The term used in photography is a fast lens. It refers to lenses with apertures that open wide. The larger the aperture, the more light gets in.
All other things equal, the recording medium requires less time to achieve the same exposure with a wide aperture than with a narrow aperture. This is the reason for calling wide-aperture lenses fast.
Fast lenses can be advantageous over slower ones in certain shooting conditions and types of photography. They really come into their own where there is either low light (for example if you need to shoot indoors but can’t use a flash) or where you need to use a fast shutter speed (for example in sports or even wildlife photography). They are especially useful when you need both a fast shutter speed in low light (ie indoor sports).
Your sample sentence would then be worded this way:
- The shutter clicked noisily, its fast lens able to discern the shapes and structures of the ruin.
Note that to discern the images and structures requires more than the lens. It requires the image (facilitated by the recording medium as @Spencer notes) as well as the interpretation of that image.