Shooting star trails

Star trail photos can be incredibly compelling and while they take time to produce, they're probably not as difficult as you might think they are. In fact, there are two methods that you can use to capture the night sky with the stars streaking across it: a single long exposure or what effectively amounts to a time-lapse composited into a single image. This is our guide to shooting star trails.

Location

Light pollution can be a pain when you're attempting to shoot a star trail photo. If you're not able to see the stars, your camera won't be able to, either. Should you live in a city, this means looking for a location that's suitably isolated to give you a view of the sky, but isn't so isolated that you make yourself vulnerable. And if you don't live in a city, you still need to be somewhere accessible.

You also want to think about your scene. You might find that having something of interest in the foreground of your shot will improve it. Barns, dilapidated or otherwise, obelisks, and rock formations are all good starting points.

By finding Polaris and focusing on that, you'll produce a circular star trail; point your camera somewhere else in the sky and your trails will be more linear.

Timing

The best time of year for shooting star trails is definitely dependent on personal preference. How long you can manage safely in the cold is probably your primary concern. But you do need to be shooting on a cloudless night with no or little moon.

Setting up

Once you've decided on your location and set up camp with warm clothes, thick boots, and a thermos flask, it's time to set up your camera.

Camera

Set your camera on its tripod; place it in manual mode and switch the lens, preferably a wide-angle one to get as much sky in the shot as possible, to manual focus, too. Frame your shot—ideally with something of interest in the foreground—with the lens focused to infinity.

When it comes to exposure, you need to be in bulb mode, the aperture should be as wide as possible, and try ISO 1,600.

Take a test shot with a exposure time of 30 seconds; if the stars are bright and clear, you're ready to go. If it looks a little dark, adjust the exposure time until you're happy.

Camera trigger

If you're using an intervalometer, you need to set it to record as you would for a time-lapse video, using the exposure time you tested for.

If you're using Triggertrap Mobile with its star trail mode, set the exposure time that you established in testing with a two second interval between frames, and select the number of frames you want to take. You can choose a huge number of frames and stop after half an hour or 45 minutes of shooting if you're not certain how long you need to be out there for.

Hit go!

That should be about it. Hit go and wait for your camera and the universe to work its magic. Do remember to keep warm and safe!

Compilation

When you've accumulated all the images that you need, it's time to compile them into a single image with the help of some software. If you have Photoshop, that's perfect. If you don't, there are other options including the star-trail-specific StarStax.

A stack of images

Transfer your images from the memory card to your harddrive, keeping them in a single folder with their original file numbers. Whichever programme you use, this is important to ensure that the images don't get out-of-synch. The rest of this tutorial uses Photoshop to assemble your star trail shot, but you should be able to extrapolate the process to any other programme.

Import your images

Open Photoshop and import your star trail images using File –> Scripts –> Load Files into Stack. Select your folder of star trails photos, highlight all of the photos, and then select Open followed by OK.

Blending

When all of your photos have made their way into Photoshop, select all of them in the Layers panel, and then in Blending Mode select Lighten. Tah-da! You should have a star trail composite.

You can make adjustments to individual layers if you want, but otherwise, you're done and it's a case of saving. (You might want to save an unflattened PSD file and a flattened JPEG version.)

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Much of this, including all the images, is based on the fantastic How to capture a star trail tutorial found on Triggertrap's How-To microsite, and it's reproduced with permission. Triggertrap How-To is full of great content for making the most of your camera. You should take a look.

For those days when you need to be in several places at once: multiplicitous images

Multiplicity, or the art of creating images containing several yous, or anyone elses for that matter, isn’t a digital discovery. It’s something that people have been doing for decades: it's remarkably easy to achieve with film. You set up your shot and either you don’t wind on your film before re-exposing the frame with your subject positioned anew in the scene; or you wind on your film and then wind it back again in between shots. The important thing here is to slightly under-expose all of your shots in the sequence to ensure that your final image isn’t an over-exposed white mass.

If you don't happen to have a Holga lying about (they're great for creating multiple exposures), you can do it with a digital camera, too. Depending on the camera you have, you've a few options for creating a multiplicitous image. Quite a few come with a multiple exposure setting now: you determine how many exposures you want to make and the camera will re-expose the same 'frame' in-camera and adjust your expose settings accordingly to ensure that you don't end up with a too-dark or too-light image. Marvellous... if you have a camera that can do that. If not, you'll need to make friends with Photoshop, or a Photoshop-esque editing package.

Before we go any further, it’s important to remind you that achieving a great final image relies on producing a good image in-camera first. It doesn’t matter how ginormous the barrage of editing you’re going to subject your photo to, it’s got to be good from the get-go. This is just the same for a multiplicity image as any other.

When you set out to create a multiplicitous image, your starting point is your concept. Think of the story that you're trying to tell and what you need to tell it. Having a clear plan makes it so much easier when you're shooting the images because—unless it's a distinct element of the story—you need consistency in your images: furniture can't move between shots, the light needs to be coming from the same direction, and you don't want to be flapping around.

When the scene's arranged, set your camera on a tripod, adjust it's exposure settings and focal point, and shoot a 'plate' image. This is a base photo, devoid of the story's characters, onto which you'll build your final creation.

Now you can shoot your series of images containing your subject in as many different positions as your composition merits. I've found it useful to go for more rather than fewer photos; it gives you more flexibility when you compile your final image.

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When you've shot your images, import those you think you might want to use into Photoshop using the Load Files in Stacks option (File>Scripts>Load Files in Stack), which should import your images so that they are perfectly layered one on top of the other.

Next apply a layer mask to each of the layers, barring the background image, which should be the ‘empty’ plate.

Using the eye icon on the Layers Palette, toggle off all of the layers from view except Layer 1. Now brush your subject, along with anything like indentations in the chair where she or he is sitting or shadows, out of the image. It's those small details which add credibility to the unbelievable, which is what makes them important to the final composition. And while it might seem counter-intuitive to brush your subject out of the image, it isn't really.

When you’ve disappeared your subject from the scene and you’re happy with the refinement of the edges, invert your selection by pressing Cmd+I on a Mac or Ctrl+I on a Windows machine. The subject will miraculously reappear and the superfluous background will disappear.

Do take care when you're areas where overlapping occurs, because it's here where your image will succeed or fail in its realism.

Repeat this process for each of the layers, toggling them on and off as necessary to decide on which placements you want to keep, and which you wish to discard. I’d recommend saving the image as a PSD file with all the layers intact, which will allow you to revisit it and re-edit as often as your Dr Jeckyll needs to meddle with your Mr Hyde.

When you've settled on a final version, delete the layers that you don't want, save it as a PSD file, and then flatten it and export it as a JPEG image. Ta-dah!

Bazaart: easy mobile image compositing with a social side

It started as a Pinterest-based fashion catalogue, but Bazaart's users saw a different potential in the app's capabilities and were more likely to be making collages with it, and not-necessarily fashion-related ones either. Like many good entrepreneurs, Bazaart's founders spotted this trend and rolled with it; as a consequence, they started to pivot away from fashion and towards creating a Pinterest collage-maker. Since then, Bazaart has continued its movement away from fashion and away from Pinterest. It's now a fully-fledged photo editor for iOS. Bazaart is now an editing programme designed to compile composite images from those on your mobile device's camera roll, together with a social sharing element. Once you've turned your brother's head into a beer bottle or given your girlfriend a bed of butterflies, you can share your composite with other Bazaart users, diverting it into searchable channels, for example 'funny' or 'art'.

Tap on any photo and it breaks it down into its component images; you can follow people whose work you particularly like; and you can engage with other users. There are other mobile compositing apps out there, but they don't come with the social features of Bazaart, and that's what its founders are aiming for. They want people to think of Bazaart as a social Photoshop for the masses.

Since it completed its pivot to social photography in June last year, Bazaart has enjoyed 250,000 mobile downloads, and has 100,000 monthly active users who have created over 350,000 composite images using more than 2 million photos. It's free to download, but only available for iPhone and iPad running iOS 7, or at least until the end of 2014, when the developers hope to have an Android version up-and-running.