Nighttime photography has become extremely popular because of the excellent low-light performance of modern digital cameras. Your assignment is to head out after dark and shoot the Milky Way, the Northern Lights, and meteor showers!
The night sky is an alluring subject, but it is not an easy one to capture. Unless you are shooting star trails, you need to keep stars sharp so that they appear as points of light. To calculate the maximum exposure length for rendering them sharp, use the “500 rule”-divide 500 by the focal length you’re shooting at. For instance, 500 divided by 20 is 25, so 25 seconds is the maximum exposure you could use if you want sharp stars when using a 20mm lens on a full-frame camera. You then need to adjust the ISO for the correct exposure at this shutter speed and maximum aperture.
You will also need to research your subject, so you know when and where the core of the Milky Way or a good display of Northern Lights will be visible. Check out smartphone apps such as PhotoPills or forecast websites.
Top Tip: Exposure Blending
If you have taken two shots (one exposed for the sky and a second for the foreground), you can blend these into a single shot containing the full range of tones. Open the two files in Photoshop and, using the Move Tool, drag the lighter one onto the darker one, where it will form a new layer (holding down he Shift key will ensure they are aligned).
Click on the Add Layer Mask icon at the bottom of the layers palette. Select a medium-sized, soft-edged brush, set the opacity to between 25 and 50 percent, the foreground colour to black, and gradually brush out the top layer of sky to reveal the darker one below.
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- To get enough light on the sensor you will need to shoot at a high ISO (as high as 3200) and at your lens’ widest aperture.
- Your lens should be focused at infinity. The easiest way to do this is to find infinity focus in daylight and tape the focusing ring to keep it in position.
- If shooting the Milky Way, you need as little ambient light as possible, so a new moon is best. For the Northern Lights, some moonlight will help to add interest by lighting up the foreground.
- You will need to compose and focus in complete darkness and calculate exposures when it is far too dark for your camera to meter the scene.
- It is easy to get seduced by the beauty of the stars or the Northern Lights, but a strong composition beneath the sky is just as important as it is with any landscape. However, it is not always easy to achieve.
- A wideangle lens with a fast maximum aperture
- Sturdy tripod
- Smartphone app for predicting star positions, such as PhotoPills