This maybe a stupid question... you know what, it’s definitely a stupid question.... so here it goes...
Has anyone modified a camera’s flash more specifically the casing to reduce the red glow of a camera? I noticed some brands have tinted glass for red glow now. I am wondering if there is some type of film that could break up the red blob perhaps. I’m guessing anything that’s used for modification would lower flash range.
Anyone attempt something like this before?
Pep,
This is the way many black flash cameras are made in the early days. Some have all the light produced in the low-no visibility spectrum but many produce significant light in the visible spectrum. They simply then apply a filter film over the flash that filters out the visible wavelengths. This reduces the amount of "red glow" but is pretty inefficient. The light that is produced but filtered out is energy lost.
Visibility of a flash has three major factors, wavelength, intensity, and duration. All of these play a role in visibility and how/if deer react. Most cheap cameras are very poorly timed. LEDs slowly ramp up to full intensity, hold it for a bit and ramp down. The shutter triggers during the high intensity period. More expensive cameras are much better synchronized. The LEDs turn on for a very short duration and a well timed shutter is actuated. The wavelengths in the near IR spectrum are hard for humans and deer to detect, but brightness (intensity) plays a role in detection. Brightness, of course, affects flash range ( as well as wavelength to some degree). The light produced by the flash is reflected off the subject and collected by a sensor (often CMOS). That sensor has to be responsive to the wavelengths used.
So, in a well designed black flash camera, all of these things are coordinated. I've played around with a lot of things, even using remote black flash extenders. You are right that you will likely reduce the flash range (and significantly) with a DIY filter.
I'm using older technology, but higher end cams. Most are black flash but I still have a few "red blob" cameras. With these higher end cams, the red-blob is very short duration unlike the inexpensive ones but is clearly visible. I don't have any issues with red-blob scaring deer or anything like that. The only issue I have with them is a data bias issue, so I can't use them for survey work. Basically what happens is that mature bucks learn not to trigger them. They just stay far enough away to feel safe. They keep younger deer between them and the camera. So, I often get pictures of a young deer with a mature buck on the far fringe of the flash where you can't make out much of him. With the black flash cameras, this does not happen. There is no age or sex bias introduced.
One note. All of my cameras are wireless and in permanent locations with solar panels so they run 24/7/365 for many months without human intervention. They also are a dual lens design. This means no moving lens filter or anything else mechanical that can make noise. So, the only difference is the flash.
If flash avoidance is an issue with your application, you will be much better off buying a well designed black flash camera rather than trying to add a filter to a red blob camera.
Thanks,
Jack