Quote Originally Posted by wickerprints


The problem with uneven density response as a function of wavelength is that you can clip your highlights in one or more channels without achieving adequate exposure in the other(s). For example, if the filter has a 10-stop density in the red and blue frequencies but, say, only 6 stops of density in green, then it becomes improbable to expose the sensor in such a way that would allow faithful capture of all three channels at once.


That's why ND filters are expensive--it is easy to make a material that blocks a lot of light, but not so easy to do it in a way that is roughly uniform across the visual spectrum.
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Technical perfection is not the point of this. That is obvious, so I thought. It Is Just An Alternative! A $4.98 Alternative for which no one should expect miracles. It's not like everyone has a daily use for a ND filter, and it is for that reason I have no desire to spend the money on one. This is just something that can be fun for someone to play around with and not have to spend a lot of money to do it. That's all, and it is cheap, and does have potential uses no matter how Technically inaccurate it might be. It's not meant to produce professional level technically perfect silky smooth waterfall photos for publication. It is something that people can do without forking out all kinds of money for a filter they will rarely use.





Does every picture have to achieve technical perfection? Can't it just be visually appealing to someone instead?