What I mean by the Prime here is Fixed Focal Lens (FFL, lenses with fixed focal length. This lens retains the mechanical parts that can move to 'lock' object, but - in contrast with a zoom lens - the distance does not change its focus. With thus, to adjust the proportion of objects in the frame, the photographer must move closer or away from the object.
Examples of these types of lenses:
35 mm f/1.65
50 mm f/1.8
85 mm f/1.8
FFL lenses have fewer number of elements is not as complex & construction zoom lens, but has advantages, namely:Examples of these types of lenses:
35 mm f/1.65
50 mm f/1.8
85 mm f/1.8
sharp optical quality
fast response (due to fewer elements
The advantages of optical quality and speed of response led to the lens is suitable for a photo of a product or advertisement, as well as modeling.