Some photographers like to have a huge range of lenses covering every focal length imaginable from extreme wide angle to long telephoto. In practice though, this is more often a sign of gadget mania rather than real necessity and most will find that working with just a few excellent quality lenses is a far better strategy.
When photographing a nude model, most photographers will aim to produce an image that is aesthetically pleasing without distortion or unflattering effects. With a distant scene such as a nude figure in the landscape it is perfectly possible to use a wide angle lens, but as you move closer that same lens is likely to cause unwanted distortion and this is particularly prevalent with cheaper lenses. When working in the studio using a full frame 35mm camera, I tend to shoot with lenses no wider than 35mm at most and even that is not ideal most of the time.
Perhaps surprisingly to some, one of the best lenses available for photographing a nude body is the often discarded standard 50mm lens, which is generally the cheapest option in every camera maker’s lens range, but invariably of excellent optical quality, suffering from almost zero distortion or chromatic aberrations.
When photographed in relative proximity the female nude will often appear slightly more curvaceous than in reality with a 50mm lens but not in an ugly or exaggerated fashion and the same rule would apply equally to glamour photography. This is roughly equivalent to the 80mm lens on the medium format Hasselblad, which is my first choice when photographing nudes, since I tend to prefer to the less elongated proportions of medium format.
Another alternative lens would be the 85mm, though often considered more as a portrait lens all the main camera makers such as Canon and Nikon etc. produce an optically excellent version and this can be used in just about any situation to good effect. Much like the 50mm lens it also generally has a fast maximum aperture allowing the photographer to easily blur the background if desired.
One alternative option that should not be overlooked is a good quality zoom lens, such as the Canon 24-105L for example, which covers all the necessary focal lengths for most requirements while removing the necessity to change lens every 30 seconds during a shoot. There was a time when zoom lenses were not really an option for high quality professional usage but nowadays the better lenses are very good indeed and extremely convenient.