Home Video Surveillance Setup - Part III (Cam Specs)

Welcome back. In this segment, I want to talk about the different specs for web cameras...

From our last session, we found out there are basically 4 types of web cams that we can choose from: USB interface, FireWire interface, Wireless Networked, and Wired Network.

There are pros and cons for each type of camera. Knowing how you want to use your spy cam will determine the type(s) you can select.

No matter which interface you choose, there will be some specs that apply across the entire spectrum of webcams.

Cost: Cams vary widely in cost. Price however, should not be your driving factor. Remember the saying that "You get what you pay for". This holds true for webcams as well. In general, the more you're willing to pay, you're likely to find more features and better image clarity. However, this isn't always true so be sure to pay close attention to features, specs, and customer reviews. Higher-end webcams usually include better imaging sensors, better lenses, and better color processing.

Resolution: This is the size of the captured image measured in pixels or dots per inch. The larger the spec, the better the quality of the video. Typical resolutions are from a low of 160x120 all the way up to 1600x1200. Standard resolution is usually 640x480. This used to be the upper end but now it's the norm. Keep in mind that each pixel is data. The larger the resolution, the larger the data flow and storage requirements are going to be. Resolution is directly proportional to speed.

Frame Rate: (or speed) is the number of pictures captured and transmitted per second. Remember video is nothing more than a series of still images. The faster the frames per second (fps), the better the video will look. At 10fps, a video looks choppy whereas around 25 fps or so, the eye begins to see the images as a flowing image. 30-60 fps is more cinema-like and looks much sharper and defined.

There is a trade-off -both frame rate and resolution are important but unfortunately, they combine to create a challenge for both your connection, and your computer. Higher resolution means more data per picture. Faster frame rates mean more pictures per second. This means that the pipe (connection) you're pumping this through needs to be able to handle this tremendous data flow. Your computer also has to be able to handle this data rush and if you intend to store it, you need to have adequate (hard drive) space available as well.

Some cameras have built-in data compression so they take some of the burden off your connection and computer by compressing the signal so there's less data to work with, but these models cost more. If you plan to use a low bandwidth connection and/or have a less powerful computer, this type of cam may be what's needed. Even though it's a bit more expensive, it's cheaper than buying a new computer.

Types of Cams:
USB Cams are the most common, the least expensive of the lot and probably come in with the largest selection. But not all USB cams are created equally. Due to our data throughput requirements, you should only consider USB 2.0 or better cams. The older USB 1.1 spec is just too limiting with bandwidth. For measurement speak, USB 1.1 has a transfer rate of 1.5MBytes/sec. USB 2.0 rates at 60MBytes/sec (40 times as fast).

Warning - pay particular attention to the USB spec wording. If the cam states that it's USB 2 "compatible" or "ready", shy away. This manufacturer is merely stating that the cam can function on a USB 2.0 connection, but in reality may only be working at a USB 1.1 level.

USB Length Limits; USB is good for cams that are located close to the computer. Normal operating distances are up to 12 feet. Anything beyond this length, you will need to install active USB extenders which repeat and amplify the USB signals. This is doable but every extension adds resistance and potential for performance degradation.

Ultimately, If you choose a USB connected camera, you'll want to make sure it's UVC-USB 2.0 Video Class compliant. No video drivers required - driverless support for UVC web cameras is built into the Mac operating system for instant plug-and-play operation. The Mac OS X has shipped with a UVC driver included since version 10.4.3, and it was updated in 10.4.9 to work with iChat.

Firewire cams can transmit higher data flows. Firewire (IEEE 1394 interface) is a serial bus interface standard for high-speed communications that transfers at speeds of 400MBytes/sec or more than 6 times faster than USB2.0.

The benefits of going firewire are speed and bandwidth. If your computer is powerful enough, you will be able to process some very nice video images with a firewire cam. Be aware that that bandwidth also means there will could be some big storage demands as well. FIrewire, like USB, is also hampered by distance. Normal cable length is under 10 feet but it's possible to extend this too with the use of active firewire extension cables but the same performance degradation is a potential issue here to - just like USB.

Network cams are great for placing cams at distances further away from the computer. These web cams hook up to your Airport extreme router (or other brand name routers) and are connected via an ethernet cable. Typical modern ethernet connections run at 100Mbits/sec. While a bit slower than firewire, ethernet can transmit over long distances - over 1600 feet. This length can also be extended but does not suffer from the degradation of USB and Firewire extensions. Also, this communication method normally does not require shielded cable. Many offices and business buildings are already cabled for ethernet. The downside is that a cable needs to be run to the camera. If your home isn't cabled as such, you will need to string the cable.

Wireless network cams work just like the wired versions but do so through a WiFi network. The positive is that these cams can be put anyplace a wireless signal is present. They can be moved at will and are gaining popularity - as a result, the price of them is starting to come down. The negative aspect of these cams is that they require a wireless network and some of the earlier models did not support very good security measures. They also tend to be more expensive than their cabled siblings and can sometimes suffer from bandwidth problems. Depending on your WiFi signal strength, you may not be able to push as much data through the air as you would like. Communications with the camera are dependent upon the quality of your wireless network signal and any surrounding electro magnetic interference.

As you can see, there are tradeoffs and compromises to each type of web camera, but now that you know how to select one and what to look for, you should have no trouble finding one to suit your needs.

image logitech quickcam vision pro for macintosh

If you are in the early stages of developing a surveillance system, I suggest you start out with the Logitech QuickCam Vision Pro for the Mac. It's my USB best pick. If you should need something different down the line, this webcam will still do a great job for iChat, WebCamNow, Skype, YouTube, DailyMugShot, and any other web cam application you want to use it with. This is a great starter/expander Apple Mac Compatible Web Camera.

If you think you might need something else, don't be afraid to look at my other BEST-OF picks in the webcam list on the Apple Surveillance Cams page.

Ok, that's more than enough for this time. Next segment in this thread will be about putting these cams together with some software... See you soon.

Home Video Surveillance Setup - Part II (Camera Types)

Web cam selection - the type and model of camera you choose for your Mac surveillance security system is THE MOST IMPORTANT part of the entire project. Not to scare you off by that statement, it's just that I want you to fully understand how important this piece of equipment is - it's the eyes to your spy system!!

When considering your camera selection, you will need to factor in a number of variables to find the best camera to meet your needs. There is a wide spectrum of products within the webcam arena, each designed to meet a particular set of requirements. It's wise to think this process through and spend some time considering how you plan to use your cams. This will help guide you in your spy cam selection.

Things to think about are:
1) How far away from the computer will your camera(s) be located?
2) Will the camera be stationary or will you want to move it from location to location
3) Are you going to want to control it remotely, either over you local network or through the internet?
4) What level of clarity will you consider acceptable for viewing?
5) Does this camera need to work in a low light situation...

There is a lot more criteria to consider but those are the biggies. So let's look at each one a bit closer.

Distance: If your cam is going to be close to your computer than you may be able to get along with either a USB or Firewire type camera. There are limits to the length of cable for each sort of webcam. There are ways to extend the length, but these sorts of extensions have limits as well. If distance is going to be lengthy, you should look at either a network or wireless cam.

Locations: If the location is going to be stationary, you will most likely be able to use a cam with a connected cable. If on the other hand, you plan to move the camera around, you'll most likely want a wireless version so you don't have to string cables all over the place. If the location is fairly distant but the cam will remain in one place, a network cam is a good choice. But then again, if running a cable is going to be a hassle, then you should give a wireless cam the nod.

Control: If some of the things you want to do with your cam involves remote control such as panning, zooming in on a particular area, or queuing in on sound, make sure the cam you select has these capabilities.

Clarity: Consider visual clarity of the video image. If you plan to use this as a Nanny cam or to watch a cash register or something critical like that, the quality of the picture captured is going to be very important. However, if you only plan to keep an eye on the pool or use one to watch the weather (or something similiar), then quality may not be that important to you. Good cams have ground glass lenses and should have the ability to perform some sort of focus functions. Focal distance is another attribute you should check when selecting a cam. Video quality is also affected by the type of connection you use to hook this to your computer. USB can get overwhelmed by the shear volume of data flow and so your frame rates will be lower than say, a Firewire or an ethernet connection. So too with the size of your cam. If you're after a tiny cam that you plan to install in a hidden devise, the small lens will affect picute quality.

Light Sensitivity: Where you plan to use this cam is something else to review: If you need to keep an eye on subject material where there is little or no light, you should think seriously about a night vision type camera. Same is true for indoor or outdoor use - make sure the camera is rated for the environment you are going to place it in.

As you can see, there's more to selecting a camera than just picking one up off the shelf. Not that this is a hard task, it's just important to do a bit of planning so you get the right web cam during the first go-around. BTW, there's no reason why should feel that you need to buy a camera with every bell and whistle in the book. If you plan to have multiple cameras throughout your system, each one can be chosen for that particular requirement. You may have a night vision cam at the front door, a hidden cam in the babies room, a usb cam watching your office area, and a remote network cam keeping tabs over the back yard.

Next time will discuss specifics about each webcam. In the meantime, you can visit the
Apple Mac Surveillance Cams page to get some feel for the cameras I recommend in each category.

See you again soon.

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