The widefield microscopy is a simple technique which induces low photobleaching effect compared to confocal microscopy. It is adapted for long-time observation on thin sample or sample observed with a low magnification. You can observe colored samples thanks to color cameras, transparent sample thanks to phase contrast and interferential contrast and observe samples in fluorescence. It is less adapted for thick samples and morphology studies in 3D because of the blur due to the observation planes superposition on the image.
Images can be deconvoluted (mathematic processing) after acquisition in order to increase the resolution and the contrast.