What about Megapixel Cameras?

[Numb-nuts 1]

I have not seen any discussion on here about megapixel cameras, the benefits (we can guess somewhat) and all about how they work and the methods of working out depth of fiels, sidtances to target or Focus, Megapixel lenses etc.

 

If there is a seasoned professional out there that wouldn't miind talking about this technology and giving a few minor masterclasses in this I am sure we'd all appreciate it. Any takers?

[Campbell 0]

I have not seen any discussion on here about megapixel cameras, the benefits (we can guess somewhat) and all about how they work and the methods of working out depth of fiels, sidtances to target or Focus, Megapixel lenses etc.

 

If there is a seasoned professional out there that wouldn't miind talking about this technology and giving a few minor masterclasses in this I am sure we'd all appreciate it. Any takers?

 

In relation to which camera to choose (ie 1.3MP or 10MP) its simply a price point. Once a customer sees the difference between the resolutions, it's a question of price (at least for mien anyway). And that takes care of most of the above points for me. More to the point about MP cameras is your netowrking ability. MP cameras take up significant amounts of bandwidth. Unless you've only got like 2 or 3, don't stick them on the same network as your computers or you won't hear the end of it.

[Birdman Adam 0]

Is a 1GBit network usually recommended when dealing with more than like 4 cameras?

 

Also, what is the low-light performance between, say a 1.3MP or 10MP. Do they just make the sensor larger, keeping each 'pixel' size the same? Or does the light performance go down as the MP goes up?

 

Also, I would guess that as the size of the picture goes up, you need to use a better lens so that imperfections are not noticeable. Is this true?

[rory 0]

There is a whole section dedicated to this.

Thread moved to appropriate forum.

[Numb-nuts 1]

Thanks for that Rory, my mistake.

 

My networking ability is virtually nil, therefore I think that reluctantly I will have to look for a course on networking. I have been thinking of doing an Online- CCTV BTEC course through Tavcom Training. Quite expensive, but I think in the long term I would

benefit from a formal learning program, rather than just learning as problems arise, which is way too stressful.

 

So what you are saying about bandwidth, is effectively that if a large number of MP cameras are required, then it might be better to set up several smaller LANs and link them, is that correct?

[fa chris 0]

Each camera uses a different amount of bandwidth depending on a number of factors, megapixels, images per second (ips, as opposed to FPS), compression, etc. you find all this out from using tools available from the camera manufacturer. Because of this, the design for your CCTV system will now focus on the network because this is the area you'll trip up. The cameras are straight forward, powering them are straight forward, connecting and recording them are straight forward, the transmission of the data needs to be given special consideration though.

 

For example, an Arecont AV2155 2MP H.264 dome with default qaulity at 10 IPS uses ~2.5 Mbps. An Arecont AV8365 which is a 360 degree camera at 10 IPS will use ~9.5 Mbps. Some 5MP cameras can get up to 30 or 50Mbps! It all adds up quick.

 

If you design your own security network, it's not a big deal you just need to understand the bandwidth you need and what the switches you put in the project are capable of. 100mbit ports, gigabit ports, fiber uplinks, etc.

 

If you are using a customers network, you need to start working with their IT group from day one. They need to know every location you need a network drop, and how much bandwidth is required at that location for all your cameras going back to it. They also need to know the PoE requirements if there are any. Other considerations are the IP addresses you need, and in return they'll often want the MAC Addresses for all the equipment you're going to put on their network.

 

I'm really making it sound a lot more complicated than it is... best way to learn is by throwing out a few scenarios I guess and getting recommendations or critiques of your thoughts on the design.

[Soundy 1]

Is a 1GBit network usually recommended when dealing with more than like 4 cameras?

Not really, although it's cheap enough these days it's not a big deal to go GbE over 10/100. Very, very few cameras have GbE ports on them anyway. My switch of choice for smaller installs (until recently, anyway, since it's now been discontinued) is a Cisco that has eight 10/100 PoE ports and two gigabit copper/fiber combo ports - this is great for connecting up to eight cameras, plus an NVR and NAS on the GbE ports.

 

If you figure that an "average" for most cameras is about 2Mbps, you should, in theory, be able to run five cameras on a 10Mbit hub, let alone a 100Mbit switch. As others have noted, ACTUAL bandwidth will vary greatly depending on the codec, frame size, framerate, scene, etc. I've done some real-world bandwidth testing for a client and found that while some cameras can be "locked" to a certain maximum bandwidth (quality adjusts realtime to keep it at that limit), others can vary anywhere from <10kbit to over 3Mbit (for a certain 5MP camera) depending on the scene (complexity, contrast, movement, etc.) Even with a static scene, a plain gray wall, for example, will use far lower bandwidth than a scene filled with lots of random, sharp-edged lines.

 

On the whole, the bandwidth issue tends to be greatly overemphasized when it comes to LAN connections (WAN is a whole different matter).

 

Also, what is the low-light performance between, say a 1.3MP or 10MP. Do they just make the sensor larger, keeping each 'pixel' size the same? Or does the light performance go down as the MP goes up?

IN GENERAL, CCTV cameras stick to 1/3" and 1/2" sensors - meaning yes, as the resolution goes up, the pixel size goes down, and the light sensitivity along with it. Some compensate well for this with additional processing.

 

There are a few exceptions, such as Avigilon's Pro-line cameras, which use a 35mm sensor (same as in a professional 35mm dSLR).

 

Also, I would guess that as the size of the picture goes up, you need to use a better lens so that imperfections are not noticeable. Is this true?

Correct - these are marketed as "megapixel lenses".

 

The Avigilon Pros go a few steps beyond that and use Canon EF-mount SLR lenses - some of those run into the $10,000+ range

[Soundy 1]

For example, an Arecont AV2155 2MP H.264 dome with default qaulity at 10 IPS uses ~2.5 Mbps. An Arecont AV8365 which is a 360 degree camera at 10 IPS will use ~9.5 Mbps. Some 5MP cameras can get up to 30 or 50Mbps! It all adds up quick.

Fortunately, by the time you get into those level of cameras, you're paying so much for the camera itself, that building a better network (and providing the necessary storage) is a moot point

[thewireguys 3]

 

On the whole, the bandwidth issue tends to be greatly overemphasized when it comes to LAN connections (WAN is a whole different matter).

 

I can't agree with this statement. If your doing IP MP system over 8 cameras you have to know what your bandwidth is.

[hoogs74 0]

Yes the cameras dont have Gb ports generally, however you can get switches with 10/100 and for your recorder or PC to use a GB port for all the streams to go over.

[Soundy 1]

 

On the whole, the bandwidth issue tends to be greatly overemphasized when it comes to LAN connections (WAN is a whole different matter).

 

I can't agree with this statement. If your doing IP MP system over 8 cameras you have to know what your bandwidth is.

I didn't say it didn't matter, I said it's overemphasized.

[hoogs74 0]

I have to agree. Unless you are going to start running 50 or more cameras and depends on the bitrate and quality to how much bandwidth. When for a home or small commercial i wouldnt think twice about the amount of bandwidth you will use. As you should always do your own network as not to disrupt their network unless needed to.

[rory 0]

I have to agree. Unless you are going to start running 50 or more cameras and depends on the bitrate and quality to how much bandwidth. When for a home or small commercial i wouldnt think twice about the amount of bandwidth you will use. As you should always do your own network as not to disrupt their network unless needed to.

I have clients here that can barely push out 4 D1 cameras on business internet accounts let alone a couple Megapixel Cameras .. just depends on your ISP or how much you can spend on a faster upload speed.

[hoogs74 0]

Hi Rory,

Yes that is true but i think we are going through just local not external which is what i am reffering to. But with megapixel cameras external you would use such as mine port 554 which is a lower quality stream for external viewing, but locally still megapixel recorded quality.

[thewireguys 3]

I have to agree. Unless you are going to start running 50 or more cameras and depends on the bitrate and quality to how much bandwidth. When for a home or small commercial i wouldnt think twice about the amount of bandwidth you will use. As you should always do your own network as not to disrupt their network unless needed to.

I have clients here that can barely push out 4 D1 cameras on business internet accounts let alone a couple Megapixel Cameras .. just depends on your ISP or how much you can spend on a faster upload speed.

 

Rory what does the WAN connection have to do with local recording? Even viewing megapixel cameras remotely over low bandwidth connections is possible if you use the right cameras and VMS.

[rory 0]

Rory what does the WAN connection have to do with local recording?

If you need me to answer that for you then you are in the wrong business.

[rory 0]

Hi Rory,

Yes that is true but i think we are going through just local not external which is what i am reffering to. But with megapixel cameras external you would use such as mine port 554 which is a lower quality stream for external viewing, but locally still megapixel recorded quality.

Okay so you mean local, I was going the other direction.

But regardless, I was talking about cameras that are D1 res but even streaming at CIF and lowest quality it is pushing it, the connections are that bad and thats a $150 a month for a business account here, if they want any kind of good bandwidth its around $1000 a month. With the regular accounts if lucky might be able to stream one compressed MP camera, but not a bunch of them. Remember the entire world doesnt have amazing internet.

 

Just saying.

[thewireguys 3]

Hi Rory,

Yes that is true but i think we are going through just local not external which is what i am reffering to. But with megapixel cameras external you would use such as mine port 554 which is a lower quality stream for external viewing, but locally still megapixel recorded quality.

Okay so you mean local, I was going the other direction.

But regardless, I was talking about cameras that are D1 res but even streaming at CIF and lowest quality it is pushing it, the connections are that bad and thats a $150 a month for a business account here, if they want any kind of good bandwidth its around $1000 a month. With the regular accounts if lucky might be able to stream one compressed MP camera, but not a bunch of them. Remember the entire world doesnt have amazing internet.

 

Just saying.

 

Rory the systems that have dual streams and VMS software that transcodes and/or controls the streams to the clients deal very well with low bandwidth connections.

[hoogs74 0]

Hi Rory,

 

Yes i know what you mean but with internet you get what you pay for. If the client wants to have a very good upload then they will have to pay for it. But generally even cheap internet in Australia is still good enough to push out 4 x 4CIF cameras. The megapixel cameras generally have multi streams in megapixel resolution but also have a low sub stream which is about 4CIF resolution for low bandwidth footage.