CAPTURE

Imaging NLCs on your smartphone

Coax your phone’s camera into low-light mode and catch ethereal noctilucent clouds

Over recent years, the low-light imaging capabilities of smartphones have improved greatly. It’s also encouraging to see manufacturers actively promoting phones based on their performance under low-light conditions. Not all smartphones are created equal of course, and older models may still struggle to grab anything out of the darkness. This is also true of current models, not all of which put a priority on low-light capability.

For those brands which offer good night-time sensitivity, the cameras found on their phones are quite capable of imaging atmospheric phenomena such as the aurora or our ‘Capture’ subject for this month, noctilucent clouds (NLCs). If present, NLCs can vary in brightness from just about visible to making you wonder how anyone can ever miss them. Bright displays may register using the automatic functions in your phone’s camera, while dimmer ones may need a bit of fiddling to get something recorded.

Many smartphones have advanced photographic modes, offered under a ‘Pro’ setting. These allow you to tweak the camera’s settings, adjusting core values such as ISO, exposure time, and white balance. In addition, there are apps available which may offer a better low-light settings interface.

The technology in some phones is truly remarkable, offering processes such as dynamic image-stacking as standard. Here, you can take a multi-second exposure of a low-light scene while the camera is handheld, and the final result is free of hand-shake.

Traditional approach

If you prefer a more purist route, an inexpensive phone mount allows you to attach your smartphone to a standard tripod and carry out long exposures without the worry that you’re wobbling the phone or that software is ‘adjusting’ the end result.

The field of view through most smartphones is wide by default and this is excellent for grabbing NLC displays. Some models allow you to select even wider views, but here you need to be careful that all of the settings and features offered under the ‘standard’ wide view are also in the super-wide setting. The same is true for narrower field settings that allow you to get closer to the action. Here, it’s wise to stick to optical zoom only, avoiding the digital zoom functions. Optical zoom gives you a truly magnified view while digital zoom is a software resize of the image, something you can do yourself once you have downloaded your images to a computer.

File formats are important too and if your camera offers lossless formats for storage, we’d recommend using these, as ‘lossy’ formats such as JPEG mean that a lot of processing goes on to reduce the file size.

When it comes to NLC displays, the beauty of a smartphone is that it’s easy to set up, easy to carry to a preferred observing site, and easy to operate.

Equipment: Smartphone and holder on a tripod

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Step by step

STEP 1

To work out your phone’s night-scene imaging capability, try to capture a photo of the night sky under deep twilight and night conditions. Try your phone on automatic mode (some models can detect dim light conditions and adjust), on a dedicated night mode, or switch to manual mode and adjust the settings yourself.

STEP 2

Some cameras have amazing short exposure, registration and stacking functions, which allow you to record a night scene while the device is handheld. The results can be very impressive. Also consider purchasing a low-cost phone holder, which can be mounted on a tripod. Typically costing under £10, a phone holder will ensure your phone is stable for any length of exposure.

STEP 3

Pressing a screen shutter button will probably wobble the camera, but there are a couple of ways around this. You could set the shutter delay function, the one used to take group shots with you in them. Alternatively, you could try wired headphones with a volume control: when these are connected to your phone the volume increase button often acts as a shutter release.

STEP 4

If your phone camera doesn’t offer a ‘Night Scene’ mode, another way may be to adjust the camera’s settings using either a ‘Manual’ or ‘Pro’ mode, or by using a third-party app to control its settings. Increasing ISO and exposure length are the two main phone adjustments, with the option to manually set the focus at infinity.

STEP 5

If an NLC display appears, identify the brightest part and aim to capture that first. Adjust the camera settings to give you a result that shows detail but isn’t too noisy. You may need to reduce the ISO while increasing exposure. If your camera has a noncompressed format, eg non-compressed TIFF, opt to use this.

STEP 6

If you succeed, think how you can add interest to your shots. If there’s a body of water nearby, perhaps attempt to photograph NLCs above that and capture their reflection too. As ever, make a note of when and where you took the shots, and consider sending them into an organisation such as the BAA.

Send your images to: gallery@skyatnightmagazine.com

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ALL PICTURES: PETE LAWRENCE