Does Higher MP give you a wider view?

[c.grex 0]

I'm just into setting up a system and I have a 3MP camera.

 

The camera has a fixed 3.6mm lens, but I have mixed results when changing the resolution I get the widest coverage at full 3MP, but as I lower the resolution I loose a bit off the top bottom of the picture, I can understand this in 1080p or 720p as these are 16:9, but I still loose a little at 1.3M.

 

Sorry if it seems a newbie question, I'm just wondering what are the best settings to use in the NVR (3TB drive, hoping to run 4/5 cameras).

[mgb 0]

Yes 3MP will cover more than 2MP. More MP will equal a larger view.

 

My thinking is always that I might as well set the camera for it full potential, pixel wise.

 

Of course in setting your nvr, you will want to make the right setup decisions to keep bandwidth down and get optimal performance.

Stick with h.264 compression and a lower framerate (8-15fps)

[c.grex 0]

I'm just setting the system up at the moment, so having a play and testing. I have just one camera and I have set that at 3mp, 15fps.

 

Thanks for the reply.

[Q2U 0]

A wider view is provided by wider lens. Like this...

 

[mgb 0]

True the viewing angle changes with the lense but you are still getting more in your shot with higher mp.

[ssmith10pn 0]

Maybe changing the resolution is cropping the image?

[mgb 0]

Yes taking a 3 MP camera and setting it to 1920 x 1080 will crop the image but either way you will still get more in the shot when set at 3MP (2048 x 1536)

[ssnapier 0]

This is VERY incorrect information! A higher resolution simply adds more pixels to the given field of view. The lens defines what is seen, the resolution defines the clarity at which it is viewed.... especially when using digital zoom.

 

Higher MP (usually over 3MP, but it is sensor dependent) resolutions generally require more light to provide a clear image too. I can demonstrate this with a Mobotix camera in my driveway if you really want me to.

[ssmith10pn 0]

This is VERY incorrect information! A higher resolution simply adds more pixels to the given field of view. The lens defines what is seen, the resolution defines the clarity at which it is viewed.... especially when using digital zoom.

 

Higher MP (usually over 3MP, but it is sensor dependent) resolutions generally require more light to provide a clear image too. I can demonstrate this with a Mobotix camera in my driveway if you really want me to.

 

Well The OP said his field of view changed so there has to be a logical explanation.

[StanLee2066 0]

Yes taking a 3 MP camera and setting it to 1920 x 1080 will crop the image but either way you will still get more in the shot when set at 3MP (2048 x 1536)

 

How is that even possible? The frame of view will be exactly the same as if the picture was at 640x480. It's just captured with more detail.

[ssmith10pn 0]

I'm just into setting up a system and I have a 3MP camera.

 

The camera has a fixed 3.6mm lens, but I have mixed results when changing the resolution I get the widest coverage at full 3MP, but as I lower the resolution I loose a bit off the top bottom of the picture, I can understand this in 1080p or 720p as these are 16:9, but I still loose a little at 1.3M.

 

Sorry if it seems a newbie question, I'm just wondering what are the best settings to use in the NVR (3TB drive, hoping to run 4/5 cameras).

 

What is the resolution of the 3MP?

That might be a 4:3 format so when you change it it crops.

Axis cameras do it.

[mgb 0]

This is VERY incorrect information! A higher resolution simply adds more pixels to the given field of view. The lens defines what is seen, the resolution defines the clarity at which it is viewed.... especially when using digital zoom.

 

Higher MP (usually over 3MP, but it is sensor dependent) resolutions generally require more light to provide a clear image too. I can demonstrate this with a Mobotix camera in my driveway if you really want me to.

 

Ok, I think I have it confused then.

I understand fov and all the stuff like a 3.6 mm compared to a 12mm lense but the thing that has me confused is just recently I was setting up some Brickcom cameras and the shot has more in it when set to 3MP as opposed to 2MP.

First instance I have cameras in the stair wells and I aimed them while setup for 3MP. I saw the whole stair landing. At some point they got set to 2 MP and I didn't see all the way to the side or top as before.

Maybe it's an aspect ratio thing?

Anyway sorry for misinformation.

[shockwave199 0]

^^ Take a look and see if corridor is an option. That fov is optimized for tall narrow views such as hallways.

 

Higher MP (usually over 3MP, but it is sensor dependent) resolutions generally require more light to provide a clear image too. I can demonstrate this with a Mobotix camera in my driveway if you really want me to.

I really want you to. Not because I disagree at all. Just because I LOVE demos of anything! Thanks, if you get around to it.

[c.grex 0]

The camera in question is a Dahua (HFW4300S)

 

And I think it's a Dahua thing, it appears that the field of view does look different at different MP's, but I think it's cropping the image, it means I have to run 3mp to get the widest view.

[survtech 0]

Yes, they will crop the image. Start with a 3MP sensor, which is typically 2048 x 1536 pixels. Camera manufacturers typically don't interpolate pixels when down-resing from 4:3 to 16:9 so the 1080p output of the camera would only use 1920 of the available 2048 horizontal pixels and 1080 of the available 1536 pixels.

 

Whether you get any cropping at other resolutions may depend on the camera mfg. 1.3MP is typically 1280x960 or 1280x1024 (depending in the mfg.). I doubt most camera mfg.'s use tricks that can minimally sample odd multiples of pixels so down-resing from 3MP to 1.3MP would probably use a combination of dropping pixels and cropping.