I've been wondering if Magic Lantern could incorporate an in-camera GND filter, somehow. Obviously the holy grail would be a complete control of the ISO for the individual sensor lines, but I'm not holding by breath to see that one. :)
Then another, in theory somewhat simple option I've been thinking of, would be a custom grayscale image (a gradient, usually) applied to every video frame. Whether this sounds feasible or not, or would be way too CPU intensive, I leave for others to evaluate. Two options here:
- Overexpose and then darken with the grayscale image, but in this case the highlights would be hopelessly lost (if I've understood correctly, any digital ISO trickery would not help here either?)
- Underexpose and then brighten with the grayscale image, but in this case the shadows would be more noisy and generally of poor quality (although low ISOs would alleviate this to some extent)
This is not a huge issue since we do have real physical addon filters available after all... but the problem with the real filters is that a collection of those can get expensive, they may reduce IQ and introduce flare, and may sometimes make it difficult to adjust other filters (especially with multiple screw-on filters on a rotating lens barrel).
Any thoughts are welcome. I realize this may not be possible to achieve currently, but maybe in the near future....