Pixels and Perception

Sharpness has become a mainstream aesthetic. It's not unusual to hear rhetorics such as "it's between a sharp image and a missed opportunity."

But what do we really mean by sharp?

There is sharpness at the focal point, which requires understanding of the mechanisms of photography. Think the exposure triangle (or tricycle, as some refer to it)[1].

There is sharpness by display. Think retina display.

Then there is sharpness by perception.

Below is an investigation on the last, focused on digital production and dissemination.

I am writing it out simply because I sense a data inflation among all the screens that surround us, and I'd like to do some calculations to prove my hypothesis.

Image as Data

In the broadest strokes and from my current understanding, three things affect digital sharpness:

the photosensor determines the capacity of maximum data input
the image quality (a setting on the camera) regulates the actual data stored
the display/physical medium that outputs the image (to be perceived by a human)

A digital Input to a digital Output interests me the most because of its potential to show how the sharpness we think we are seeing might be something quite simple. We might be able to rethink about sharpness and the tools we use to produce it.

Photosensor

This actual size of the 5D Mark III sensor is 36mm x 24 mm.

surface area	864 mm²
photosites (pixels)	22,300,000
pixel pitch	6.22 µm
photosite (pixel) area = pixel pitch²	38.69 µm²
pixel density[2]	2.58 MP/cm²

Pixel pitch tells you the distance from the center of one photosite(pixel) to the center of the next. The larger the photosite, the more light it can capture and the more information can be recorded. Pixel density tells you how many million pixels fit or would fit in one square cm of the sensor.[3]

Image Quality

something

Display