Shooting the night Sky can produce some awe inspiring photographs and its something I really enjoy.
Its not that difficult a thing to shoot either but there are a few basics, in terms of gear, technique and processing, you need to have sorted before you give it a go.
You can shoot stars with almost any camera but there are a few near essentials that I would recommend :
- A Digital SLR. Any one will do that can be driven from a remote release. Ideally use one with the best high ISO noise control you have, typically a full frame sensor or a modern crop body.
- A very sturdy tripod & head. Any make should do so long as it is rock solid – any movement will show.
- A cable release that you can lock onto continuous firing, a cheap yongnuo etc one will do fine.
- A torch – preferably a strong one, or a head torch with a red led option.
- A fast lens. You can manage with a slower kit zoom but a fast and wider lens is often better.
- A Thermos of coffee (bottle of wine or a 6 pack – ©Tim Poulton), warm clothes, somewhere to sit, a book.. You’ll be out in the night quiet some time for star trails, go prepared..
You can shoot stars and trails almost anywhere, even in cities with a lot of light pollution.
The further you get from light pollution and the cleaner the atmosphere , the more stars will be apparent and will show up on your photograph.
I’m lucky enough to live in New Zealand where outside of the urban environments light pollution is low and the air is clean. If you live elsewhere there are often aids (maps etc) detailing levels of light pollution, like this information for the UK.
Winter and cold dry nights are the best time to be out… Watch out for condensation on the lens and make sure you are around to rescue a camera if it starts raining….
I recommend using The Photographers Ephemeris to check out the sunset times, and especially where and what stage the moon is at. A full moon can flood the sky with light and ruin a decent star shot.
Another very useful tool is Stellarium for planning out what stars will be where and when. There is also google star maps for android etc.
Also consider foreground interest, a lake, trees, rocks , buildings all can add some interest, a shot of lines isnt always the most interesting & dynamic thing to look at without some context!
Once your at a good location set your camera up with the remote release connected, point in the direction you want ( stars rotate around the circumpolar positions so checkout the position of the North Star or Southern Cross).
Switch focus to manual (autofocus is useless here) and if you have live view use this to focus on a distant object (at 10* magnification etc) , use your torch to light it up if the light level is already low. Remember to select a high ISO here and exposure simulation with a long shutter time or bulb mode.
The camera needs to be in Manual mode or bulb mode, open the aperture up to near maximum.
If your lens has Image Stabilisation its best switched off.
Take a photo (30seconds-2min) and see how focus and framing is if you cant see through the viewfinder/live view properly. Adjust if needed.
For star trails switch the camera to continuous shooting mode in raw or with jpg without any built in processing (switch off long exposure noise reduction and all the other processing options you can).
White balance is often best set manually to sunny or tungsten depending on location, I recommend doing this even if you are shooting raw.
With Tungsten White Balance (adjusted later)
Make sure you have a decent sized memory card installed and at least 1 fully charged battery.
The general rule of thumb is the more light you capture, the more stars or trails you will see. This will typically vary between some thing like F2.0 ISO 800 to f5.6 and ISO 3200.
The larger the aperture and the higher the ISO the more stars you capture but fast lenses often have vignetting or comma and high ISO introduces noise, so there are direct trade off’s here.
Note : Comma is where a lens will render a point of light more like a comma/comet! This happens more towards the corners and is typical with fast lenses. Stopping down a little does tend to correct this somewhat but at the cost of less light captured.
Shooting star fields without trails
Stars move at about 2.5 degrees every 10 minutes around the circumpolar positions. You can calculate exactly how long you can expose for without noticing movement but the process is a little complicated, depending on latitude, pixel pitch of the sensor, focal length, which part of the sky you are viewing etc.
A simple equation for maximum shutter time is 500/focal length (in 35mm terms).
This means a 10mm (crop) or 17mm ( 35mm) lens you can shoot about 30 seconds without seeing star movement at a decent sized print.
So now we have one part of the exposure triangle , the other two just decide how many stars we will see.
Aperture can be set wide open if the lens is sharp enough and you have no foreground objects that need to be in the frame. Even then you are better taking two (or more) photographs (one for foreground, one for the stars) and blending them later.
ISO somewhere between 800 and 3200 depending on noise control and what look you want.
Use the cable release (or self timer) and shoot away.
Shooting Star trails
Set-up is similar to the above but we don’t have to be so worried about shutter time here.
There are a few things that govern star trails. Length is a combination of focal length ( longer lenses = more obvious star movement) overall exposure time and where in the sky you are pointing the camera. If you point at the circumpolar positions there is less movement than if you are pointing mid way between (as in the above photograph).
You will see more stars, and therefore trails, if you let in and record more light from them, so as with no trails, faster lenses and higher ISO combine to produce more star trails.
Combining the two you can control how many star trails and how they look.
The Feature image at the top is using a 50mm lens at f2.0 and about 50min of exposure ate ISO 800 (Canon 5dmkII).
One option for exposure is to shoot one long shot.
I advise against this because it will produce a noisy image even if you use long exposure noise reduction (which will double exposure time also).
Instead take a continuous stream of shots using continuous firing in manual mode and a cable release locked on to fire. I usually make each shot a 30 second duration as this is often the point just before bulb mode comes into play.
Fire a test shot and if it looks OK then lock open the cable release and go read a book, drink a beer, tweet how great a time your having to the www.
Tip: use your torch to light paint the foreground if there is something interesting..
A straight star shot should need no different processing to normal.
Assuming we are processing a star trail image shot with multuiple exposures we first need to blend them into a single image.
This can be done in photoshop but it is either time consuming or offers less ease of use and flexibility than other options.
There are a couple of excellent applications to use for the stacking of these images:
I use Canon Digital photo professional to batch process my cr2 raws into jpg for loading into these programs.
Once loaded and processed into one image save this and process in whatever normal fashion you prefer.
Combining the results
This image is taken with one short exposure high ISO shot (7D 10mm) and many lower ISO 30 second exposures blended in StarStax.
You can also shoot at dusk or towards dawn to provide some colour in the sky as a backdrop to the star trails, shoot a separate exposure for this and blend in later.