Fixed Lens vs Varifocal LensThere are two types of lens offered in security cameras: Fixed and Varifocal. Fixed lens are one size and cannot be changed. This is typically used in applications where you don't need to change the view angle. Varifocal lens on the other hand come with a variable size, allowing you to adjust the angle of view for any particular application. At the lower setting, let's say for example 2.8mm, the camera itself will have a wider view angle, but images will appear smaller. This is good for monitoring a large area, such as an office area or retail space. At the higher setting, let's say for example 12mm, the view angle will be smaller, but the images will be larger. This is good if you're monitoring a specific object, such as a cash register or a monitor. When determining which security camera to purchase, you will need to make the decision whether to go with a fixed lens or varifocal lens. Fixed lens cameras will be cheaper than varifocal, but if you plan on changing the angle of view often, spending the extra money on a varifocal lens will pay for itself over the longer run.