HD-SDI security cameras come in two types of HD resolutions. 720p which is 1.0 megapixel and 1080p which is 2.0 megapixel. Both resolutions offer exceptional image quality when paired with an HD-SDI DVR. The image quality is much better than what analog security cameras systems could ever dream of. With analog if you wanted to get a good image of someone entering into the front door of your business you would need a camera that was zoomed into the upper part of the door so that when the person entered through the door the camera was zoomed in on his face as he walked through the door. With HD you can zoom out and have a much wider view of the front entrance but still be able to get a much better quality image. Now that you have watched a movie in HD quality would you ever go back and start watching all your movies on your VCR. Most likely not.