Your Lenovo laptop highly likely has a function key which in combination
with two of the F1-12 keys enables you to in/decrease screen brightness.
irrespective of the OS used.

Not entirely. Some models don't play well with Ubuntu. I have yet to find
drivers for the hotkeys on my ASUS K60. They have them for the eee series and
some others, but until I find some, I'm without my brightness, volume, contrast,
and wireless control hotkeys. It hasn't been for a lack of searching, either.
--

I have the same problem as timmytheimpaler on my newer toshiba laptop.
If using gnome, there is a "brightness" applet that can be added to
the panel (right-click on panel -> add to panel -> scroll down ->
select "Brightness Applet") which works fine for controling the
brightness.

A quick web search shows options from the command line similar to:
sudo echo -n 100 > /proc/acpi/video/VGA/LCD/brightness (change 0-100
(or 1-8) after echo -n) for brightness and
sudo xgamma -gamma 0.6 (change 0.6 from 0.0-1.0?) for contrast...

Though the above CLI lines can differ a bit depending on your model,
so if they don't work, may want to do a model specific search.
Also, if you have NVidia, I think I have read somewhere that there are
some driver updates you can install that have such options available.

I have to apologize, I do have a brightness shortcut in combination with the
'function' button.
I am astounded that Ubuntu does not have support for color, contrast and other
common monitor customization features. I am a photographer and need to be able
to have those controls. It surprises me that this seems to be overlooked or
maybe more accurately, is just not a priority?

Thanks to all that put there 2 cents worth in and to anyone that can solve this.

Colour calibration is a function of the graphics driver program and
that depends on the availability of drivers for Ubuntu. NVidia have
very good driver support and I'm able to customize RGB / Gamma /
Brightness / Contrast etc just as much as on a Windows system.

If the graphics on the system doesn't have a driver so uses the basic
default one then *basic* is what it is !!

Not sure if this is what you're after (not being into this sort of thing
myself), but after a little Googling I found lprof in Synaptic which,
according to its description "...is a color profiler that creates ICC
compliant profiles..." and is mentioned on a few websites talking about
monitor calibration.

You may also benefit from a manual for it.

www.retrevo.com/.../