Originally posted by elliott
The Russian made Zenitar 16mm f2.8 fisheye isn't very much of a fisheye on APS-C and it is pretty good at f4 and beyond, it is by far the cheapest option.
I have one that I used a lot before I got the DA15. With mine you really have to stop down to f/8 (f/4 is unusable), at which point it's very good indeed in the centre, and OK at the edges. Post-DA15 acquisition, though, it doesn't get a lot of use. I defish in PS with a plug in called Debarrelizer.
Mine was another one that needed adjustment to the focusing ring to make it focus to infinity.
I think it's worth the money, but it was one of those purchases where I might just have well waited longer, saved a bit of money, and bought the more expensive lens in the first place. I have a number of cheap (but good) lenses which fall into that 'false economy in the long term' category.