Originally posted by Wulifou I'll happily show my deep ignorance here : what's the point in defishing a fisheye ?? Isn't the fisheye effect the fun part of it ? Or did you mean that once "defished", the 10-17 is still much wider than the sigma 10-20 (which I did use on a Nikon D80 BTW, and I just loved it ...)?
thx a lot for clarifying, this topic is very interesting for myself as well
You can defish the fisheye image if:
- you don't own a rectilinear wide lens (but perhaps wished you had)
- you used a FE but later you wished that you had changed your lens to a rectilinear.
So, in a way you have two lenses in one. Note that you can go from fisheye to rectilinear, but obviously not the other way around. The resulting defished image might be less sharp than the equivalent from eg the sigma 10-20, especially in the corners, although the sigma is also known to be not that sharp at 10mm in the corners.
Note that a defished 10mm FE is the same as a rectilinear image from the Sigma at 10mm, not wider.
See
http://forums.dpreview.com/forums/read.asp?forum=1036&message=26331785
for example images from me.