LP vs SP video recording

I can't find a manual for this model online.

Your manual should tell you the video quality each mode records in. The video quality then depends on how you plan to view it.

It looks like the normal HD for the camera is 720 lines. So if the LP is 480 lines then you would see a difference on a computer screen or a high def TV but not on a regular TV.

The best way to tell for sure is to shoot something in both modes and compare them yourself to see if the difference bothers you.

That model is no longer in the Samsung line and there's no specs on Amazon (they have none for sale except 3 outside sellers). So it would depend on the size of the screen it's played back on whether you saw that much difference.