I think it depends on what kind of adaptor you're using. If you're using one for eyepiece projection (a method which you place the camera behind an eyepiece) this will result in more mangification, and you're not supposed to get the whole moon in there.

If you're using and adaptor that's meant to have an eyepiece in there, but then leave the eyepiece out, then the camera won't be at the right place for focusing (ie, the focal plane will be several feet behind your camera). So you'll need a different adaptor called a "prime focus" adaptor.

Hope that helps