How to use a tele-converter ???

[myopia]

So, it's a 2x teleconverter. My question is whether my SLR will meter for the 2x automatically or do i have to slow/close my camera manually after a light reading?
Thanks.

 

[Big Mike]

What camera?

A modern camera with TTL metering will take into account, anything that is in the light path, because the light has to pass though it before getting to the light meter.