Star Trail and Low Light Photography
Tips on how to photograph star trails, car trails, the auruora and other night time phenomena
Use a Tripod & Remote Release
When photographing at night you will be using a slow shutter speed to capture the light source against a dusk or dark sky. A stable camera is absolutely essential for night time photography in order to avoid image blur caused by camera shake.
Much as we all hate them, its vital to use a robust tripod to get lovely crisp shots during longer exposures. Avoid skinny aluminium ones with cross bars as I'm afraid they will not be up to the job. That doesn't mean you have to spend the earth. A budget tripod in the Hama Traveller range shouldn't set you back more than about £50. Feisol a mid range brand will set you back about £250 and Gitzo can set you back anything from £350-£600 or more. Your tripod mount is also worth considering as a loose one can ruin a long shutter speed shot. As well as being robust, a ball head and camera plate allows for easier camera manipulation and control than entry tripod plastic heads, which can become wobbly and hard to lock rigid for shooting over time.
Using a remote shutter release is useful as it will give maximum control over your exposure time with an on off button. These can be purchased from most photography retailers and you now have a choice of a standard cable or on newer camera models wireless options. You can also use the self-timer on the camera up to the cameras maximum shutter time typically around 30secs for a mid range camera like a 600D. Longer exposures require a cable release and bulb mode.
Shoot in "Bulb" Mode for Longer Shutter Speeds
For the best results I would always recommend shooting in ‘Bulb’ mode using a remote shutter release; this will allow you to keep the shutter open for as long as you hold down the shutter button. Bulb mode can usually be found in two ways; one can be on your dial where you will have the letter ‘B’ along with your manual mode, shutter priority and aperture priority modes. If the B is not there on your dial then try changing your camera to manual mode and changing the shutter speed until you see the word ‘Bulb’.
Image Quality, ISO and RAW files
For high image quality shots use the lowest ISO number you can (ideally ISO 100) as long exposures can cause noise. Some cameras have a "long exposure noise reduction" control setting that is worth experimenting with.
If you shoot in RAW file rather than in JPEG, you will get greater latitude to reduce noise, boost saturation and the contrast of the lights and generally tweak your exposure up or down without damaging the image.
Night Photography Scenarios
Fireworks and Lightning
You will use a slow exposure to capture the movement of the fireworks so don’t forget your tripod and ballhead.
Plan your composition in advance as far as possible. Think about obstructions, features of the landscape, where to stand and what sort of shots you want ahead of time. Get to the location early to get a good, unobstructed position; the last thing you want is people’s heads in your shots. Factor in where the fireworks are set, wind direction and strength (especially if there is also a bonfire) and what direction and area of the sky they are to be fired into; this will help deciding what focal lengths you might want to use and to choose appropriate lenses for the show.
Try both portrait and landscape compositions are they can both result in interesting compositions. Keep looking at the segment of the sky where the fireworks are exploding this can help you to anticipate the right time for a shot as you’ll see the light trails of unexploded rockets shooting into the sky.
Lenses, Focal Length and Aperture
Try shooting at a fixed focal length at first to ensure you get focus correct and consistent. You may need to switch to manual focus as auto focus doesn’t work well in low light, it can take a couple of goes to get it spot on but try turning your focus to infinity to start with and work it from there. The fireworks are not always going to explode in exactly the same place so if you use infinity and an aperture between F8 & F16 then you have a good chance of getting nice sharp shots. Once you start getting the hang of it try different focal lengths wide angle and zooming in if you have enough lens length; if not you can always shoot wide and crop afterwards.
If you use Bulb mode you can hold the shutter button down as the firework explodes, once the explosion has stopped release the shutter button and your shot will be captured. Remember to not keep the shutter open for too long because the camera sensor is absorbing light all the time and your image can easily become over exposed; a few seconds is usually plenty. Some of the latest micro-four thirds cameras, such as the Olympus E-series, have started to introduce clever in-camera technology called "live composite" shooting modes that ignore dark areas and only exposure bright parts of an image can are perfect for this style of photography
Once you have some well exposed shots in the bag, experiment a little with your shutter speed. You can also experiment with multiple exposures using black board. Start the exposure when the fireworks start holding the piece of board in front of the lens. Every time a firework explodes move the board out of the way and you will get multiple firework explosions in one exposure for a creative arty effect.
Northern Lights and Aurora Borealis
Firstly, for these images you really need to avoid other light sources if possible. Towns and houses light pollution will decrease the intensity of the aurora you can capture on film and may mess up your exposure. Get as far away from cities as you can.If you can, find higher ground that gives you lots of directions to shoot from, if you can’t, go for a North facing view point.Take a dim torch to help you set up and turn it off and cover over your eyepiece (to stop light intruding into the lens) while your images are being taken.
Think about what you can do compositionally to add foreground interest or a focal point for your eye to rest on – it will be silhouette based so think about lines, layers shape and form and remember the rule of thirds (though rules are sometimes made to be broken)
Focus to infinity and take a test shot then zoom in and ensure your horizon and if relevant foreground subject matter is nice and sharp, you will have movement in the aurora anyway. Autofocus performs badly in low light so if need be switch to manual and use your focus ring.
Most exposure times seem to be between 15 seconds and 60 seconds. It will depend how much light there is and how good a display there is so don’t be afraid to experiment.
As you’re focussing to infinity its a long way away and you will get relatively large depth of field with a surprisingly small f number. Start at f2.8-F4 and see how you go. If you can’t get everything you need in your composition within the plane of focus then increase as necessary (increasing ISO as you go to maintain the shutter speed you want)
If shooting in AV mode Set the ISO to the right number that will give you the shutter speed you need at the f-number you’re starting at. Try ISO 400 as a starter for ten and take it from there. If you want longer exposures at the same f number reduce your ISO and vice versa. Use as low an ISO number as you can to get the best image quality.
If necessary use your exposure compensation to darken the sky – remember if you are in aperture priority mode your cameras light meter will wrongly try to brighten the dark scene to be an average mid tone. Start with minus 1 stop of light and adjust as needed. Exposure compensation will alter your shutter speed slightly so check that as you go.
For less than 2 second shots use your two second timer so your camera does not get camera wobble from depressing the shutter. I would also (once you have composed your shot as in that position the mirror blocks the eyepiece viewfinder) set mirror lock up in your camera settings which will again reduce movement in the workings in the camera.
Your camera will have a minimum shutter speed and if you are experimenting with longer exposure you will need to use your cable release in click on click off mode, to use this turn your cameras wheel into Bulb or “B” mode. You will need to shoot in manual shooting mode (M) for this and in fact you may find it easier to work in manual the whole time as that removes the issue about the camera setting the speed for an incorrect “average” exposure that you have to correct for. The only difference is that in Manual shooting mode the brightness or darkness of your exposure is a direct output of ISO + f number + speed so when you change the shutter speed or f number the exposure will go up and down directly. Take a stopwatch or use your mobile phone to time the length of exposure you need.
Star trail photography
This uses all the same principles as above except that the exposure is much longer, could be anything from 10-15 minutes or more. Some people take lots of time lapse 30 second exposures and then use image blending software to merge them all together afterwards into a composite image in photoshop.
If you want to do a long single shot exposure, experiment with 30 second exposures at a higher ISO number eg ISO 1600 until you get an exposure you are happy with, then multiply the 30 seconds by the ISO number with the two zeros knocked off then divide by sixty to get the minutes rather than seconds to take the same shot at ISO 100 to avoid noise.
For example 30 secs x 16 (if you used ISO 1600) = 480
Divide 480 / 60 = 8 minutes
Or if you used ISO 3200 it would be 30 secs x 32 / 60 = 16 minutes.
Case Study - Los Gigantes Pole Star - Tenerife
Tenerife is renowned for its clear skies, even being home to a well regarded observatory and was an ideal place to demonstrate the technique. The pole star (the fulcrum around which the star traisl will curve) was perfectly positioned above the cliffs in the evening just after dark fell.
In the first image you can see the starry sky as we humans see it, taken using a shockingly high ISO of 6400 and a 4 second exposure and then as the camera captured it over a period of 20 minutes (1236 seconds). Both shots used an aperture of f 4.0 and had long exposure noise reduction switched on.
One other thing to remember is that it will take as long to store the image on completing the shot as it did to expose it in the first place, so this technique definitely isn't something to try in a rush!
Car Light trail photography
Again using the same basic principles, this scenario involves finding a spot where you’ll see the light trails created by cars, securing your digital camera, selecting a long exposure setting on your camera and shooting at a time when cars will be going by to create the trail of light. Then its just a case of experimenting with the length of shutter speed and exposure.
Some extra tips:
- Timing/Light – one might think that the middle of the night is the best time for light trail photography (and in a busy city it can be) – however one very effective time to do it is just as the sun is going down (just before and after). If you shoot at this time you’ll not only capture light from cars, but ambient light in the sky which can add atmosphere to your shots. You also might find that earlier in the evening you get a little more ‘action’ in your shot with more cars and even the movement of people through your shot.
- Creative Perspectives – some of the most effective light trail shots are taken from perspectives other than at the height of a normal person standing up. Get down low or find a place looking down on your scene that will create an unusual angle.
- Location, Location, Location – the most obvious thing with location is that you’ll need it to be somewhere near a road – however there’s more to think about than that. Choose a location that adds interest to the shot in some way. This might be one where there are well lit buildings along the road, one where multiple roads merge together to create light trails in different directions, on the bend of a road so that the trails sweep through the image, near a roundabout so the trails create circular shapes, in the middle of dual carriageways (on a traffic island) so that you get traffic coming in two directions etc.
- Composition – the normal ‘rules’ of composition apply in this type of photography. Images need some sort of point/s of interest, the rule of thirds can be applied effectively, draw the eyes into your image using lines smartly, foregrounds and backgrounds should add to and not distract from the image.
- Camera settings – as the ambient light and speed of cars will differ in every situation there’s no single exposure combination that will work in every setting. Try starting with shutter speeds between 10 and 20 seconds (which gives cars time to move through the frame) and with apertures in the mid range (start with something around f/8). If your shots are overexposed –increase the f stop number) or if your shots are underexposed decrease the f stop numbers to let in more light through the aperture. If you want the car’s lights to go further through the frame go for a longer shutter speed and if you want it to travel less through the frame shorten it.
- Light Contamination - One thing to watch out for is letting any other light source in your image (whether it be street lights signs etc) cause over exposure - for very long exposures they can easily bleach or wash out your image altogether. Lights that burn too bright can cause distractions and draw the eye of your viewer away from subjects.
One last word on personal safety...
Ideally don’t go out alone, if you do ensure you plan exactly where you are going, tell someone where you will be and when to expect you back and stick to that plan faithfully as a safety precaution. Ensure you have your watch and mobile phone with you and it is all charged up. Take a rucksack with some water, extra layers of clothing and some emergency snacks, and if anywhere remote, a full first aid kit.
Do please wear appropriate outdoor gear for this type of shoot. In hot climes remember to take out mozzie repellent and cover your arms for biting insects. In temperate and northern climes use 4 season gear, and take extra over-layers you can add on during the night to wrap up warm as the temperature will plummet - don’t underestimate how cold you will get if you are out for a while and not moving much.
Lastly - Have a great time!