Many people still have old style analog cameras and DVRs. Analog cameras have limited resolution. Generally less than 1 megapixel. Some analog camera may have up to 1000 lines of resolution but most are between 420 and 800 lines. Most of our analog cameras are 800 lines of resolution.
We do still offer a number of analog cameras just for this reason. We also have plain board cameras for people who want to build there own hidden camera.