Traditional white-light and fluorescent imaging techniques provide powerful methods to extract high-resolution information from two-dimensional (2-D) sections, but to retrieve information from a three-dimensional (3-D) volume they require relatively slow scanning methods that result in increased acquisition time. Using an ultra-high speed liquid lens, we circumvent this problem by simultaneously acquiring images from multiple focal planes. We demonstrate this method by imaging microparticles and cells flowing in 3-D microfluidic channels. (C) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.JBO.17.5.050505]