I'm to get a magnifying glass to move over a map to magnify a portion of it. I watched a tutorial that said to use and adjustment layer and the Magnify and Bulge effects. However, when I try this out myself, the underlying image isn't crisp, even though it's a vector .eps file. The file is nested in a comp, but when I try it on the map directly the blurriness remains. I have Continuously Rasterize selected.
I'm not sure what you expect. Effects are pixel-based and pixels get smooshed up with resampling. The behavior is perfectly normal. Whatever tutorial you are referring to is probably not the best in the world. That said, if you want sharpness and have a vector file, then simply duplicate and scale it and mask out the regions you want to serve as the magnified region e.g. with a circular matte.