Checking if you've taken any direction with your NDVI project.
I'm still in gathering mode, I have plenty of time before I'll actually be using the NDVI Ag usage. Waiting for a few new things around the corner to develop in new range capture, lower cost cameras for Normalized Difference of Vegetation Index (NDVI), and new multi-capture methods. The IRMod NDVI8 is a new one, it captures additional spectrum to allow your presentation maps to display additional data, as example: differential of standing field water vs sand, or the similar non-IR reflective surfaces. Other new technology improving use of the Geo GPS sensor with 2nd camera for RGB HD 3D overlays.
Along your subject of different filters...
Had a nice email exchange with Shawn from IRMods on that very subject... filters and specialized cameras for NDVI or other out of human visual light spectrum. Basically all sensors with same sensitivity, quality, density will provide capture of pretty much all the light frequency spectrums, it depends on the sensor filters.
The key to clarification of "Filter" was seperating "Lens" filter vs "Sensor" filter. Changing the Lens filter without removing the RGB standard Default Sensor filter that's on all camera sensors won't provide any higher spectrum of light capture due to the RGB sensor filter. Specialized cameras have the RGB sensor filter removed and replaced with the filter needed to capture the desired light spectrum.
That was new to me, I thought there were multiple sensors manufactured for a certain light spectrum where instead it's basically the sensor's filter attached to the sensor. Now this excludes the extremely hi-end, ultra sensitive sensor that may be designed with intended purpose. But they still utilize the same core sensor elements, but much higher specifications.
When you pull the lens off and look at the sensor, the clear multi color film on top is the RGB filter.
If you've converted a DSLR to IR for creative work, look at it's sensor... it's a dark black looking sensor cover. If you place different Lens IR filters in ft of it, you can modify the range of IR light captured because the Sensor's filter is already filtering for IR spectrum.
Learning experience to me.... Some of the fancy hi-price Multi-Sprectrum Cameras, I'm informed are basically GoPro Sensors with different filters placed on each. Or in one design, at the back of each "lens" is the specialized IR filter and the single GoPro sensor is basically bare and each lens is using the one sensor.
So, In answer to your statement above... If you configured the Camera as a IR sensor camera with a behind the lens IR filter of new Sensor filter, you could modify the IR spectrum captured with additional lens IR Filters. With today's technology, using a internal (behind lens or sensor) filter with multiple spectrum filters, like the ones offered by several lens sites... examples: NDVI8 by IRMod
IRmods Custom converts cameras for NDVI mapping drones or the 3.37 Red, Grn, NIR Lens by Peau Productions
3.37mm f/2.8 87d HFOV 16MP (No Distortion) – Peau Productions makes using add-on lens filters not needed and it'll insure sharper image avoiding additional filters in front of lens.
By the way, the IRMod doesn't provide CGO3+ lenses, but various GoPro Lenses are the same.
If looking for NDVI lenses for CGO3+, you don't need to contain your shopping to Yuneec advertised sites, GoPro size (diamenter & thread) is the same. Although I think Peau Productions has a nice long lens mount for sale seperatley that may be difficult to find elsewhere.
