In article <_JqdnV_6pv2l0iHZnZ2dnUVZ_oWdnZ2d@golden.net>,
Bill <bill@c.a> wrote:

have you checked any other previous responses suggesting similar things?

OK, I Googled "Nikon D50 Overexpose"  before I started this thread.  There
are many, many references to overexposure with this camera.  And as many
suggestions as to how to compensate for the overexposure.  And there was no
mention, that I found, of any problems with the lens.  Whatever terminology
we use here, outdoor shots are blown out, and not in "sharp" focus.  I had
taken over 10,000 shots with the Digital Rebel with no complaints with
exposure and sharpness.  I would have expected the same or similar results
with the NIkon.  So.....I will be visiting the camera shop today for some
further advice.  The owner is a professional photog, and not just a
salesperson.  Hopefully, I can get it right.

<Yawn> This really is starting to sound familiar.

I'm sorry.  I'm sorry.    I also drive a Ford, wishing it were a Toyota.  I,
as well as many in this group, am looking for suggestions, not criticism.

Thanks, I'll take that into consideration.

According to Thomas T. Veldhouse <veldy71@yahoo.com>:

    I agree that the lens is at least suspect.  Just because you
used a lens from the same manufacturer with the same range but with a
different body mount with no problems does not mean that the lens you
have on your D50 is good.

    Some sample images put on a web site (with full exif data) would
probably help us to analyze the problems.  On thing which I might
suspect is flare in the lens being mistaken for unsharpness.

    Of course -- at 300mm -- what shutter speed are you using?
Motion blur could easily come in at those focal lengths, especially
since it is effectively a 450mm lens when you take the crop factor into
consideration.

    The exposure problem, if it a consistent -0.7 EV could be a
problem with the lens not having accurate diaphragm stops compared to
its wide open condition (which is where the metering is done).

    If it is highly variable, one thing is that the D50 (and the
D70) require an auto lens to be used with the diaphragm ring set to the
smallest aperture (numerically largest) so the auto-diaphragm mechanism
can select from the full range of settings.  Relatively recent Nikon
lenses have a lock tab which will hold the aperture ring in this
position for use on auto-metering cameras.  (And the ones made for
digital only don't even offer an aperture ring, requiring all aperture
control to be from the camera body.

    How old is this Sigma lens?  I've read of problems with them (I
believe it was them) from their practice of reverse-engineering the
communications protocol between the lens and the camera body (though the
contacts), instead of paying the licensing fee to Nikon to get the full
spec.  So, with these, every so often a new camera uses more of the spec
than was used before, and Sigma lenses have to have their firmware
upgraded to get them to work well with the newer cameras.

    But -- if the exposure problem is dealt with by simply setting
the correction to EV -0.7, that should be fine -- just *set* it that
way.

    Do you check the histogram in the camera's display to help you
zero in on the proper exposure?  That is usually an excellent guide --
especially when augmented by the blinking of blown pixels from
highlights -- to let *you* decide which areas contain detail important
to  *you*, and adjust the exposure.

    Just for the fun of it -- do you have a hand-held exposure
meter?  Set it to the same ISO as your camera is using (200 by default,
unless you have turned on auto-ISO) and compare its readings to what the
camera selects.  Then see which gives the better image.  I suspect that
you will discover that sometimes the camera selects the better exposure,
and sometimes the handheld meter does.

    Just some thoughts,
        DoN.