Fly on the outside window. No, the window glass is dirty thus the artifacts. This made use of the 85mm f/1.8 lens with the extension tubes and 2x teleconverter for a touch more standoff than using it with the 50mm f/1.8 II lens (in lieu of the MP-E lens I do not have).

Shot was made from a tripod and using a remote trigger to avoid more movement in the shot