Originally posted by Sten Got the lens Sigma 70mm F2.8 EX DG macro today.
Shot a few pictures without any arrangement at all.
The first picture was at a fair distance so it got decent depth-of-field (DOF), but of course if I had wanted a good picture, then I would have removed the blurry flowers in the background.
The second picture was close, so its DOF was extremely shallow - focus was on the yellow dark-spotted area slightly to the left and below the middle. This is the kind of picture that I will try when I get my new equipment from Cognisys (Stack Shot) next week. Then I will take a lot of pictures with different focus with Stack Shot and then hopefully combine them into one single all-sharp picture with the software Zerene.
Best regards,
Sten
Sten,
The dof for your system is
d = 2CN((1+m/p)/m^2 ~ .04N(1/m+1/p)/ m where N is the f-number on the lens. P is the Pupilary ratio (exit pupil over entrance pupil diameters).
The pupil is how big the aperture looks from outside the lens. To estimate it, just open the lens fully, hold the lens at arm's length, and use a ruler to measure the aperture diameter - do that for both entrance and exit sides of the lens. Report back & we can make up a table to guide you in how big a step size to use for stacks.
This is not really necessary of course, but it is fun for me.
Dave