1) The FC-E8 fisheye converter (x 0.21) was intended to be used onto the zoom-lens of the older Nikon 9xx Coolpix family. It has been since replaced by the FC-E9 model that seemingly did not match the optical properties of the forerunner in spite of its much larger dimension and weight.
It shall be compared with
2) The Sigma AF 8mm f/4 that is very popular amongst panographers. Associated with APS-c type DSLR, it is the favorite fisheye of most Canon DSLR users as there is no "short" focal length fisheye lens currently available for them. On the contrary, Nikon makes and sells currently the recent Nikkor 10.5 mm f/2.8.
Update in Fev 2006: this has changed as many Canon (fulframe camera) Users have adapted the (shaved) Nikkor 10.5mm on EOS 5D or EOS 1DS. Furthermore the Sigma 8mm is ideally suited for the Nikon DSLR cameras as it allows to shoot a fewer number of photographs to produce full 360° panoramas (the older and better Nikkor 8mm has unfortunatelly been discontinued a long while ago).
The Nikon FC-E8 converter has been simply adapted in front of the EFS 18-55mm f3.5-5.6. That lens is still provided with some of the Canon DSLR as a "kit" lens.
Clik here to enlarge (JPG 204ko)
From some trials results, it seems that the best aperture is f/11. The zoom-lens was here set at 35mm in order to best simulate the angle of view of the Sigma-EOS 300D combo. About one EV unit value is lost in the process.
Click here to enlarge (Beware: JPG 3,3 Mo!)
Crops of some of the above image
To enlarge (JPG 180ko)
Near the edge of the picture:
To enlarge (JPG 200ko)
f/8 is one of the best setting for that lens.
(Beware: JPG 4,3Mo!)
To enlarge (JPG 100ko)
Near the edge of the circular image:
To enlarge (JPG 500ko)
As could be expected the Sigma is much sharper. It also is better when color aberration is concerned.
The FC-E8 converter cannot match the Sigma for its optical qualities.
EF-S 18-55mm + FC-E8 combo on a Canon EOS 20D
1.6 sec; f/16; ISO 100; f=30 mm 18-01-2005
Sigma 8 mm f/4 on a Canon EOS 20D
1,6 sec; f/16; ISO 100; f=8 mm 18-01-2005
Rev: january 2007 (comparison of output panoramas)