Sunday, June 15, 2014

Look to the foreground in Milky Way Photography





The Stars are not Enough
We are getting into the best season for Milky Way photography as the galactic disk gets higher in the sky at earlier hours.  Given the

Ancient Oak , Alyson's Orchard, Walpole, NH
fact that most humans now live in cities where light pollution obscures the galaxy, it shouldn’t be surprising that most people have never actually seen the Milky Way. Most star seekers have to travel far from city lights and then, to the unaided human eye, the Milky Way is still just a cloud-like band without any clear perception of the 400 billion of stars interacting with patchy collections of galactic dust.  Just a few years ago a picture showing the magnificent band of light and dust spreading across the night sky was a unique experience for those in the country as well as the city, but new digital cameras with highly sensitive sensors have radically changed our ability to look deeply into the night sky. Now the brilliance and complexity of the Milky Way has become relatively easy to capture and it has become the necessary target of most star field images. The fact that we can now easily see into our galactic disk is still a reason for profound wonder, but a bright and clear image of the Milky Way is no longer sufficient for a memorable picture.  The bar has been raised and now the essential additional element is the foreground.

The easiest part of night photography is the capturing of the Milky Way.  There are many great articles on the web that discuss the

Milky Way in My Driveway
necessary equipment and techniques and I need not go into detail here. Mike Blanchette is a master of night photography and his article in the New England Photography Guild’s blog covers all the basics.  All that is required is a camera with reasonable low light sensitivity, a tripod and a fast wide angle lens.  I use my Canon 5D mark II with the Canon 16-35 mm f2 lens.  Locating the Milky Way is also a simple task.  Smart phone apps can locate the galactic disk at any time and location.  I currently use “Sky Safari”, but “Stellarium” is another good option.  Finally, it is a matter of finding a location with reasonably low light pollution.  I typically shoot with an ISO of 3200, and, with my lens at 16mm and wide open at f2. I find I can capture the detail in the Milky Way with a 20 second exposure.  Longer exposures would allow a lower ISO and less noise but even with the wide angle lens, the stars begin to smear out as exposures increase.  The Rule of 600 (600/focal length) is often used to find the maximal acceptable exposure.   With a 16 mm lens, the equation would suggests that I could get away with a 30 second exposure without noticeable smearing, but I have found that 20 seconds works better to get sharper, pin-points of light.

This time of year getting the best view of the Milky Way requires getting out in the early hours.  Last weekend I dragged my old body out to Dublin Lake in Dublin, New Hampshire between one and four in the morning.  My goal was to capture the Milky Way rising above Mount Monadnock from across the lake. I had used “Sky Safari” and “Photographer’s Ephemeris” to find the best location. The night was perfect, a clear sky, comfortable temperatures and only the occasional tractor trailer rumbling by.   Sadly, I couldn’t convince any of my lazy friends to accompany me but the night was lovely and for the most part peaceful along the lake.  I found a nice pull over on Route 101 and settled in.  The Milky Way was right where it was supposed to be and the moon set precisely on schedule just after one AM.  I was able to capture a clear view of the Milky Way.

The Foreground

Chesterfield Steeple
Easy, but the problem was in finding a nice foreground to add interest to the images.  I was hoping for a windless night and a glassy lake to allow for a clear reflection of the stars, but sadly the breeze persisted and the ripples obscured any chance of mirrored magic.  The lake bank was steep with little of interest to include in the foreground.  There were very few lights across the lake except for one powerful beacon that appeared, for no particular reason, to be illuminating someone’s dock.  I was initially annoyed with the beacon and was planning how I would remove it in post, but then I decided to include it as an anchoring element in my compositions.  The light and its reflection across the water, combined with the framing trees to draw the eye to the Milky Way as it moved over the distant Mount Monadnock. 


I was tired but happy with the results as I headed home with the first glow of dawn at about 4 AM, but the experience reminded me once more that the Milky Way is no longer enough for a dramatic night sky image.  It is really all about the foreground, its interest, lighting, and how it complements the arc of light in the sky.  Given this new imperative there are a number of things to consider as you approach a night of galactic photography.

Find Your Foreground
In planning your location it is important to consider both the position of the Milky Way in the sky and the placement of

Great Stars _ No Foreground
interesting foreground elements in front of the band of light. Last week I knew that the Milky Way would be moving from southeast to southwest. I hoped to catch a nice starry reflection with Mount Monadnock in the background and, as I scanned the map, Dublin Lake seemed the best choice.  If you are lucky to be on the coast you may use a light house, a quiet harbor or the rocks and surf on an isolated beach for your foreground.  As you are looking out to sea, coastal skies also greatly reduce the problem of light pollution.  Those of us who are land-locked must contend with the seemingly unavoidable horizon glow and look for other subjects including barns, church steeples, or even a sadly stripped ancient tree.  Regardless of your location, the key to foreground selection is to remember that you will likely be using an extreme wide angle lens and, to provide any impact, foreground elements will need to be quite close.

Focus Stacking
The combination of wide open apertures and the need to focus at infinity makes it essentially impossible to keep nearby subjects and unimaginably distant stars in focus in the same image. This can be a problem even with the expanded depth of field with wide angle lens’. The solution is to grab an image focused on the foreground to blend with your star frames.  The contrast between foreground and sky is usually quite stark making focus stacking relatively easy when you get home.  The contrast between sky and foreground can also be enhanced with a little creative light painting.


Light Painted Barn

Light Painting the Foreground



Old Faithful, Yellowstone
Without some illumination foregrounds often appear only as silhouettes. Sometimes the light comes naturally from the moon or surrounding illumination, such as the Lodge lights at Old Faithful.  I often use my headlamp to paint the foreground and I find that even a brief touch of artificial lighting can make a surprising difference.  The duration of the lighting depends on the distance to the foreground and the intensity of the lamp.  For nearby subjects a weaker lamp allows for finer blending, but experimentation is the key.  I try to avoid overdoing the brightness.  For me a bit of subtle fill works better than unnaturally brilliant illumination. I strive to match the soft lighting I would expect to see from a full
Pillar of Light
moon. Because the foreground images will generally be taken separately, color balance differences can be adjusted later during the stacking process.  On Dublin Lake I struggled with my light painting.  It seemed that every time I took a shot a truck came through bathing the scene with intense illumination.  I never found a light painted image that seemed just right and I ended up with the trees mostly in silhouette. In some sense I think the dark trees created a frame which nicely contrasted with the beacon of light across the water. At least it worked for me.




Dublin Lake Beacon, Mt Monadnock





Ok.  All of this discussion can be distilled to a single maxim; "Place something interesting in front of the Milky Way in your night sky shots".  So get out there and experiment, and remember to take time to enjoy the night.  The Milky Way is about 110 thousand light years across and it isn't going anywhere soon.



Jeffrey Newcomer
Partridgebrookreflections.com

7 comments:

  1. Great article. Have you ever tried to shoot the milky way from the top of Mt. Monadnock?

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  2. This comment has been removed by the author.

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  3. Great post. Foreground subject, as you mentioned, is the key to great night shots.

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  4. Would you like a lovely wife from Ireland to go sky watching love the little house in the golden dawn light. Can I please paint it on my wall? Blessings. Jsnnie

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