Systems and methods for laser capture microdissection are disclosed. One method incorporates the step of changing the beam diameter of the laser to adjust the size of the activated area of the transfer film and as a result, the size of the at least one microdissected portion of the sample adhered to the transfer film. Changing the beam diameter while operating the laser in idle mode permits the user to visualize the spot on the desired portion of the tissue sample and simultaneously increase or decrease the beam spot to optimally match the beam spot size with the portion of the tissue to be extracted. This method advantageously provides increased accuracy in microdissection and reduced heating of the tissue sample.