The reason the videos are terrible qualilty is intentional -- Tina was one of the first (if not THE first) "latex" girls who donned a pair of latex rubber falsies and tried to pass them off as real boobs. Every single shot of her is dark, grainy, soft-focus or just plain out-of-focus to conceal this fact, because back in those days they were even less convincing than the latex falsies (i.e. FarangDingDong, Mandy Mountjoy, Zena Fulsom, etc.) of today.
Here's a shot for reference that makes it abudantly clear that she was a latex-er...