How do I capture HD screenshots and video?

[Cartophile]

No question is stupid if you don't know the answer, so...I see all these great mods with videos and screenshots that are gorgeous. I'm playing Skyrim and have it modded up and it's beautiful but my vanilla screen capturing (or is it Steam's?) is awful (0.5GB max). So my brilliant sunbeams streaming through the trees? Not captured. My superHD textures? Are superturd textures. Anyway, you get the idea. Is there something I'm missing (app, mod, etc.)? I want to snap a photo of the sunset but all I get is a monochrome disk.

 

Also, this is clearly the wrong forum, but which one is correct? I posted here because it might not be deleted.

 

Thanks!