I discovered a way cool trick that helps out tremendously when shooting in Manual mode or even in Aperture mode. Basically it is using auto ISO to help you freeze action at a sports game or if you are shooting handheld in low-light conditions, it prevents the camera from dropping below a set shutter speed (AKA no more blurry images).
If you’re outside with lots of light, this doesn’t matter as much. But like I said, for inside/low light it’s the bomb. In the ISO sensitivity settings menu, you can control the maximum ISO you want, say 1600. And, you can control the minimum shutter speed you want too. So for sports with super fast action, lock this in at 1/1000 or if you’re shooting your 50mm prime on your DX body, lock it in at 1/100. That way you can adjust your aperture to whatever you want and the shutter speed never drops below your minimum amount. The camera automagically calculates the proper ISO to make your exposure work out.
What’s way cool is that the camera won’t just jump full stops of ISO (like 200 to 400) it will do crazy stuff like ISO 273 – a setting you couldn’t choose to do even if you wanted to!
It’s really cool because when you move to different shooting spots or the natural light levels change all around you, you’re still nailing your exposures every time. Slick hey?
Credit for this trick goes to Scott Kelby and his Digital Photography Book 3 p.146.