One of the first problems we have to face when completing a
stack is finding out the number of shots needed. When in doubt
many will possibly try to do it by eye, which either will make
them take more shots than necessary or fall short. There are two
formulas that will allow us to find out the depth of field
(DOF)of every picture, once we know the depth of field ideally
we will let shots overlap around a 20%. The first of these
formulas is known as Lefkowitz formula 2 * CoC * f *(( m + 1)
/(m*m)) CoC refers to the circle of confusion; we will use
approximate values of 0.030 for full frame cameras, a CoC 0,020
for cameras with APS-C sensors and a CoC of 0.15 for 4/3
cameras, these calculations are based on CoC = d/1500 where d is
the diagonal of the sensor (43 mm in the case of full format
sensors). The use of zeiss formula is also extended d/1730, with
this formula the CoC for a full frame camera is 0.25 m refers to
the magnification (0, 5 X 1 X etc.) (f) refers to the aperture
we work at (f2.8, f4, etc..) Eg