What's the best fish eye lens money can buy for canon full frame body?

Question

I'm looking for a fish eye lens to use with my 5d.

The alternatives I can see are canon 8-15L f/4 and canon 15 f/2.8.

Canon 15mm is a prime and it has a faster aperture, while 8-15 is an L lens.

The way I understand the matter, there's little advantage to having fish eye zoom on a full frame body (besides making semi circular pictures all the way down to 8), and the zoom was invented to help the users of cropped sensors.

Did anyone compare the two side by side? Which one gives sharper/better picture quality? Is there anything else that I should mind about fish eye lenses?

Answer 1

The zoom helps with crop sensors but that's not the main reason. Basically on a full frame sensor the 8-15 is two lenses in one, at 8mm it's a full fisheye with a circular image and a 180 degree vertical field of view. At 15mm it's a diagonal  fisheye, with 180 degrees corner to corner and no black areas.

Even if you don't want to shoot circular images I would still recommend the L as its reportedly sharper in the corners. The slower maximum aperture really isn't a concern with a fisheye lens as the depth of field is huge at those focal lengths, and camera shake virtually non-existent!