Luke if you have a zoom camera i.e. with RS485 and controlled by RS485 then you can set it to one of two presets and in conjunction with a separate motion PIR set on a very narrow target (the back door) you can set the DVR to control the camera to zoom in on the back door as a alrm command "go to preset 2" for example.
The problems with this are that you have to identify a auto zoom camera that CAN be controlled by RS485.
Often the RS485 in such cameras only controls the built in electronic menu and not the zoom setting.
If you do manage to get a suitable camera, you will need to preset the back door coverage first and the
wider angle second unless you use a ptz camera, and third, setting a PIR alarm trigger will be a lot of
fiddling at the width of a doorway, you'll have to blind most of the PIR sensor using black tape to narrow the angle.
If you decide that a PIR and a indoor mini PTZ could work for you but frankly this IS probably outside your budget.
Given your other cameras, I would simply go with a single close-up view of the rear door. It's a losing battle to try
and make cameras do something they were not designed to do although very innovative and adventurous as I know you are.
If I can help with any equipment let me know.
sorry, i meant i would make it so that if the alarm system is set or part set (not to be confused with in alarm) (IE if the occupants are asleep or the house is unoccupied) then the camera would zoom in and when the alarm system is UNSET the camera would zoom out to give an overview of the kitchen.
this is because the back door is the most likely place for an intruder to break in through. i want the camera to be ready and waiting.
i have decided that an RS-485 zoom camera will be too costly though so i am going to either...
A: use one fixed dome zoomed into the backdoor and leave it at that.
B: use one fixed dome zoomed into the backdoor and another fixed dome with a wide view of the kitchen and then just switch between them depending on weather the alarm system is SET or UNSET.
C: put a 'peephole camera' on the back door looking out. but there are potentially big privacy issues which i will explain in another post.
i will PM you tomorrow. i am a bit tired right now