The size and optics of Camera Lens are what make the photos look different.
Optical Zoom - is the best quality zoom, it means the lens is using the glass to zoom in. It takes a better quality photo than digital zoom.
Digital Zoom - means the photo is being cropped digitally. It looks as if it is closer up, but it is losing quality.
Portrait Lens Portrait lenses are prime lenses that do not zoom and have a large f-stop.
F-stop - Aperture - F-stop - Focal Stop are all the same thing. A great portrait lens should have a large aperture of at least f/1.8, or even better f/1.4 to achieve a blurred background or nice bokeh.
mm - 'mm' stands for millimeter, and this is the distance between your camera's sensor, and the point of convergence in the lens.
A 70 mm portrait lens makes the models face look best.
Manufacturers often make 50mm or 55 mm portraits lens so they appear closer to the human eye's perspective. Human eye perspective is 43mm.
At what mm does the models nose look smallest? Where does the model look the best? Where does the models head look distorted?
Same model taken using different mm lenses.
Telephoto Lenses / Zoom
Telephoto lens give the ability to zoom in or out and are common travel lenses. People like the convenience of not carrying a bunch of lenses with them. Zooms are larger and heavier, and often don't have as large of aperture as a prime lens.