How do you intend on using the Loupe for a digital file, or a computer
-inkjet print. A loupe will be pretty worthless. A poor quality
lens however will show things like color fringing or other (aberrations)
and those kind of things possibly won't be noticeable to an average user
as opposed to professionals or important clients. Then again the glass
maybe fine but there may be trade offs like small maximum aperture, or
even fixed aperture.

To put this into perspective when I got my D70 last June I put a set of
closeup filters on the lens to make detail shots of some flowers, Yes in
some places the camera picked up color fringing from the use of the
filters. I would more than likely put the GAF lens you inquire about on
par with the filter set- FWIW.

<snip>

The main difference is the focal length.  Will you see a difference?  At
least in terms of field-of-view the answer is yes.  Is it worth buying
another lens with 90% duplicated coverage?  Maybe not.  You might want to
pick up a fast ultra-wide prime for the same money.

    Not having used the 28-80mm lens which you have, I can't really
answer your question.

    However -- I have another question of my own:

    How did the "bundle" price compare to that of the D70 "body
only" and the D70 "kit" (that is, with the 18-70mm lens?

    And what other things might have been tossed in to the "bundle"
to make it perhaps a better deal than it seems.

    The normal D70 in "body only" format comes with:

1)    The body (of course).

2)    A body cap, to keep dust out of the camera's interior
    when no lens is mounted.

3)    One battery.

4)    The battery charger and power cord.

5)    The neck strap.

6)    A clip to blank off the eyepiece when shooting with no eye
    at the viewfinder.

7)    The owner's manual.

8)    Whatever packaging.

    Note that there is *no* Compact Flash card with the "body only"
package.  You are expected to either have some CF cards, or to purchase
your own choice at the time you purchase the camera.  (While I had some
CF cards already, they were far too small for reasonable use in a D70,
so I purchased a Lexar 1GB 80X card at the same time.  I also purchased
a spare battery, so I could be sure to be able to swap out a nearly
discharged battery in the middle of a lot of shooting.  I subsequently
bought a second identical CF card.

    There is also no camera bag, and no tripod.  I have seen both
made parts of bundles which I opted not to try, because I already had
(several of) each.  I saw these when checking out eBay offerings, before
deciding that a local dealer would be the better choice for me.

    So -- did you get the $300.00 difference in other equipment
which *you* could use?  If not, you may have been seriously ripped off.

    I can't compare what you paid with what I paid, because I
suspect that you purchased yours quite a while after I got mine.  This
is, in part, because you refer to it as an "$800.00 camera body", and
mine cost me $999.00 from a local camera dealer (part of a chain).

    At that time, the "kit" was significantly over $1300.00, and I
thought that I did not need the "kit" lens.  I subsequently decided
otherwise and purchased one.  The lens which you received is less (in
terms of focal length range) than the lens which I already had, and
which has been excellent aside from lacking sufficient wide angle
capability.

    Good Luck,
        DoN.

Main difference for most people is mostly going to be in the field of view,
wider lenses are more expencive to make. Plus the better lens most likely
is better at larger fstops, while the cheaper lenses normally are only
really good at 1 or 2 fstop settings near the middle of their range.