The size or weight or a lens influences how practical it is to handhold. Prime (fixed focal length) lenses are generally smaller and lighter than zooms as they contain fewer elements. The maximum aperture of that lens is also important because it determines the fastest shutter speed you can use in any situation. One of the best lenses you can get for handholding is the 50mm prime ‘standard’ lens as it’s small and light and has a very ‘fast’ maximum aperture. The Canon 50mm f/1.4 only weighs 290g, for example, whereas the Canon 24-70mm f/2.8 weighs 805g. The 50mm f/1.4 is also two full stops faster than the 24-70mm f/2.8, so in a situation where you were taking pin-sharp handheld shots with the 50mm wide open at f/1.4 and 1/60sec, you’d be struggling with the 24-70mm wide open at f/2.8 because the fastest shutter speed you could manage in the same conditions would be 1/15sec, for a lens weighing almost three times as much!