Pan, tilt and zoom (PTZ) cameras are a great option for monitoring large spaces because they allow you to remotely adjust their position and zoom in and out on objects of interest. This flexibility, along with the convenience of pre-set tours – where the camera alternates its field-of-view between two or more areas of interest – make PTZ camera systems a popular choice for many live monitoring and commercial industrial applications.
If you’re in the market for some PTZ cameras, what follows will hopefully help you make a more informed choice. IP camera technology is constantly evolving and there are some exciting PTZ camera features you can take advantage of for better quality surveillance video.
Before we dive into those, however, let’s consider some basics, like how to determine the optical zoom range you need.
Determining focal length, resolution
If you’re capturing video outdoors, I recommend using Google Maps to measure the distance between where your camera will be mounted and where you expect to identify an object. Once you know that range, you can search for a PTZ camera with a focal length that meets your requirements. The optical zoom of a PTZ camera (for example, 20X, 30X, or 40X) refers to the maximum focal length divided by the minimum focal length.
For example, a camera with a 4.3mm-170mm lens has 40X optical zoom. (170 / 4.3 = 40X).
If you need to capture sharp video of objects at a distance, I recommend looking for a camera with an HD sensor and at least 2 megapixel resolution. HD sensors with long-range PTZ lenses can provide amazing clarity, even from hundreds of feet away. Check out this example of a PTZ camera with a 3 megapixel sensor and a 40X lens. It can easily capture a license plate at a distance of 650 feet (198 meters).
You can learn more about PTZ camera zoom performance and the various form factors available by doing a bit of online research. For a brief rundown of the extras – including some of the more valuable PTZ camera features – we’ve compiled a short list of our favorites here:
High-powered IR LEDs If you need to capture video at night, consider a PTZ camera with high-powered IR LEDs, which can illuminate objects in total darkness from a considerable distance away. Check out this example with March Networks’ ME3 Pendant IR PTZ:
The video on the left displays what the camera has captured. The video on the right is the actual camera itself, showing when its IR beams switch from high to low.
This particular camera has a 40X zoom lens, and the ability to switch from wide angle to long-range IR automatically, depending on your zoom length. I like to think of this feature as similar to my car’s headlights. I’ll use my low beams if I’m driving at night with ambient lighting from streetlights or other buildings, but I’ll flip on my high beams if I’m driving in total darkness. This camera does a similar switch automatically, and adjusts the IR light for you. Without this type of auto adjustment, your PTZ camera’s IR could overexpose objects closer to your camera, or underexpose objects at a distance.
Auto tracking Auto tracking in PTZ cameras is nothing new, but in recent years, the technology has improved, making it much more effective at tracking objects of interest. Today, you can configure your camera’s auto tracking for objects of different sizes – small, medium and large, for example. You can also set the camera’s tracking zone, and the amount of zoom you want, all of which helps with tracking accuracy.
Electronic Image Stabilization (EIS) PTZ cameras are often mounted high on top of buildings or poles to capture a wide area of interest. If you’re going to use your PTZ camera in this way, you should look for a camera that has Electronic Image Stabilization (EIS). This feature can stabilize the camera, reducing visible vibration and blurring, especially in windy areas.
Just be aware that EIS does slightly crop your field of view in order to give the camera a zone to focus on, so be prepared for that.
Additional redundancy Pan, tilt and zoom movements require a little extra power, so most PTZ cameras come equipped with a 24 Volt AC power input. With some camera manufacturers, there’s an additional benefit for PTZ cameras supporting Power over Ethernet (PoE). If you run a 24 Volt AC cable with your camera’s PoE cable, you can ensure additional power redundancy. If the power goes out on one cable and you have a battery backup on the other cable, the camera will automatically switch over to the secondary input. With March Networks PTZ cameras, this switch happens seamlessly, ensuring zero downtime. It’s a great way to ensure your video is always protected, especially if you’re in an area that experiences frequent power outages.
High Dynamic Range Capturing surveillance video in areas with both bright sunlight and dark shadows is challenging. If this sounds like your field of view, then I suggest looking for a PTZ camera that uses High Dynamic Range (HDR).
HDR extends the dynamic range of the camera by taking two separate frames – one with a short exposure and one with a long exposure – and combining them in real-time into one image with the best balance of lighting possible. Essentially, HDR merges the highest-quality parts of two exposures into one image.
See the difference here with these two images. The image on the left was captured without HDR, while the one on the right uses HDR. You can see much more detail in the shadows in the HDR image and even the background is better illuminated.
There are many different options for PTZ cameras, and this blog article touches on only a few camera features. If you have questions about any of these features, or IP cameras in general, or you want to make a comment, post your feedback below:
Stay in the loop! Subscribe to our Intelligent IP Video Blog
Subscribe to March Networks eNews