  We test the effects of reconstruction techniques on 2D data to determine the
best approach. We obtained a time-series of spectropolarimetric data in the Fe
I line at 630.25 nm with the Goettingen Fabry-Perot Interferometer (FPI) that
are accompanied by imaging data at 431.3 nm and Ca II H. We apply both speckle
and (MO)MFBD techniques. We compare the spatial resolution and investigate the
impact of the reconstruction on spectral characteristics. The speckle
reconstruction and MFBD perform similar for our imaging data with nearly
identical intensity contrasts. MFBD provides a better and more homogeneous
resolution at the shortest wavelength. The MOMFBD and speckle deconvolution of
the intensity spectra lead to similar results, but our choice of settings for
the MOMFBD yields an intensity contrast smaller by about 2% at a comparable
spatial resolution. None of the reconstruction techniques introduces artifacts
in the intensity spectra. The speckle deconvolution (MOMFBD) has a rms noise in
V/I of 0.32% (0.20%). The deconvolved spectra thus require a high significance
threshold of about 1.0%. A comparison to spectra with a significantly higher
S/N ratio and to spectra from a MHD simulation reveals that the Goettingen FPI
can only detect about 30% of the polarization signal in quiet Sun. The
distribution of NCP values for the speckle-deconvolved data matches that of
observations with higher S/N better than MOMFBD, but shows seemingly
artificially sharp boundaries and unexpected changes of the sign. For the
spectropolarimetric data, the higher intensity contrast of the speckle
deconvolution is balanced by the smaller amplification of the noise level in
the MOMFBD at a comparable spatial resolution. The noise level prevents the
detection of weak and diffuse magnetic fields.
