A method for producing an image of an object within a chamber of a microfluidic device includes providing the microfluidic device having x, y, and z dimensions and a chamber depth center point located along the z dimension. The chamber depth center point is located a known z dimension distance from a fiducial marking embedded within the microfluidic device. The method also includes placing the microfluidic device within an imaging system that includes an optical device capable of detecting the fiducial marking. The optical device defines an optical path axially aligned with the z dimension and has a focal plane perpendicular to the optical path. When the focal plane is moved along the optical path, the fiducial marking is maximally detected when the focal plane is at the z depth in comparison to when the focal plane is not substantially in-plane with the z depth.