a. Focal length (focus Distance lensa)
More and more long focal its-length (up 85mm), so size lens will automatic length. A small lens with focus distance to normal, that is between 28 mm until 50 mm.
The Lens with focus mention to easy be planed in order to small measure. To lens that very width (wide angle) lens size potency become bigger than lensa normal, because its design more complicated.
The Lens zoom also will make the lens more bigger. The element Lens zoom more many and more complicated until measure longer.
b.The Lens Open
This is factor very important, more and more big of opening lens, so will be big of measure.
c. Type Camera.
Camera rangefinder and mirrorless haven't design mirror in camera, until to easy for designer ti plan Lens that have measure smaller .
d. Lens generations..
The Lens age former (a film camera) or camera digital that srill 10 MP resolution, thats a small size, because while to be combinated with new camera,the quality very optimal.
Now, very much camera digital that image resolution is very good and to reach resolution is 36 MP.
If we set a lens old to new lens camera, quality will not optimal, So the picture not too detail and its possibility big in its photo seen there is deviatting color (chromatic abberation). <<grph>>