My mom turned me onto this trick: take the eyepiece off an old camcorder and stick it on your digital camera. Voila, instant microscope!  Between the magnification of the camera’s zoom, the eyepiece, and zooming in on the image, you can display the eyes of the spider on the viewfinder at at least 10x magnification.  And the whole thing still fits in your pocket!

Of course, a more sophisticated solution can produce pretty amazing results!