I've read in some photography site and found out that you can spot meter even if your slr/dslr doesn't have spot metering functions.
Only applies for zoom lens though.
"Note, however, that partial metering is very much like a fat spot meter - you can use it in a similar fashion in many cases. Also, if you have a zoom lens you could zoom in to your metering point, meter with the partial meter, and then zoom out. The result is that you’ll be metering from a small area, just like a real spot meter."