Comparison of laser-scanning confocal microscope and a wide-field microscope performance in imaging a thick tissue (Swedlow et al. 2002). A 5-d-old quail embryo stained with Alexa 488 phalloidin (green) and DAPI (blue) was imaged by laser-scanning confocal (A–C) and wide-field microscopy (D). (A) A low-magnification survey image of the entire embryo. The head is at the top of the figure. The arrow points to the developing eye, the region shown at higher magnification in B–E. (B) x–z section (parallel to optical axis) showing position of the coverslip (arrow) and the location of the focal plane shown in C (dashed line). (C) A single optical section ∼50 µm below the exterior surface of the embryonic eye. Concentrations of actin at cell cortices are visible. (D) The same embryo imaged by wide-field microscopy and recorded with a CCD camera (Alexa 488 only). The image shown is one of the 60 recorded from a series of optical sections. (E) The same optical section as in D after restoration by deconvolution. No cellular details are visible in wide-field images of this thick tissue. Scale bars: (A) 1 mm; (C, also for B,D,E) 50 µm. (Images D and E courtesy of Jason Swedlow, University of Dundee.)