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Hmmm,
I believe in the KISS principle...
Anyone considering the "basic" mods to the DSLR may be interested in the attached illustrations.
The first shows the bare sensor response curves with the Bayer Matrix. You will see that the response curve shows a couple of interesting things....
- Down in the UV the blue and red filters still pass a reasonable amount of light.
- Above 650nm (H alpha) the red filter has a good efficiency and the green/ blue have a resonance peak - this gives quite a high NIR response.
The camera manufacturer has rightly established that the sensor needs to be:
A. Colour balanced to suppress the high red response
B. The UV and NIR response needs to be blocked to supress "bloating" effects.
Canon have addressed this "issue" with the use of the two filter system used in their current cameras.
Filter #1 (anti-alias/ dust shake) provides the (B) blocking of the UV and NIR and Filter #2 (colour correction) provides a visually pleasing colour render (A) of "family photos" as well as additional NIR blocking.
If you then multiply the bare sensor response curve by the transmission curves of Filter #1 and/ or Filter #2 you will obtain the final actual response curve of the camera.
The "Astro Mod" would remove Filter #2
The "FULL spectrum Mod" would remove Filter #1 and Filter #2
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