Webcam "Optical Resolution" makes a significant difference to video quality

I have found that camera quality can make a big difference to video quality, and that video quality is not necessary related to cost.

I have tested two cameras, one which claims to be “Full HD video (1080p at 30fps)”, but when I check the specifications it says " Frame Rate (max) 30 FPS @640 x 480". The video quality from this camera is not a good as another 1080p camera, which states “Full HD 1080p video calling (up to 1920 x 1080 pixels); 720p HD video calling (up to 1280 x 720 pixels)” and specifications say “Frame Rate (max) 30fps@1920x1080”, both cameras are made by the same company.

A friend recently purchased a cheap Full HD camera, and though it was not as expensive as most, I am just amazed at how good the video quality is.

I believe it is real “Optical Resolution” and not “Interpolated” that makes a big difference. An optical resolution of 3MP or greater.

If anyone has experience in this area, please comment.