I'm not familiar with that particular camera, but indoor sports shooting
(especially when not lit by professional lighting) does tend to "push the
envelope" of even the best equipment.

It brings out a whole bunch of contradictions that require a few
compromises:

* Ideally you need a fairly high shutter speed (usually 1/640th or above) to
totally freeze the action - but that means (in the low light) that you need
an exceptionally wide-aperture lens. If you don't have an exceptionally
wide-aperture lens then then you might have to shoot slower (and risk
movement) - or up the ISO (often to the point of very grainy images).

* The relatively subdued lighting makes it hard for the auto-focus to work -
focusing can be slower and less accurate - once again a wide-aperture lens
helps with the focusing, but also reduces your depth of field (although it
becomes less of an issue the further the subject is away from you).

* And of course if you're forced into using a low shutter speed then camera
shake also comes into the equasion.

Often, it requires a combination of things that current technology just
can't deliver (assuming we're after a Utopian "perfect result").

From a practical point of view, some things to try ...

* Max out the ISO
* Open up the lens to the max
* Use a good flash if possible (the high ISO extends it's range)
* Consider under-exposing by a stop ("or so") and adjusting with photoshop
afterwards (so you can use a higher shutter speed)
* If you can use a tripod with a gimbal head (like a Wimberley head) then so
much the better.

At the end of the day it comes down "you get what you pay for" - an F1.2
lens will do a better job than an F4.5 - a Canon 1DsMk2 will do a better job
of focussing in poor light than one that costs a lot less etc etc etc. Damn
it :(

are you shooting in "RAW" format?
ae you shooting in auto mode?
I've been having a blast using my Sony A-100 and have been adjusting
from a 35mm mindset to digital. I've been getting great (well good)
results, but found I can better "tweak" my shots when capturing in RAW
format and using the software from Sony.

-Art- (not Art)

Is the poor focus due to poor AF or is it really just slow shutter
speeds blurring the subject.  The Maxxum 7D has pretty fast AF and I
assume the A100 inherited that as well.  (At least its fast with the
high end lenses, not sure about the 75-300).

For your child shots the best thing is to add a flash and simply point
almost straight up at a white ceiling.  The light will look very natural
and your success rate will shoot way up.

If you're shooting at 300mm (f/5.6), then the AF will be compromised by
less light getting in and this may contribute to focus error.

The Minolta 75-300 is not a great lens by any stretch, although pretty
good (sharp) from 75-200mm.  200-300 it is a little softer, and of
course increasingly slow with focal length. (f/5.6 at 300mm).  I had one
and it's best use for me was actually for portraits (on film) in the 75-
125mm range).

I shoot sports with Minolta 28-70 f/2.8 and 80-200 f/2.8 constant
aperture lenses and even then it is a challenge in available "school"
lights.  While both of these lenses are very sharp, esp. the 80-200,
nothing beats having more than enough light.  I shoot indoor available
light with 200 film (such as Ektachrome 200) EI'd at 640 and pushed 2
stops in development.  (A poster in rpe35mm suggested that film/exp/push
regime and it works very well.  Thanks Gordon.)  For digital I shoot ISO
200 - 400 (Maxxum 7D).

For volleyball I bring two studio strobes and fire them remotely.  This
is a mixed blessing as I set the exposure for the net, so action closer
to the strobes is over lit and beyond the net well under lit as dictated
by 1/r^2.  I often shoot at low shutter speeds (1/10 - 1/20) in rear
sync to get "trails" on the balls.  (Monopod).  I like this effect
although it blurs legs and arms a bit and many object to it... this
lighting also creates harsh shaddows on the floor making saves look very
spooky.  At slow shutter speeds a lot of the sodium vapour light breaks
through casting an erie green/yellow.

So, shoot faster ISO's (800) where the A100 is unfortunately a bit
noisy, but tolerably so for smaller prints and get that lens as open as
possible.  If you can, get faster lenses.  The 75-300 at f/5.6 at the
long end is not an indoor sports lens by any stretch.

Cheers,
Alan.