I love fisheye images, and this lens gives me the option at a very fair price
[Dynax 7D, Sigma 15mm f2.8 fisheye]
Fisheye lenses can give some fantastic pictures and I have always wanted to own one. It's not a lens that you use every day, but once in a while you can obtain some really good results with a fisheye.
The Sigma 15mm is a very accessible lens. Its prices makes it a very fair option if you want to play with the effect. On a film camera it's amazing, while the effect is not quite as astounding on an APS-size sensor.
The Sigma is a socalled diagonal fisheye (as opposed to circular) and covers the whole image plane, even on film. It has an image angle of 180 degrees diagonally, which gets a lot into the image. You often get your own toes in the image if you aren't careful.
Super quality
This is a lens that is very hard to beat at the price. It's super sharp, has a very handy size and weight and still a physical quality, which is top notch.
I have often used it as a super wideangle lens and used a Photoshop plugin to correct the curving lines that it produces. As much as I love the fisheye look, the effect can also be too much if used over and over again. But the amazing perspective you can obtain with a 180 degrees diagonal picture angle, can be quite surprising. On an APS sensor size camera the effect is not quite as stunning, but it still works.
