Plenty of shops will sell you a hidden camera for you to install in your home but very few will be able to give you advice based on any real world experience as to how to get the best results.
That’s why most people when they do catch an incident fine the image is useless. The two main areas that cause this are:
- Poor lighting at night
- The scene angle is too wide
Poor light is often caused by the camera it self because the budget cameras with a handful of IR LED’s around the lens causes an extreme hot spot in the scene, which rather than giving even lighting, causes the persons face to wash out. The other common factor is simply not enough ambient light. Despite what the camera specifications claim, the low light performance of any camera with a small lens is going to be poor so will require a lot of light.
The best light is a wide angle source from near the camera, pointing out across the horizontal plane as this will light up the scene and faces evenly. Try to avoid narrow beam spot lights (less than 30 degrees) and hard edge down lights such as halogens. The narrow beam will cause a hot spot and the down light will not light up the face as all the light is on top of the person head.
Other factors to consider are how high the camera is installed because as the person gets closer to the camera, too much downward angle will impact on the ability to see face details. Partially if they are wearing a cap.
The compressing used in the DVR will determine how blocky the playback image is and the frame rate affects if you get enough images of the person to work with. Compression is unfortunately something that is impossible to compare between products, without actually seeing them working. This is because the different types of compression can be implemented in many different ways. For example, H.264 is a tool kit of compression techniques. You only need to use some of them but them more you implement, the better the end image and the less storage required.