Monday, 16 September 2013

Star Trails Photography Tutorial

Guest post by: Gerry Kingsley

star trails photography tutorial
Photo by Gerry Kingsley

Things You Need:

Your camera needs to be able to handle these types of exposures that can span from 30mins up to 4 hours. First make sure your camera has a BULB setting. BULB allows the exposure to run indefinitely with the only limitations of your battery life. Next you will want your camera to support RAW format for the best quality of the final image. It's best to use dSLR camera's that are built with CMOS sensors as the older CCD sensors are highly susceptible to heating issues which result in pink or purple flares across the images.

Okay so your camera can do BULB and it supports RAW image files, what next? A lot of people ask me what is the best lens to use for this type of photography; well the answer is the wider the better. I use a Sigma 18-50mm f2.8 lens, don't worry you don't have to go out and buy expensive glass to create stunning star trails. A basic 18-whatever kit lens that comes with most DSLR kits will do just fine.

One important tool to have is a shutter release cable that will activate the shutter in BULB mode (unless you want to hold your thumb down for hours). Nikon wireless remotes will automatically stop the shutter after 30mins, so for Nikon users its best to have the MC-DC2 shutter lock cable (which is about $30).

Canon users can get by with their wireless remotes because it does not auto stop the exposure until the users decides to stop it. Another important thing to make sure is to have your battery fully charged prior to going out, 1 fully charged battery should be enough for a 2 hour exposure. If you’re lucky enough to have 2 batteries and a grip then you should be able to go for about 4 hours.

Now the last important tool you need is a tripod, it’s crucial you have a sturdy enough tripod, remember you will be out there for at least a couple of hours and if wind picks up you do not want to have your gear toppling over.

Conditions For Shooting:

The best time for shooting star trails anywhere will be in the dead of winter. The freezing cold air in the winter months give much more opportunity for crisp clear nights. It's important to travel as far away as you can from any light pollution. Light pollution can be seen from great distances and is caused by cities and municipalities with street lights, building lights, sky scrapers etc. This is the distant glow you see when you're driving back from out of town and heading home and the sky is lit up as you come closer to your city.

Depending on where you live you may have to travel quite a ways to be able to get far enough to avoid light pollution. Thankfully I only have to go about 20mins out of my city limits here in Northern Ontario. Okay so now you found a nice spot to do your star trails it’s out of the way from any traffic and far enough from any city.

Directions To Find the North Star:

The direction of where you will be pointing your camera is important if you want to get circular spirals. First you need to find Polaris, the North Star.

How to find north star
How to find north star

1. Locate the Big Dipper in the northern sky. Knowing how to find the Big Dipper is easy due to its large size and distinct shape. Depending upon the time of the year constellation of stars may be tipped in different directions as it rotates around Polaris.

2. As shown in the diagram, locate the two stars that form the outer edge of the Big Dipper.

3. Draw an imaginary line straight through the two stars of the dipper edge and toward the Little Dipper. The line will point very close to the handle of the Little Dipper.

4. The brightest star in the Little Dipper is at the end of its handle. This is the North Star.

5. Congratulations, you now know how to find the Polaris, the North Star.

For more information on this please visit: How to Find North Star

Setting up your Camera:

Now it’s time to setup your camera and shoot your trails. To be able to get a crisp and sharp image you will need to have your lens in manual focus and what you want to do is set your focus 1 notch back from infinity. The infinity symbol will look like a sideways 8 figure, once there; just move your focus ring back gently by 1 notch which should be defined by a line on most lenses.

For the camera's settings you need to make sure you have “Long Exposure Noise Reduction” disabled.

If this is enabled once your exposure finishes it will take an equal amount of time to save the image, so if you have a 1 hour exposure the LENR will take 1 hour to apply the NR algorithms. Noise is not a really big issue with star trails and if any, it can easily be fixed with post processing software like Adobe Photoshop CS4 or Lightroom 3.

Here are the settings I use with my Nikon D90:

  • Aperture: f5.6
  • Shutter: BULB
  • ISO: 125
  • White balance: Either Auto or Tungsten.
  • Metering: Dynamic

I found this setup works best for me. Keep in mind that based on your geographical location and how dark/light the sky is you will most likely need to fine tune your settings and it will take a few attempts of trial and error before you find the optimal settings that will yield the best results.

Once your done you may find your image has a weird pinkish color or bluish hues, I usually add a tonal contrast filter and white balance filters in Photoshop to correct colors and add more detail to the trails, mainly to bring out the faint ones.

Before Post Processing:

how to photograph star trails
Photo by Gerry Kingsley

After Post Processing:

star trails photography
Photo by Gerry Kingsley