Originally posted by Alliecat That's kinda cool.
Would you put the same kind of attachment on for a film SLR?
Is
this the kind of thing Mareket means by loads of lens adapters?
Well, I do not understand what you mean actually.
If you are talking about the Sigma lens (Sigma Fisheye Circular Image 8mm f4 Filtermatic), then you can reed a review on
Sigma Fisheye Circular Image 8mm f4 Filtermatic Lens Reviews - Sigma Lenses - Pentax Lens Review Database
Now that is a lens it is not an adapter, and as such it is used mounted on the camera as any other lens. It is a circular fisheye lens meaning that it project a hemisphere (everything in front of the camera with 180 degree coverage) on a circle on film plane. Since this is a full-frame lens, the diameter of the circle is made so that it fits on the film (film size is 36x24mm whereas pentax aps-c size is 23.6x15.7mm). From the photo above I can estimate that the diameter of the projected circle is little less then the width of the sensor or about 23mm.
Since I have also some film bodies (MZ-7) I have tested the lens on the film as well, and yes it gives a full circle with 180 degrees coverage. So I hope that i have answered your question if that was your question, otherwise, pleas ask again.