Right, now I’ve got your attention:
I see a lot of CCTV systems, can anybody tell me why so many cameras show so much of the sky??
Are they really expecting the above headline?
Did the system owner really ask the installer to monitor the sky?
The challenge for CCTV cameras is to capture useful evidence; as the size of the scene increases, the size of people within that scene decreases, and the usefulness of their images decreases too (bear in mind that Home Office guidelines for CCTV images to be admissible for ‘recognition of a known individual’ require us to capture their image at 50% of screen height).
So why waste valuable field of view on the sky?
To make matters even worse, the sky is often bright – to cope with the brightness of the sky the camera & lens combination will close the lens iris – this then results in what is on the ground being put completely into dim shade, and becoming a virtually useless image.
Tilt the camera down a bit.
Use a vari-focal lens and zoom-in a little; take the sky out of the scene, and fill the field of view with a useful scene.
For goodness sake – think about the image; less is more; just cover an agreed scene and deliver useful images!