Mitutoyo M plan Apo 5x NA 0.14
I have used this objective since 2014. Two example photos below, first a Common brimstone, second a Cuckoo wasp. The reasons that I bought this objective is that it is an Apo and that it has a long working distance (WD) of 34mm. I bought the lens on ebay from a known seller but was still a little worried about the transport because this objective type is sensitive and must be handled with care.
Objective Mitutoyo M plan Apo
Magnification 5x
Numerical apperture (NA) 0.14
Resolution 2µm
Depth of Field (DOF) 28µm or 0.028mm
Working distance (WD) 34mm
Resolution r = λ / (2 * NA)
When the numerical apperture (NA) is 0.14 and the wavelength of light (λ) is asumed to be 0.550 µm (green light) the resolution (r) can be estimated to approximately 2µm;
r = 0.550µm / (2 * 0,14) ≈ 2µm
Depth of Field DOF = λ / NA^2
Depth of Field (DOF) is approximately 28µm or 0.028 mm;
DOF = 0.550µm / 0,14^2 ≈ 28µm or 0.028mm
Mitutoyo M plan Apo 5x example pictures
