The D-100 has a 23.7 × 15.6 mm CCD with 6.31 million total pixels and 6.1 million effective pixels (giving 3008 × 2000 pixel images). These calculations estimate the total pixel dimensions, effective sensor size, and focal length multiplier.

Total Pixel Dimensions

Here we estimate the horizontal (H) and vertical (V) pixel dimensions for the sensor.

Assume we have square pixels. Then H = 23.7 / 15.6 × V.

Given that the product of H and V is 6.31 million, we can substitute and solve to find that:

The sensor has about 3096 horizontal pixels and 2038 vertical pixels.

Effective Sensor Size

We can scale the total sensor width and height by the ratio of effective to total pixel dimensions to estimate the effective sensor width and height:

The effective sensor size is about 23.0 mm × 15.3 mm.

Focal Length Multiplier

Since the effective sensor size (and image size) has an aspect that is a bit wider than 3:2, we divide the vertical dimension of 35 mm film (24.0 mm) by the effective height of the sensor (15.3 mm) to find that:

The focal length multiplier is about 1.57.