A medium telephoto lens is a lens between 85mm and 200mm.
The first lens you should purchase to take wildlife photographs with is a medium telephoto lens. If your budget allows, buy a lens that is fast, i.e. f2.8 or f4. With a fast lens, you can use a 1.4x or 2x tele-converter on the lens, making it even stronger. A typical lens in this range is a 70-200 f2.8 or f4, or a 75-300 f5.6.
The most utilized lens in our camera bag for nature photography is the 70-200mm f2.8 lens. It is the most versatile one for wildlife photography. It is compact, can be used with a 1.4x tele-converter without sacrificing any quality, and the f2.8 makes it a wonderful lens to use at night with a spotlight or flash. A medium telephoto lens together with an extension tube can even be used for macro photography.
How you can take a similar image
Lens: Medium telephoto lens.
Settings: Medium aperture to get every part of its face in focus. Medium ISO.
How: Shoot exactly with the direction of light to create minimal shadow on the face. Try and capture that highlight in the eye.