In many cases, the camera app itself offers to chose the storage for images/videos. Check its settings for an item called "storage". If it's not there, you could try to use a symlink of the DCIM folder to the sdcard.
That's a case for App2SD -- but depends on whether the apps support it or not. You can check this e.g. in Settings→Apps→Manage Apps. If supported by the app, you should be able to move it out of the "system space" from here.
As for where an app is installed by default, mostly depends on two things:
what the developer specified in his apps Manifest for the install location (see App Install Location in the developer's documentation)