Monday, January 11, 2016

Increasing Star Glow

Stars over "The Fortress" - Bryce Canyon NP ~ © Royce Bair (click to enlarge images)
Stars over "The Fortress" - Bryce Canyon NP - with a Tiffen Double Fog 3 filter
The three brightest stars and planet appearing here are (L-R): Arcturus, Mars and Spica.
Canon 5D Mk3 • Rokinon 24mm f/1.4 • f/2.0 • 13 sec • ISO 3200 ~ © Royce Bair
Same as above, but with light painting add to enhance recognition. Note: although this was done
in a single exposure, the slight blurring and loss of contrast to The Fortress (from the fog filter),
persuaded me to use a second exposure of The Fortress, without the fog filter, and combine
it with the sky (see text below) ~ © Royce Bair
There are three ways to increase star glow in your NightScape photos: 1. Atmospheric conditions, such as thin cloud cover will give this effect, but this is unpredictable and impossible to control. 2. Post processing with software, i.e. StarSpikes Pro 3 plug-in filter for Photoshop. Their Soft Flare Intensity control sets the soft glow intensity around each star that you select. This process is somewhat laborious and can be a little unnatural, depending on your skill level. 3. Filtering over the lens when you shoot. The Tiffen Double Fog 3 filter gives the most natural glow of any filter I've ever used. The filter causes only the brightest stars to flare and glow, and has little effect on the dimmer stars. (It actually has a somewhat reverse effect on the dimmer stars, causing them to diminish slightly —which is exactly what thin cloud cover will do in real life.)

The are two disadvantages I find with the Tiffen Double Fog 3 filter: 1. Some ultra-wide angle lenses, Rokinon 14mm and the Nikkor 14-24mm do not accept filters; and 2. there is a slight loss in sharpness when using the filter. This loss of sharpness is most noticeable in foreground objects. In the top two photos there is a line of snow cover on the formation. This snow line has lost some definition and contrast in the image using the filter. In the two cropped enlargements below, you can see some edge blurring in the filtered image. In an image that I took that had light painting of the formation, this blurring and loss of contrast was more pronounced. This problem is eliminated by taking two shots (with and without filtration), and combining the filtered sky with the unfiltered landscape in post, albeit with some extra work.

Cropped and enlarged view of fog filtered image ~ © Royce Bair
Cropped and enlarged view of non-filtered image ~ © Royce Bair



  1. Another interesting tip! Thanks!

  2. Could you recommend other types of glow filters? Or just this one (tiffen) gives acceptable results?

    1. I've tried other fog filters in the past, and they have a blur and glow effect on all the stars, whereas the Tiffen Double Fog 3 has its effect more on the larger stars —giving an effect that is closer to real life.

      I am experimenting with some thin, black netted fabrics that I'm hoping to get a similar effect, and that can be used over ultra wide angle lenses like the 14mm.

  3. This is a great tip Royce! I haven't used much for filters but will likely give this one a shot based on this post.