The Vivitar 7mm F/3.5 fisheye manually operated lens is fun to use, and easy to use. It has a good build quality, very good performance stopped down, and most importantly, it’s affordable! Just remember when shooting with this type of lens; good results are predicated on exploiting the fisheye “look,” or perspective, with lighting considerations being secondary. Don’t worry about sharpness, color fringing, and all the other stuff that has little to do with making a good picture. If you’re outdoors, stop it down to F/11 and set focusing to infinity and shoot! To meter correctly, just check your LCD and use exposure compensation as necessary. Believe me, it’s an easy lens to use, don’t be intimidated by the all manual operation.
Optically, this fisheye lens is quite good, and I’d highly recommend it for people that have APS-C cameras. It’s sharp stopped down, and control of color fringing, light fall-off and ghosting is above average.
Cost conscience people will want to look closely at this lens, as it’s one of the few inexpensive fisheye lenses made for exclusive use on APS-C cameras today.
Although Sony’s 16mm F/2.8 fish-eye (review) seems a little sharper in the centers, it’s also much more expensive, and not appropriate for use on an APS-C camera, as the distortive effects are diminished by the crop factor, that’s why it doesn’t make any sense to directly compare them.
Also note; The Vivitar 7mm F/3.5 fisheye is being marketed under various brand names including; Bower, (which uses “8mm” instead of 7mm, but that’s just marketing BS to make you think it’s different) and probably Samyang, Walimex, Opteka, Rokinon and Falcon.