Confocal microscopy is a type of fluorescence microscopy that uses a pinhole aperture to eliminate out-of-focus light from the sample, resulting in a higher resolution image with greater contrast. This allows for optical sectioning of the sample, where thin slices of the sample can be imaged at different depths to create a 3D reconstruction. Traditional fluorescence microscopy, on the other hand, captures all of the light emitted by the sample, resulting in a lower resolution image with less contrast. Confocal microscopy is commonly used in biological research, as it allows for the visualization of subcellular structures in 3D with high resolution.