Program AE on better models will adjust for specific situations such as taping sports or twilight. Ignore digital-zoom specs. Digital-zoom numbers such as 180x or 220x are pure marketing hype, useful only for digital effects. Optical zoom is the important spec - and bigger is better. Focus on optical zoom.
Optical zoom is true zoom - it provides better images than digital zoom.
With optical zoom, you may lose some light- gathering ability as you zero in on your target, but you won't lose any resolution. Its important before you buy that you hold any model you're considering in your hands. You must tighten the wrist strap as you would in real life, then toggle the zoom lens. Ask to connect a battery to get a true feel of the weight and balance.