1.3MP vs 2MP vs 3MP Question

[mattaggie 0]

I used to think that 2MP was better than 1.3MP because it showed more detail of the imagine. But after reading about IP cameras for a few months, now I think that was wrong thinking. The 2MP does not show more detail of the same area, but shows more area (mostly horizontally). Is this correct?

 

The reason I ask, I am installing cameras in a retail store. Aisle are pretty narrow. One camera will be centered above the shelving, thereby showing 2 aisles. I should just use 1.3MP cameras as the 2MP camera would only add more horizontal space to the image, which I don't need.

 

I'm thinking to get more detail on the narrow space, I should place cameras further away and zoom in.

 

Just wanting some clarification on my understanding of the benefits of more MPs.

[riri7707 0]

My kwnoledge here :

Today, the best option is to go to 3MP cams, simply because more MP you have and more détails you get.

Even if in Live mode you do not see that.

In fact you can appreciate it when you zoom IN, in live or playback mode.

You will see the difference...

So regarding the prices today, no issues than going to 3MP.

But no much cams can provide live view or playback at 25/30 ips in 3 MP mode.

So most of them does it correctly only in 2MP mode (Full HD)

3MP at 20 ips will be used only in aereas where you need détails, that's it

 

If you can make some tests between 1.3/2/3MP, you will conclude yourself.

 

And just to make some $ economy, better to go directly to 3MP.

[MaxIcon 0]

This depends on how the manufacturer implements the resolution in firmware. There was a recent thread where one Dahua model had some resolutions that were scaled and some that were directly sampled, resulting in different fields of view depending on what was chosen.

 

Here's how it works in general, but you should check out both specs and samples from the specific model you're interested in to be sure. For instance, some older 1MP cams are more square instead of 720P widescreen.

 

4:3 aspect ratios (old style almost-square TV/monitor format):

Typically 1.3MP and 3MP.

 

16:9 aspect ratios (widescreen TV format):

Typically 1MP (720p) and 2MP (1080P).

 

On most cams, switching from 720P to 1080P will give you the same field of view with more pixels per foot, but some will trim to show fewer pixels (not too common these days). The Hik 2CD2xxx series have a smaller horizontal field of view at 3MP than at 2MP, but this is unusual.

 

Likewise, switching from 2MP (16:9 widescreen) to 3MP (4:3) will give you the same pixels per foot at a certain distance, but will give a little wider horizontal FOV and a much taller vertical FOV.

 

For example, here are the resolutions and field of view for the Dahua HFW4300S with the 3.6mm lens:

3MP = 2048 x 1536

1080P = 1920 x 1080

SXGA = 1280 x 1024

1.3MP = 1280 x 960

720P = 1280 x 720

D1 = 704 x 480

 

3MP, 1.3MP, D1 = 70 degrees H, 51 degrees V

1080P, 720P = 65 degrees H, 36 degrees V

SXGA = 65 degrees H, 51 degrees V

 

What it boils down to is to make sure you can see a sample of the resolutions you want before you commit. As riri7707 points out, a name brand 3MP cam will let you choose between the various formats and resolutions, and is usually the best way to go for flexibility.

[buellwinkle 0]

Use cameras with "corridor" mode that lets you flip 1080P 90 degrees to cover a long narrow corridor or in your case an aisle.

 

There's some nice little dome for retail you should look at. Bosch makes a tiny 5MP dome, day only but the store is lit I'm sure and it's under $200. ACTi also makes some cool hi-res domes for this situation.

[mattaggie 0]

I use Geovision software, so Im stuck using Geovision cameras unless I want to pay a license fee. That's a good idea about rotating the image. I'll have to try that. Thanks for the replies.