Lens Diameter - Is bigger better?

LINVS · Nov 29, 2016

I'm very new to photography and am exploring film.

I ordered a Contax T3 based on all the excellent reviews. Now since the lens is much smaller than a SLR lens (I have been shooting with a Nikon F), will the Contax Len perform worse than my Nikkor lenses?

compur · Nov 29, 2016

Image quality of a lens isn't determined by its size.

You may be thinking of the lens' ability to function in low light which is determined by the ratio of focal length divided by aperture diameter. This is referred to as the speed of the lens but, again, it's not the image quality of the lens.

Your T3 should provide very good image quality as long as you do your part.

KmH · Nov 29, 2016

Lens diameter tends to increase as a function of the fastest (widest) lens aperture the lens is capable of.
The longer the focal length of the lens the wider the diameter of the front lens element.
Fast lenses tend to have better optics than slower lenses.

Also, the wider the front lens element is relative to the lens focal length, the more the lens costs.
Nikon's AF-S 50 mm f/1.8G prime lens sells new for $220.
Nikon's AF-S 200 mm f/2G prime lens costs $5700.

So if you want a fast lens - a wider lens front element diameter will be included.

Derrel · Nov 29, 2016

This is a flatbed scan of a 45mm P-Nikkor, an /2.8 "pancake" type lens scarcely one inch tall from front to mount. Also shown is a 52mm filter-diameter lens cap, and the special "bowl" lens shade.

A very good article on the Contax T3 can be found here:

The Contax T3 - A regular companion - 35mmc

A pretty fair number of lenses over the years have had VERY small front objectives, and yet, offered VERY sharp images! The Nikon 55mm f/3.5 Micro~NIKKOR and the 60mm AF-D Micro~NIKKOR designs had dime-sized front elements, as did the 45mm f/2.8 P Nikkor; all three of these lenses had the dime-sized front element, and yet, offered extremely good optics.