As seldom as a fisheye is called for, I didn't have the $ to justify a brand name lens.It is a manual focus, manual aperture lens, so you have to fiddle with the exposure before shooting critically.The lens does not project a circular image on the sensor. It fills up the frame with image which is usably sharp to the edges. (Doesn't project a circle on a non-C camera, either).Focus is a matter of guessing the distance to the subject and setting it on the lens barrel. With such a deep depth of field, if you stop down to f8, almost everything is in focus anyway.Heavy, solid feel lens. Acceptable results. Because of the comparitvly low cost, I am a bit more daring with this lens - get right up in someones face, where distortion is unique.Since the projected beam from a single flash doesn't come close to covering what the lens sees, multiple flashes, bounced, preferred to approximate even lighting. Just a warning.If someone else is buying, get the Name brand lens. If you're buying and only shoot occasionally with this lens, it is a bargain. And you should only shoot occasionally with a fisheye anyway.