In article <01bc1de7$b73b9f00$9bd05fcf@ksbdev1>, sbrooks@waymark.net says...

>I want to buy a wide angle lens for my N70. Listed in a mail order
>catalogue I see the following:
>14mm f3.5 W/Hood
>15mm f2.8 Fish Eye W/Hood
>1) What is the difference, in degrees of coverage, between the 14mm and
>15mm?
>2) What does the f3.5/f2.8 notation mean and how do the two values compare?
>3) What's a fish eye?

Hmmm, if you are just beginning, I would suggest starting with more
moderate lenses, unless you have a real need/desire for an extreme
wide-angle - even most experienced folks have little idea how to use
them (though I must admit to a certain addiction - I have about five
super-wides...). A 24mm, or the really excellent 20mm f2.8 Nikkor,
gets you a very wide lens, high image qiality, and somewhat greater
ease of use than a 14/5/6mm lens... The Sigma 14mm is a "rectangular
perspective" lens (straight subject lines are rendered [nearly]
straight by the lens), with about 115 degree coverage (measured on
the frame *diagonal*) - The fisheye is a "spherical perspective"
lens (straight subject lines not running through the center of the
image are rendered curved [more curved, the further from center] -
examples of this type of perspective can be seen in the reflections
in a spherical Christmas tree ornament, or in a curved store security
mirror), with about 180 degrees coverage (measured on the frame
*diagonal*). "F3.5, f2.8, f1.4", etc. refer to the maximum relative
aperture of the lens (smaller number [f1.4] is "faster"), and indicate
the "speed" (light gathering ability) of a lens - though with super-wides,
lens speed is not very relevant (they generally must be used at small
stops for good performance, and since the image magnification is much
lower with these lenses, very slow shutter speeds can be used hand-held
with them [1/2 second is practical, and 1 second possible with an 8mm fisheye...!]).
Hope This Helps