Sunday, October 28, 2012

Dynamic range compression at the sensor level...

Just blogging out loud about the one artifact in digital photography that sucks - blown highlights. Well, actually less the blown highlights themselves, rather the region between the fully blown and non-blown regions that always give me a "eww, crappy digital" kind of feel that you will never get with film. Maybe the big boys and their "full frame" cameras don't suffer as much. But anyways, as I do my own audio mixing, this makes me question something....

In audio, we have limiters used in several parts of the audio chain. For example, powered speakers may have a limiter built in so as to not blow the speakers when a suddenly overpowering input signal appears, and it manages this by clipping it before passing it into the analog components. A blown highlight is similarly that, a signal that's waaay to strong and the sensor just saturates.

Again, just thinking out loud, if each individual photosite has a limiter, or perhaps even a compressor applied to the incoming signal... would it alleviate this issue? It is the same thing isn't it, trying to capture a high dynamic range signal with a limited bandwidth medium, that's what was needed back in the day.

Then suddenly, you'd think about colour balancing, and the bayer filtering, and how the individual channels will combine with compression. Mmm..... not sure. For now, till some genius invents some uber high dynamic range capture or some new technique can be used to alleviate these exposure issues, it's best to follow the old adage of exposing for the highlights, and raising the shadow regions in post.

No comments: