Previously I showed how to achieve this effect in Photoshop: Fog Filter Effect for Stars in Photoshop, I finally got around to buying the physical fog filter from Tiffen, and I am quite pleased with the results!
Below you can see how the brightest stars are enhanced, and the lower magnitude stars are diminished, creating an image that is more like the human eye sees. The camera picks up much fainter stars than we can see, and our brain pays more attention to the brightest stars. You can see how much easier it is to pick out constellations with this filter.
There are some drawbacks though, this will blur your foreground considerably as well. So you will need to combine 2 exposures in post processing. One without the filter for the foreground. This isn't a big deal for me since I usually take a second exposure for the foreground at a lower iso anyways. The other drawback is the fact that you can't use this on most ultra wide angle lenses like the Rokinon 14mm, Nikon 14-24 because of the large front element that doesn't accept fitlers. I was using the Rokinon 24mm for this shot which does take filters
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