These types of accessories are usually just fun to do a few tricks with, but nothing serious or of professional quality. That blurriness is probably normal, but there probably is something better that won't have the black edges. Never buy a lens without seeing sample images first, imo. Inexpensive third party lenses will have cheap glass inside. It's usually all about the glass with lenses (and motors if you have a dslr). I bought a set of macro lenses for my dslr last year and they were fun for a little while. I only paid $15, so they serve their purpose and I know I can throw one on my daily lense when I want to do something interesting. I say all this to explain the mindset one should have about these things.
So, have fun with what you got. Like any camera, you'll have the most fun in daylight conditions. Fish eyes are usually more interesting in outdoor settings, imo. Good luck.
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