Differences between fisheye lenses? Pics?

Canon Fisheye EF 15mm f/2.8 Autofocus
Sigma Fisheye 15mm f/2.8 EX DG Diagonal
Sigma Fisheye 8mm f/3.5 EX DG Circular

Does anyone have any pictures to represent the differences between these? I want to get a fisheye, but Im not quite sure what I want. (aside frm the obvious fisheye lens effect)

Any pics or good explanations of difference? Thanks!

The Canon EF 15mm f/2.8 Fisheye takes sharper photographs on my Canon EOS 5D than the Sigma 8mm f/4 EX DG Fisheye does on my Canon EOS 20D, but then again every lens takes sharper photographs on my 5D than on my 20D.

I've never tried the Canon EF 15mm f/2.8 Fisheye lens on my 20D and only once have I tried the Sigma 8mm f/4 EX DG Fisheye on my 5D...something I will never do again. Each of these lenses have their advantages depending on the type of camera you have.

The Sigma 8mm f/3.5 EX DG is new and I'm not sure if anyone has had a chance to use it, but as I understand it, it will no longer have darkness on the outside edges of the image like the Sigma 8mm f/4 EX DG Fisheye does (which never really bothered me in the first place). Also, when I bought my Canon EF 15mm f/2.8 Fisheye lens I investigated the Sigma 15mm f/2.8 EX DG Fisheye lens and reviews seemed to be about dead even. In the end I eventually selected the Canon EF 15mm f/2.8 Fisheye only because of brand loyalty.

That said, if you have a camera with a 1.6 crop factor, I wouldn't buy a 15mm fisheye lens at all; regardless of the brand.

I second the 15mm on the 1.6 crop bodies, you dont really get much of a fish-eye effect. Have you seen the peleng 8mm fisheye? Here's a review: http://www.photozone.d​e …ses/peleng_8_35​/index.htm and some sample pics.

I got this on ebay, quite cheap and works great although tricky to start with (see the review above for details on how to work it).

I have a 5D, so no worry about that.

I've been reading more threads but havent found any direct comparison shots on a subject. I think I am leaning towards a Sigma or Canon 15mm. I might grab the Sigma just for the focus ring. I'm not fond of the focus ring on my 1.8 50, and the 15 seems to have that same function.

Try this one. 8 and 15 0n FF and crop, thanks to HKFEVER.

Perfect!!! Exactly what I was hoping to find!

I'm sold on the 15! I use a 5D, and that 8mm looks like a peephole! May be great for some stuff...but not for the vision in my mind!

Now to decide on Canon or Sigma...

8mm will be a perfect circle on FF, not really what you want