on a NEX, on a full frame camera, or on whatever camera you use it. But the field of view will change on different sized sensors. When everybody used 35mm film, they called 45-60mm a standard lens, 45mm and below a wide angle, 60-105mm a short tele and everything above a long tele. On a NEX, with a 1.5 crop factor WHEN COMPARED TO 35mm FORMAT, you need to adjust this terminology. A 50mm on a NEX can not be considered a standard lens, because it behaves like a short tele on APS-C. So on a NEX, I would consider it like this:

Wide angle: 30mm and below

Standard: 30-40mm

Short tele: 40-70mm

Long tele: 70mm or more