Why do cameras still need ND filters?

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Obviously it was a thing for film cameras, but now that everything is digital, something like “just make the picture darker” seems extremely easy to do with software

quick edit, I know what ND filters are for and how to use them, no need to explain. it just seems to me that it could be engineered in a way that doesn’t require them, which is what I’m asking about

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Anonymous 0 Comments

Any given light sensor will have a range of possible responses, from 0-100%.

If you have regions where your sensors are giving 100% (because some are 115%, some 125% and some actually 100%) you lose the information of which bits are brightest. At that “just make the picture darker” will just turn them from all-white to all the same grey.

The ND filter gives it a -30% before it hits the sensors, and thereby means that what would have been all 100% becomes “this bit 85%, this bit 95%, this bit 70%”.

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