I am having difficulties getting good indoor sports photography action shots using my D70s (ISO pushed to 1600), Nikon 80-200mm F/2.8D lens and aperture set to 2.8 (aperture-priority). Action shots are blurry due to still too slow a shutter speed. What is the next step? Is this a case, where I need camera (e.g., D300) to be able to go to an even higher ISO? It's certainly appears to be cheaper than buying an even faster piece of glass. Suggestions?