Why 30 frame limit in render settings?

I'm not usually an animator but I have recently started a project that involves short animations so I've started using the timeline for the first time in ages.
My problem is that when I try to create an anim in Render Settings the frame number appears to be completely limited to 30. I have tried adjusting the parameters and this doesn't work. How are you meant to be able to create animations with such a mean setting?
Comments
You need to adjust the settings in the Timeline pane - the Total number of frames boix.