The sports mode usually increases the shutter speed, lowers the aperture value (opens the lens up wider to let in more light) and sometimes also raises the ISO. When it does all this your camera is still supposed to give you the correct exposure, but for some reason it sounds like it's underexposing everything.
Obviously it's increased the shutter speed because the blur is decreasing, but I don't know about the aperture value.
Before you do anything I'd see if there is a new firmware revision for the camera that might fix this.
Something to test:
1) Take two identical (or nearly identical) pictures - one in "normal" mode and one in "sports" mode. It doesn't really matter what you take a picture of, but outside in the sun will work best (a cactus maybe). Have someone check and see if the flash is firing (it shouldn't).
2) Transfer them onto your computer and open them with some sort of software that reads and displays EXIF info. If you don't have any software that shows you EXIF info download Irfanview <A HREF="http://www.irfanview.com/" target="_new">http://www.irfanview.com/</A> (it's free). Don't forget the plugin pack as well.
3) Have a look at the EXIF info (in Irfanview hit "I" and then "E" after loading the image).
It should look something like this:
Make - Canon
Model - Canon EOS 10D
Orientation - Top left
XResolution - 180
YResolution - 180
ResolutionUnit - Inch
DateTime - 2003:08:31 15:46:35
YCbCrPositioning - Centered
ExifOffset - 196
ExposureTime - 1/125 seconds
FNumber - 16.00
ISOSpeedRatings - 200
ExifVersion - 220
DateTimeOriginal - 2003:08:31 15:46:35
DateTimeDigitized - 2003:08:31 15:46:35
ComponentsConfiguration - YCbCr
CompressedBitsPerPixel - 3 (bits/pixel)
ShutterSpeedValue - 1/125 seconds
ApertureValue - F 16.00
ExposureBiasValue - 0.00
MaxApertureValue - F 5.60
MeteringMode - Multi-segment
Flash - Not fired
FocalLength - 67 mm
etc, etc...
The important things we're going to look at are ShutterSpeedValue, ApertureValue, and ExposureBiasValue.
4) Make sure ExposureBiasValue is 0 (your camera may or may not support this). If it's anything other then 0 you've probably accidentaly toggeled a setting somewhere in the camera. A negative number will make it darker, a positive number will make it lighter. If all else fails you could try telling the camera to overexpose the picture in order to brighten it up.
5) Look at the shutter speeds and aperture values. Check the "normal" picture first and write down the values (ie: 1/125th and F16.00 in my example). Now compare them to the "sports" values. The shutter speed will be faster (because you said you have less blur) so it might be something like 1/1000th (sports) vs 1/250th (normal). This is a 4x increase in shutter speed, so we need to make sure the camera is opening the aperture 4x as wide as well. In my example I started off at 1/125th and F16.00, so if my shutter speed increased to 1/1000th my aperture should become F5.60. This is all assming the ISO value (ISOSpeedRatings) remains constant (200 in my case).
Your lens is probably very different (I have a dSLR) and you should probably see something more along the lines of 1/125th & F8.00 vs 1/1000th & F2.80.
See what you get. Can't really suggest anything else unless you try the test and post the ShutterSpeedValue, ISOSpeedRatings, ApertureValue, and ExposureBiasValue from both pictures (or email me the two pictures).
BTW: If you're not sure how shutter speeds, apertures, and ISO levels tie together read this thread: <A HREF="http://forumz.tomshardware.com/ce/modules.php?name=Forums&file=viewtopic&p=2360#2360" target="_new">http://forumz.tomshardware.com/ce/modules.php?name=Forums&file=viewtopic&p=2360#2360</A>
*Dual PIII-800 @900 i440BX and Tualeron 1.2 @1.7 i815*<P ID="edit"><FONT SIZE=-1><EM>Edited by JCLW on 05/26/04 03:17 PM.</EM></FONT></P>