Night Photo Quality

What makes a good quality night photo with Infrared cameras? By far if you are seeking only quality at night and have no concerns about the infrared camera being spotted by trespassers, then you should be asking about the “Red Glow” infrared. The red glow infrared has the most available “flash” but is also very easily spotted from just about any distance. WE do offer these for our X series cameras but most want the no glow infrared. So if you are wanting to stay with the “No Glow” infrared then you should know that all are not created equally.

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There are quite a few factors that go into getting a good night image but mainly the list below covers the majority:

  • Image sensor
  • Lens
  • Infrared
  • Power
  • Shutter Speed
  • Gain

Image Sensor
The image sensor is what the camera uses to actually “capture” the image.  It is what the camera uses to actually scan the image if you will. Better quality sensors have fast scan rates and processing speeds. They are more sensitive to light changes and can cover wide bands of light differences. So the better the sensor the better capability your camera will have.

Lenses
The lens plays a surprising important role but probably not in the direct way you think. All sorts of engineering specs on lenses but to keep this simple the lens have a couple differences that can make big changes on your picture. Viewing width (or angle) – is exactly what it wounds like. The width of the field of view on the lens is what sets the field of view on the camera. Wider viewing angle lenses get “more” in the picture but they also make the targets appear further away and can trick your brain into thinking your flash range is much further than it actually is. Because the target in the picture will look smaller you immediately “feel” like the target is further away from the camera giving you the false impression that your flash range is reaching out further. A lot of camera companies out there prefer the wider angle lens because it gives the camera more time to trigger and still get the target in the picture plus it appears to give a better flash range because targets look smaller.
Using a more narrow lens limits the trigger time (less field of view) but they also tend to gather more light and bring the targets closer in the picture. Keeping the targets closer can give you more detail which is important to most. Lenses that gather more light allow you to use a faster shutter speed so you get less motion blur at night. We are able to use a more narrow lens because our systems are fast enough to trigger and still keep the targets in the field view of the picture. Plus we are able to use a fast shutter speed on top of that giving you less motion blur.

Infrared
Our X series cameras use over 70 no glow infrared LEDs per camera. Powering that many LEDs over a long period of time can take a lot of power (covering that next). The number of LEDs a camera has, is extremely important on a lot of fronts. Several different types of LEDs out there but for the most part (through hole LEDs vs SMT LEDs) are pretty comparable on a per unit same type basis. If you count the number of same type of LEDs a camera has and calculate the camera’s total power output capability (battery type and size they use) you will get a good idea of the Max LED output. So if you are looking at a camera that has 20 LEDs they just are not going to have the output of one that has over 70.

Power
Having enough power to be able to properly run your LEDs is important. When you see other cameras running on 6 or 8 AA batteries with 20 LEDs you’ll understand why. The more LEDs a camera has the more power is required to fire them. That is one of the reasons why we have always used the large SLA type batteries. They are extremely durable, reliable and can provide a lot of power over a long period of time. The biggest issue when firing LEDs is they have a tendency to “sink” the battery. Sinking the batteries with AAs will run them dead pretty quickly so cameras that run AA’s don’t run their LEDs to full capacity to avoid this which means they also have extremely dark pictures at night. It takes a lot of power (capacity) to avoid this if you want to run your LEDs at their upper end of power.

Shutter Speed
This is where most out there make up for their poor infrared performance at night. The way the camera works, technically there is no real mechanical shutter it’s just a term from the past that is still used today. Anyhow, shutter speed is basically the time you leave the shutter “open” to capture the picture – the longer (slower) the shutter is the more light you can capture. So if the camera requires a very long shutter speed at night to get acceptable night pictures they will be trading that for extremely blury pictures. Pretty simply put, the longer shutter a camera has the more motion blur you have. Since we have over 70 LEDs and plenty of power to drive them our cameras can use an extremely fast shutter which reduces the motion blur significantly. This coupled with a more narrow lens gives our system a big advantage over most out there.

Gain
Gain is a term used to essentially artificially increase the brightness of a night picture (or even day pictures). So if a camera needs to have a brighter night picture they will increase the gain. There is always a natural limit to the amount of gain you SHOULD use but that doesn’t seem to stop some from using too much. See when you use too much gain to brighten a picture you also introduce what in the industry is called “noise”.  I am sure you have seen the night pictures that looked all grainy and hard to actually make out what is in them. Well that is the noise from too much gain being used. Typically, when too much gain is being used they will have to post-process the picture to “smooth” or filter out the noise in an attempt to remove the graininess in the picture. This entire process ends up making the picture appear to be slightly blurry and modeled looking in the end.

When you start really digging in to the entire process of what all goes on to take an infrared picture at night you start realizing the differences in systems. You should look for a camera that utilizes a quality image sensor, lenses, plenty of power to back the IR and operate with faster shutter and little gain. This will ultimately give you the best night images possible….

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