There is an issue with impedance differences. You should pick up Audio Technica’s CP8201 Microphone Impedance Matching Transformer. I got them here in Canada for $18, they should be cheaper in the US. I did find them a bit clumsy as one must use a 1/4″ to 1/8″ adapter, as well as bring 2 mono leads into the GL2 stereo input. To solve this I stole the transformers out of the CP8201 and made up a box with 2 XLRs on one side and 2 1/8″ female mono on the other. Works great, but with anything on the GL2 you have to keep it a distance from the tape mechanism or you get an interference drone. I place my box on the tripod or on my waist if mobile.
I also found out how to build a cheap Line Level to Microphone adapter at discovercircuits.com. You’ll need this if you want to connect your camera to the output of a mixer.