2.8mm or 4mm for this Area?

[PeteWisdom]

Hi all,

In the below picture, I have a 2.8mm installed at the corner of the ceiling, but wondering if a 4mm would be more appropriate for this angle?
Thank you

 

[Dan]

Hi @PeteWisdom

If you moved to a 4mm lens you would narrow the FoV to have less of it waisted on the walls around the camera (which can also reflect a camera's IR LEDs), but you also have to take into account that as the horizontal FoV narrows so does the vertical FoV and so you can lose coverage of areas at the top and bottom of the image.

Can you please confirm the 2.8mm model you currently have installed?
Are you planning to replace the 2.8mm model with the 4mm version of the same model?
If you are looking at a completely different 4mm model, can you please confirm which model that is?

 

[PeteWisdom]

Hi @PeteWisdom

If you moved to a 4mm lens you would narrow the FoV to have less of it waisted on the walls around the camera (which can also reflect a camera's IR LEDs), but you also have to take into account that as the horizontal FoV narrows so does the vertical FoV and so you can lose coverage of areas at the top and bottom of the image.

Can you please confirm the 2.8mm model you currently have installed?
Are you planning to replace the 2.8mm model with the 4mm version of the same model?
If you are looking at a completely different 4mm model, can you please confirm which model that is?

Hi Dan, thank you for the reply.

The 2.8mm model currently installed is a HiLook Pro 8MP IntelliSense (IPC-T283H-MU)
I am considering changing this to a 4mm using the exact same HiLook model.

 

[Dan]

Okay,

So the FoV measurements for the IPC-T283H-MU are below:

2.8 mm, horizontal FOV 119.6°, vertical FOV 60°, diagonal FOV 149°
4 mm, horizontal FOV 96.8°, vertical FOV 50°, diagonal FOV 115°

If you switch to the 4mm model you will lose about 11.5 degrees of horizontal coverage on both the left and right sides of the image, and you will lose 5 degrees of vertical coverage at both the top and bottom of the image.

So the switch to 4mm will definitely give you better horizontal coverage (with less of it wasted on the wall), but you will lose some vertical coverage at the top or bottom of the image (depending on how you angle the camera).

 

[PeteWisdom]

Okay,

So the FoV measurements for the IPC-T283H-MU are below:

2.8 mm, horizontal FOV 119.6°, vertical FOV 60°, diagonal FOV 149°
4 mm, horizontal FOV 96.8°, vertical FOV 50°, diagonal FOV 115°

If you switch to the 4mm model you will lose about 11.5 degrees of horizontal coverage on both the left and right sides of the image, and you will lose 5 degrees of vertical coverage at both the top and bottom of the image.

So the switch to 4mm will definitely give you better horizontal coverage (with less of it wasted on the wall), but you will lose some vertical coverage at the top or bottom of the image (depending on how you angle the camera).

Thanks Dan,

I will run some additional measurement over the coming days.

I am worried about IR LED reflection on the walls.