When using common light microscopes, focusing is usually performed manually therefore it is time consuming and eye fatigue may be caused after a period of focusing especially through the microscope eyepieces. One solution to this problem is using an autofocusing system based on images of the observed object at consecutive focusing positions along the optical axis of the microscope. In order to design this autofocusing system, this study aims to evaluate well-known autofocus algorithms. A number of eight autofocus algorithms were evaluated with two sets of coconut fiber and algae images that had been captured using an available inverted light microscope with an 10x objective lens. Experimental results showed that the algorithm using autocorrelation as the focus measure function outperformed other algorithms and could be implemented in an autofocusing system.