NIGHT MISSION

  In a recent blog post I described some of the uses to which I put flashlights, particularly those equipped with light emitting diodes (LEDs).  In that post I mentioned that I also use flashlights for other purposes.  This post reviews one of the other uses.


  Many Sony camcorders now come with a NightShot mode which gives the camera a modest capability to record video in virtual darkness.  The NightShot mode does this by removing a filter from in front of the sensor that cuts out the near infrared (IR) frequencies.  

  Near infrared  frequencies are those that are longer than those at the red end of the visible light spectrum as shown in the image at left.  Sort of a very deep red to invisible frequencies.  As the wavelengths get longer one gets into the "far infrared" region that is totally invisible to human eyes.  Far infrared sensors are used to image objects by the heat they produce.  Such heat sensing sensors are in heavy use by the military and police.


  The NightShot mode will not image in total darkness but if there's a bit of light the mode will provide a more discernible image than the regular imaging mode will.  But what you get is a green image rather than the normal color image.  Sort of like those videos from the military's night operations.


  To provide better NightShot image quality, Sony includes a small IR illuminator that can be turned off or on as required.  These small illuminators assure that you can get pretty good NightShot video but only at close ranges of three to five feet.


ILLUMINATORS


  I've done some testing over the years of other ways to provide more near infrared illumination than the weak built-in illuminator provided by Sony.  These tests have enabled me to get some interesting video at night.


  The image below shows three different illuminators that I've tested.  The one on the left (A) is a small infrared illuminator from Surefire, that's no longer available in this form.  The middle image (B) is a G2 Nitrolon incandescent flashlight from Surefire equipped with one of their F26 red filters.  The right image (C) is a Surefire 2.5", 4-cell incandescent, flashlight from Surefire (no longer available) equipped with their FM25 red filter.

  I did some video collections with the above setups.  The video following shows a comparison of the NightShot mode with 1) no supplemental illumination; 2) the built-in Sony illuminator; 3) the small IR illuminator (C); 4) the Nitrolon light with a red filter (B); and 5) the large flashlight with a red filter (C).  It also shows what kind of video you get if in the normal video mode with the large red flashlight illuminator.  The camera used for these tests was the Sony HXR-NX70.

  As you can tell from the preceding video the built-in illuminator and add-on IR illuminator are practically useless in achieving useful nighttime video.  The advantages of these illuminators are that they are barely visible at more than a few feet from the camera.

  The tests do show that the red filtered lights really provide good video at substantial ranges from the camera.  Unless you're a member of a Special Ops team that requires full covertness, the red filtered lights aren't nearly as intrusive as a white light would be and won't reduce your night vision adaptation as a a white light would.

INCANDESCENT VERSUS LED

  For these red-flltered light applications LEDs will not work.  They emit virtually no near IR frequencies.  When you put a red filter over them there's hardly any light output.  So in this type of NightShot video application, LEDs are not the way to go.  The downside of this is the fact that virtually all flashlights are becoming LED based.  SureFire, for example, no loungers sells a large (2.5") flashlight that uses an incandescent bulb.  Luckily, they still sell replacement bulbs for prior 2.5" incandescent lights, of which I have two.

  To illustrate the range that the red-fliltered lights can provide useable nighttime video I did the following video.

  I first started using a red-filtered light with my Sony HVR-A1U.  Unlike the Sony HXR-NX70 shown in the illuminator images above, the A1U doesn't have a nice cold shoe for mounting accessories. To mount the light I devised the setup show in the image at right.  I used a couple of cable ties to attach the Nitrolon flashlight to a small adjustable mount that I could screw into the camera's tripod mounting socket.  (I no longer have the A1U so I'm showing the light mounted on my Sony HXR-MC50.)  This setup works fine as long as you're shooting totally handheld.

A REAL WORLD APPLICATION

  A few years ago we found a colony of Africanized bees in a palm tree in our front yard which needed to be removed.  The removal process is done at night so I decided to video the process using the light show in the above image.  The red light didn't bother either the bees or the bee removal crew but allowed me to create the video below.

  We're planning a vacation trip into the Amazon jungle next year and I plan to take the 2.5" red-fliltered light (C) shown above.  We'll see how good it is at capturing some of those night creatures.  ;-)