Why Do 2 Cameras that are both 2.8mm have Different Fields of View?

[badayuni92]

For one my installs the previous cameras were hi look 5mp ip cameras giving a good overall fov. Please see attached image.

The cameras were changed to the hikvision ones. The field of view seems to be much less. Granted I have moved the camera down slightly to be able to see someone's face clearly as opposed to the top of their head. Please see attached image yku can not see the step or front door.

My question is does pixels make a difference to how wide and tall an image is thay you can see. The hi look cameras had a higher mega pixel count.

If I upgrade the cameras from 2k to the 4k version am I likely to see a wider and taller image and therefore be able to see the step and door? Both cameras question 2.8mm

Thanks

 

[Dan]

FoV is impacted by 3 main factors - lens focal length, sensor size, lens aperture - so even though you have 2 cameras of the same focal length if they have different sensors or apertures the FoV will be slightly different.

We always advise checking and comparing datasheets of cameras as they will tell you the exact FoV in degrees that the camera will cover.

 

[badayuni92]

Thanks Dan for the reply.

That is what's strange I have checked the data sheets for both the 4mp hik camera and 5mp hi look cameras the fov in degrees is roughly the same. That is what is leading me to believe that a higher mega pixel camera shows a wider and taller image which means you can see more

 

[Dan]

What are the camera models?

 

[badayuni92]

Hi Dan the model numbers are

Hik which is 4mp the model number is DS-2CD2347G2-LU

Hi look which is 5mp the model number is IPC-T259H

I know in the past when installing video doorbells from ring and google. The higher pixel count does give a taller and wider field of view as it has a different aspect ratio

I am really not sure if that applies to ip cameras. It does seem though the explanation for the quite big difference in fov could be due to the mega pixel difference

thanks dan

 

[Dan]

Thanks @badayuni92

You are right that 5MP cameras usually display in a 4:3 aspect ratio rather than 16:9 of 4MP, but this should only make the FoV taller not wider.

I think, from looking at the images again, there really is very little difference in the FoV. I think what is making it look like one is covering a larger area than the other is the mounting height and the angle of the camera (the lower positioned camera has the end of the garden wall positioned much closer to the centre than the old camera position).

Also, the 16:9 ratio of the 4MP camera delivers an image that is letterbox-shaped (wide & short), that narrower vertical FoV when using the 4MP resolution may be cropping out the door step and the area directly below the camera.

 

[badayuni92]

Thanks @badayuni92

You are right that 5MP cameras usually display in a 4:3 aspect ratio rather than 16:9 of 4MP, but this should only make the FoV taller not wider.

I think, from looking at the images again, there really is very little difference in the FoV. I think what is making it look like one is covering a larger area than the other is the mounting height and the angle of the camera (the lower positioned camera has the end of the garden wall positioned much closer to the centre than the old camera position).

Also, the 16:9 ratio of the 4MP camera delivers an image that is letterbox-shaped (wide & short), that narrower vertical FoV when using the 4MP resolution may be cropping out the door step and the area directly below the camera.

That makes sense dan thanks so much.

Please can you see the attach picture. This is the 4mp hik camera mounted in the same place as the hilook one.

There Is defo a smaller fov on the hik cameras. So I guess that fits with you are saying about the aspect ratio and smaller field of view

My question is then if I upgrade to the 8k version of this hik camera will I see more of the step and door?

Thanks for your help

 

[Dan]

Hi @badayuni92

in answer to your question, probably not. the resolution increases to 8MP but the aspect ratio is still 16:9 so the image is no larger, it is just a more detailed/higher resolution image of roughly the same FoV.

 

[wacko911]

Theres a setting somewhere to remove fisheye lens distortion. It will narrow your FOV. Maybe worth checking if it's enabled on the camera with the narrow FOV.