[cconstantine]

> why not put a whole bunch of filters in front of a mono camera and get much more frequency information?

Just rgb filters aren't really going to get you anything better than a bayer matrix for the same exposure time, and most subjects on earth are moving too much to do separate exposures for 3 filters.

The benefits of a mono camera and rgb filters is that you can take advantage of another quirk of our perception; we are more sensitive to intensity than color. Because of this, it's possible to get a limited amount of exposure time with the rgb filters, and use a 4th "luminance" filter for the majority of the time. During processing you can combine your rgb images, convert that to HSI and replace the I channel with your luminance image. Because the L filter doesn't block much light it's faster at getting signal, but it's only really a benefit for really dark stuff where getting enough signal is an issue.