Zoom lens
In general, such lenses have a lower aperture than comparable fixfocus lenses. Depending on the manufacturer common zoom lenses (in the 30–100mm focal range, for film photography) usually have a varying aperture, from 4 to 5.6, perhaps 3.3 to 5.6. There are also some zoom lenses with a fixed maximal aperture (to take the example from before: of 2.6 or 2.8, maximum). In contrast, fix-focus lenses in that range have maximum apertures of 1.4 to 2.