Lenses & vertical field of view

[danair]

I have a long driveway (12-14 metres) with a side door right at the end. I want to put a camera above the door facing down over the door and out towards the street. I need help selecting the right lens size. The camera I have I mind is the 2342 turret.

My first thought is to get a 6mm lens since the driveway is long and narrow. However I'm worried that I need to get the door inside the field of vision.

If the horizontal angle of vision is around 45 degrees, and the aspect ratio is around 16:9, does that mean I'll get 9/16 of 45 degrees (27 degrees) on the vertical?

Any recommendations?

 

[SyconsciousAu]

A lens calculator will help work out those angles for you.

http://www.theiatech.com/calculator.

You have correctly identified that it is difficult to cover something close to the camera and still get good pixels per metre at a distance from the camera. You have a few options.

Abandon the idea of trying to cover both. Get a 2.8 for the door and accept that you will have detection only coverage at the end of the driveway or get a 12mm and have no coverage at the door.
Use hallway mode which flips the image on it's side so your horizontal field of view become your vertical.
Put in two cameras.

The latter is the only one without a compromise to be made.

 

[danair]

A lens calculator will help work out those angles for you.

http://www.theiatech.com/calculator.

You have correctly identified that it is difficult to cover something close to the camera and still get good pixels per metre at a distance from the camera. You have a few options.

Abandon the idea of trying to cover both. Get a 2.8 for the door and accept that you will have detection only coverage at the end of the driveway or get a 12mm and have no coverage at the door.
Use hallway mode which flips the image on it's side so your horizontal field of view become your vertical.
Put in two cameras.

The latter is the only one without a compromise to be made.

That's great advice, I really appreciate the thorough reply.

The door is the priority so I'll probably go with a 2.8mm or 4mm for now and I can add a 12mm later if I think it's needed.

 

[Kawboy12R]

Definitely good advice. Pick a job or two for a camera but there are limits. The trick is identifying the most important job like you did and then testing what else it will do that you're happy with and adding specialty cameras with more specific jobs after that.

 

[Kamalas]

In lieu of posting to a more suited/visited forum post on this subject; I found this FOV calculator. For a Noob like me it helped a lot and had more sensor sizes.

Quick Start....
Enter lens focal length and distance.
Then tick one in the below section and enter custom value.
For me, (4) Sensor size. 1/1.8" which is usually not available on other lens calculators.
Dont forget to hit the Compute button.

http://www.scantips.com/lights/fieldofview.html

(a Compute button, should be more of it.)

 

[danair]

Thanks to everyone who has responded, I really appreciate it.

I would like to have the option to use the camera in "corridor" mode, however under Image settings I can see the Rotate option, however the only option is "OFF". Does anyone know what I'm doing wrong. This is the same on my 2342 and my 2142.

Thanks again.