What is the setting and function of Canon camera image stabilizer?

First of all, IS is an optical image stabilizer, not a photon image stabilizer.

The anti-shake mode of 80IS has four options: always on, only shooting, panning (following shooting) and off, and the effect is similar, but in the always on mode, the power consumption will increase.

Anti-shake function is not omnipotent. It can only guarantee that you can shoot normally in a place slightly darker than the standard light environment. If it's darker, there's no guarantee at all. Nikon's most cowhide VR anti-shake system can only ensure that the shutter speed can be reduced by 4 gears, while the DC anti-shake is at most 1.5-2 gears.

For example, at night, the shutter speed is very low if the flash is not turned on indoors and ordinary indoor lighting is used. At this point, the is function will have no effect. For example, if you have a fever of 38, put a wet towel on your forehead to cool down. If the temperature reaches 40, it's no use putting towels.

So don't be superstitious about the IS function.