To increase the depth of field, there are two typical methods below
(1) Increase depth of field.
(2) Narrow the optical path
This time we will explain about (1)
■Relationship between depth of field and operating distance
Below is a table of specifications for lenses from the same manufacturer, same series, and same magnification (X4).
W.D. The longer it is, the deeper the depth of field.
■Measure the actual depth of field thanks to the difference in operating distance
Tilt the 0.2mm pitch glass scale at 45° and observe it from above.
Comparative shooting with lenses from the same manufacturer and lens series with different operating distances.
(1) Observe with x6 optical magnification lens with operating distance of 40mm
If we judge that the focus is on a scale (0.2 mm), then the depth of field is 0.2 mm x (1/1.41) = 0.14 mm.
(2) Confirm with a lens with optical magnification X6 and operating distance of 110mm
If we judge that the focus is on two scales (0.4 mm), then the depth of field is 0.4 mm x (1/1.41) = 0.28 mm.
