when you use telescope with camera you HAVEN'T magnification (nor zoom). Cameras are flatten surface, not lens.
The "apparent magnification" is resolution (image scale, arcsencod per pixel). Large sensor can "see" larger field.
To do wide field with camera (or webcam) you must use reducer.
With lens and with magnification: magnification = Fo/Fe
http://jsmastronomy.30143.n7.nabble....91/optica1.jpg
With cameras: (there isn't Fe, so there isn't magnification)
http://jsmastronomy.30143.n7.nabble....onlycamera.jpg
note:
"webcam acting like a 5mm eyepiece "
Warning: if the 5mm eyepiece has an AFOV of 80 degrees, it will show more field than an 5mm eyepiece with AFOV of 50 degrees.