How to Calculate Depth of Field

In order to calculate depth of field, a decision has to be made on what is acceptably sharp. For our calculations, let’s assume that features below 0.25mm are considered unnecessary when viewed in a 200x250mm print at 300mm distance.

Example: SubC 1Cam

Lens: Carl Zeiss Vario-Sonnar T*

Aperture: F1.8 ~ F3.4

Focal length: f= 3.8 ~ 38.0mm

Equivalent 35mm focal length: 26.0~260mm (16:9), 31.8-318mm (4:3)

Using this depth of field calculator, if we select the largest aperture of f1.8, use the widest focal length of 3.8mm, approximate a sensor size of 1 / 2.3” , and adjust the focus distance to 1m -- the calculator gives a depth of field of 2.79m.

Then if we apply a magnification of approximately 1.33x due to the flat port: Nearest Acceptable Sharpness = 0.44m Furthest Acceptable Sharpness = 2.5m Total Depth of Field = approx. 2m