My Night Series : 5 quick tips to photograph star trails
I have learned the hard way. I say hard, because a lot of time and effort can go into this type of photography with some very sleepless nights. I have even sacrificed a lens when a badly secured tripod toppled forwards as a wind came up, when, finally exhausted, I had nodded off to sleep. Here is a five point system written in very practical terms and if followed like a recipe – should avoid you making all the same mistakes I did. This is what I teach my candidates on my photography internship too. I am going to assume you know the relationship between ISO; Aperture and Shutter Speed. There are essentially two methods (one photo or multiple stacked photos) and you should try them both out. I talk about both of them in my photography internship program and in this blog. Good Luck.
Star trails from the beach. Credit: James Dobson
1. Choose a suitable spot and time
It is vital that you shoot at night and in a place where there is as little ambient light (from other light sources) as possible. Do not shoot if the moon is more than half full. I usually try to shoot this technique at new moon up to quarter. You need a clear; dry night and lots of time.
2. Ensure you have all the gear you need
Things you will definitely need:
a. A digital camera with manual settings and focus
b. A lens: the focal length of your lens matters: This is simple: The longer the focal length the longer the trails. With a wide-angle lens you need really long exposures in the order of minutes for the trails to be noticed, with a telephoto lens the trails appear in a few seconds but composition becomes more difficult.
c. A tripod with something to weigh it down that will not swing in wind. If there is any movement at all your photo will be blurred.
d. A shutter release mechanism. I use an intervalometer (I have a canon and a phottix and the canon is easier to use but more expensive to buy) but many cameras either have this as an on-camera capability or you can use third party software and load it onto your camera in some cases. See magiclantern.com if you have a Canon.
e. A fully charged battery and a large enough memory card
f. A head torch but be careful where you shine it. I use this for setting up only unless I want to paint with light too!
A flask of something hot to drink and some good friends are nice optional extras.
3. Set up your camera and gear
a. Exposure time:
Make a decision on what look you want to create to decide how long you want the total exposure for all your stacked images to be: 60 minutes or over will give you a full striped effect such as this one- shot for 120 minutes between 1 and 4 a.m. in Mozambique.
the tropical night sky in Mozambique, Africa- Canon 5D mark 2 with a 15 mm fish-eye lens pointing south west – shot as around 500 RAW photos and batch edited for noise and brightness and then stacked
If you want something with short trails, then 20 to 30 minutes will be enough. These are less popular but if you don’t want to leave your camera outside while you sleep or watch TV you can still get small trails at such short time lengths. It is possible to take only one image but only if you have a super fast lens that you can open to f2.8. I Like to use this technique if I can get up with enough time to just both shoot the stars for 80 minutes and then catch the beginnings of a sunrise in the sky.You want your ISO to be low to avoid noise. If you have a new and “top end” camera then if possibly handles noise pretty well so check that out first. I use either a Canon 5D mark 2 at ISO 400 or a Nikon D300 at ISO 200. You can also download software that can get rid of noise seamlessly but that is a topic for another blog or another month in the photography internship.
b. Focus
Know what the hyper-focal distance is for your lens and your f-stop and then set your camera to this distance. If you forget to pre-check this then take a test shot and zoom in on your camera screen to check focus. Never shoot assuming what you can see as tiny pinpricks on your camera screen are in focus. If you set your camera on infinity the likelihood is that they are not. Once in focus carefully set your lens to manual focus without jerky movements that will bash this delicate balance out.
c. Compose
If you want to get a circle of trails then point your camera to the North or South Pole. If you shoot East or West you will have more of a horizontal stripe. If you’re shooting North then the Polaris (a.k.a. the North Star) is what you’re aiming for – it’s the last star on the handle of the Big Dipper, so if you find that you’re good to go. The South Pole is a bit more difficult to find, as there’s no prominent bright star near the pole to help like the Polaris. You can use free apps on smart phones or tablets or add a good old-fashioned star chart to your list of essential items.
d. Set your camera settings:
I recommend you shoot as wide open as you can with your lens. I prefer f2.8 or even f1.4 where possible. There is lots of information on the net about why if you are interested.Shoot in RAW. You can then do batch edits in your preferred software to get the colours and look you want before using the stacking plugins or applications.
where are those pesky stars. sometimes it’s a waiting game
Two methods:
1. As mentioned before you can shoot one shot only by putting your camera on BULB and setting your shutter release mechanism to around 80 minutes. Just one shot is great for landscape type shots (getting the star trails to light up the mountains below. This depends on what type of camera you have and you may have to experiment. With newer DSLR’s try ISO 400 or 640 and with older ones like the Nikon D200 or the Canon 5D mark 1 (manufactured pre 2009) try to stay at ISO100 unless you are going to download software to remove noise. You can also use your in-camera noise reduction here if you want to try it but beware the photo will take twice as long to shoot so make sure you have enough battery power. If your camera turns off due to battery running out before the shot is ended the camera will not save the shot!
2. Another method is to shoot multiple images once you have worked out the maths of how many you will need for the time you want to be shooting- and then stack them (you get apps that help you do this). For the stacking method set your shutter speed to 30 seconds if you are working “in camera” i.e. without a shutter release and if you have a release mechanism then you can open your shutter for longer. I have played with leaving my shutter open for up to 3 minutes at a time and leaving just 1 second (or as little time possible) between shots using an intervalometer and then stacking and this works well for a look with brighter star trails. I do sometimes get noise and hot pixels when I do this possibly due to the sensor heating up. If you use this method make sure you have your in-camera noise reduction turned off to avoid gaps in your trails.
4.Processing
When post-processing star-trails start with noise reduction, then adjust contrast and saturation and finally sharpen to taste. Removing noise is the most important step, and then it’s just about your taste.
Post process software for stacking
These will automatically throw all your images together and produce a stunning star trail. Image stacker is great if you can only make star trails in areas, which are light polluted.Here is s link to an action for Photoshop and please note directions as you are requested to first create an all black image as a canvas:
http://www.schursastrophotography.com/software/photoshop/startrails.html
Another real benefit to image stacking over single shots is that you have all the necessary photos to make a time-lapse video.
5.Sharing
Share the love. Show the world how it worked out (social media networking is a dream for this) and send me information about anything that didn’t. I find sharing and getting comments makes you want to try harder and get better! Come and share your experiences with us at the photography internship.
Next time in the night series: Shooting the Milky Way. Subscribe to this blog for on-going practical tips and tricks.
Fiona Ayerst October 2103
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