Pictures of equipment in the near infrared spectrum
I use my modified Canon 1000D for years now to get pictures in the near infrared. I removed the internal filter from the camera. So the near infrared light can get to the sensor. In this article I write about the idea and how I take the NIR pictures.
My galery of infrared pictures can be found there: Infrarotaufnahmen von Ripperkon
Why taking NIR pictures?
For normal photographers creativity can be a reason to do infrared photography. For astro photography this techniqe is also used. I mainly started to get into it, since I wanted to get an impression on infrared camouflage of fabrics and colors. Because if you add a IR filter to the lens, only the light with a specific wave length will arrive at the sensor. I still use my old Canon 1000D. I do not know how much light IR light can travel through the Sigma lens. But for me it seems like it passes a lot of the infrared light.
Sadly I also can not tell to which exact wavelength the Canon sensor reacts to light. But if you check Google for ‘Spectral Response Canon’ you can find some interesting graphs and data. Canon also offers special sensors, that are made for NIR. Because the normal Sensors are made for RGB (Red Green Blue) and therefor not optimal for infrared. This is why the ISO and exposure time needs to be longer. So these NIR pictures can be taken at day, since there enough light is available. But the camera does not magically turn into a night vision device. Because the sensors are not sensitive enough. It is important to mention, that this method of NIR photography is not a scientific approach to measure the NIR reflectance of fabrics. It is more a cheap and improvised technique to get a rough impression.
Of course you could take a night vision device and just look though. But if you want to show pictures in the Internet, you would need to take a picture through the device. But this limits the possibilities and the resolution and quality of the picture can be lower. While the modified camera makes a high resolution picture with good quality.
And at day it is a lot easier to take pictures of different products at day and in infrared, than it is doing it at night in darkness. Here as an example is a picture with different products.
NIR Filter 950nm
The manufacturer tells, this filter only allows light from 950nm to pass. When hold against the sky, there is no light for the naked eye. You only see the reflection. But that should have been self-explaining, since this wave length is not visible for the human eye. Cameras from the mobile phone usually can see some infrared light. But here the environment is too bright.
With the 950nm filter, only little light reaches the sensor. The sensor makes a violet picture. The adjustments of the camera can tell you how little light comes to the sensor. I needed to adjust ISO to 1600, aperture to 2.5 and exposure to 4 seconds. Here the picture without editing it.
Infrared Filter 720nm
With a 720nm filter more light arrives at the sensor. With the naked eye you will also recognize some red. And I have choosen a NIR filter from a known company.
Because of the red light you can also adjust the camera settings. So now the sensor sensitivity is ISO400, aperture 5.6 and an exposure of 2 seconds. The picture turned red. Here the picture without editing it.
Editing the pictures
Every camera sensor at first catches a raw picture with the adjustments of the camera. The picture will then be saved to the camera with a selected picture style (like a preset) as JPG or you safe the RAW file and edit this later. Normal photographers edit the pictures for the effect and look they want. Or they try to make it look realistic. Because the camera does not take the picture 100% like the human eye can see the scene. So editing the picture is necessary to achieve a look or even to make it look realistic. For the NIR pictures I remove the colors, add sharpness and add some contrast. As long as nature is on the picture there is always a good comparison possible. Because in the NIR for now we mainly focus on the NIR reflectance. And we do not differ between exact wavelengths. But for printing modern NIR camouflage patterns the reflection of the colors is checked for different wavelengths. Usually they are displayed in a graph. When photographing, we have a mix of the wave lengths in the picture. The sensitivity of the sensor can also vary on different wavelengths. So this topic is not a simple as it seems on the first look.
To take a picture with a non-modified DSLR and edit it in a way, that looks exactly like an NIR picture, is not possible. Since the standard cameras do not have a special IR sensor “cell”. So it can not be simply changed in Photoshop afterwards. And a software can not guess the IR-Reflectance of a fabric just from a simple picture. Here a comparison picture from a “normal” camera and the modified camera with 720nm NIR filter. Especially the gloves tell you, that the color is almost the same. But in NIR they have contrast.
In my opinion a NVG-like look is useless. But it could be used for creative creations. For me it is still not suitable. Since it is about the difference in reflection.
Comparison between 720nm and 950nm
Here now the two pictures from above with an edit I like to do. So you can compare these two. The picture quality on the 950nm version gets lost, since the camera has got other settings. This is why I prefer to take my pictures with the 720nm filter, since they are still accurate enough.
Comparison to NVG
For the german company TACWRK I once did a video about Infrared. In this video I have some comparison of a NIR picture and a video though the night vision device.
Also I made a video about Kreuzotter Camouflage, where I added a comparison of a digital night vision camera and a real night vision device from Act in Black.
From the experience I made until today, I can confirm that a modified DSLR is indeed capable, to tell about the NIR camouflage capabilities of fabrics. Here the super dark signature of the Striker X pants and the super bright signature of the standard 3D leaf ghillie suit is easy to recognize. I was able to cross check these signatures with several night vision devices.
I collected the pictures I took in my NIR gallery. In the description I try to name as many products as possible.