  We propose an holographic microscopy reconstruction method, which propagates
the hologram, in the object half space, in the vicinity of the object. The
calibration yields reconstructions with an undistorted reconstruction grid i.e.
with orthogonal $x$, $y$ and $z$ axis and constant pixels pitch. The method is
validated with an USAF target imaged by a $\times$60 microscope objective,
whose holograms are recorded and reconstructed for different USAF locations
along the longitudinal axis: -75 to +75 $\mu$m. Since the reconstruction
numerical phase mask, the reference phase curvature and MO form an afocal
device, the reconstruction can be interpreted as occurring equivalently in the
object or in image half space.
