Peter Hainsworth, from Sony, explains the best ways to go about Astrophotography.
Astrophotography is one of the most frustrating, rewarding and addictive forms of photography I have ever undertaken and encompasses many different disciplines which will grow as you perfect your skills. From experience, even before start taking a camera out of its bag.
1) Make sure you are warm – If you get cold you will loose interest, this includes good pair of shoes / boots
2) Know your environment - know where any potential trip hazards are located, I know from bitter experience having travelled to a dark site only to stumble into the edge of a pond!
3) Ensure the camera battery is charged – if it is very cold the battery will not last as long
4) Take a torch with you – a head torch is perfect, especially if it also has red LED’s built-in, (Red light is a lot more forgiving on your night adapted vision).
What will be useful to take astrophotos:
- Camera – I’ll say more about the settings in a moment
- Lens – the focal length depends upon what you wish to try and capture, but for general star trails a wide angle lens of around 28mm would be perfect, (remembering the Alpha 35 due to the APS size imager does give a 1.5x magnification). I would strongly recommend the lens hood (Light shield) is fitted to the front of the lens to prevent condensation forming on the front element of the lens. If you are using a zoom lens pointed up into the sky it is possible for the zoom to creep. If you experience this I have used a piece of electrical insulation tape on the zoom collar, (Please don’t use tape which leave a sticky residue when removed) when finished taking the photos remove the tape.
- Tripod – the importance here is that it is stable. In my case I started using a flimsy non branded tripod but found by leaving the legs collapsed it was surprisingly solid
- Black card – you can use this to hold in front of the lens to create some interesting effects
- Black or dark cloth to cover the camera – on a cold crisp night, you will be surprised by the amount of dew which will form on the camera, so to protect the camera placing a cloth (well washed to stop dust) over the camera will protect your camera
- Cable release – this will allow you to trigger the camera via a cable and avoid introducing movement (camera shake) from shutter button.
- Compass to identify North – The whole sky revolves around “Polaris”, the north star, so if you could open the shutter for 12 hours you would find all the stars would scribe half a circle around “Polaris”. If you can recognise the Great Bear, (Ursa Major) and the two stars at the end of what looks like a sauce pan, these stars point towards Polaris
OK, now lets look at taking some photos or star trails:
- Set the tripod on the ground, ideally for stability set at it’s lowest setting – on some tripods they do have a hook so you can hang your camera bag to help give the tripod stability.
- Now we need to set the camera to the following:
- ISO400 – you can go higher, but this does depend on the local light pollution
- Set the camera to manual
- Set the aperture to the widest setting (Lowest F number) – I prefer to click it up one or two steps, but this is something you can fine tune
- Set the shutter speed to 30 seconds or if you have a cable release to the “B” or Bulb setting. The total length of exposure is dependant upon you local conditions (light pollution) but the beauty of digital is it costs nothing to try it.
- Set the auto white balance to daylight – When shooting in Auto White Balance, (AWB) the camera can be easily fooled by the local light pollution
- Set the focus to Manual – cameras find it difficult to focus at infinity at night and uses power hunting around for focus
- In the menu of the Alpha 35, select “Long Exposure Noise Reduction” – this overcomes noise generated when taking a long exposure. So if you take a 30” exposure the camera will take a photo for 30” with the shutter open, then close the shutter and take another 30” with the shutter closed. The camera then subtracts the two images to give a cleaner (reduced back ground noise) photo. It is always worth trying this with and without Long Exposure NR to see the difference. The down side is a 30” exposure takes 1 minute, so you can be stood around waiting for the photo to appear on the screen, (This is why it is important to dress with warm clothes).
- Set your camera to RAW and JPEG – in RAW it is so easy to change the white balance
- Attach the camera to the tripod
- Point the camera at a bright object in the sky and manually focus to infinity
- Now point the camera to the North, at an altitude so you can obtain some foreground interest
- Press the shutter and wait for the 30” to elapse – then another 30” whilst the Long exposure NR does its stuff – Don’t forget if a lot of dew, cover the body of the camera with a suitable cloth for protection
- Review the image on the screen and using the magnifier inspect the image for focus and exposure and adjust as appropriate
I did say you would get to know how to drive your camera
The next steps is to look at being more creative:
- As above, but whilst the shutter is open try highlighting some of the foreground with a torch or flash gun set on a low power. You could even point the low power torch towards the camera and literally paint with light. The main thing with this is keep moving so the camera doesn’t capture you – unless of course that is the effect you wish.
Once you are proficient with this, the next step to a make what is called a Scotch Mount, Haig or barn door tracking platform – just use a search engine for either one of these terms and you will find many examples, which are so simple to make from a few pieces of wood and elementary DIY skills. Once you have made this you can track the stars and then start to track the stars and then capture even more deep sky objects. Then the next steps is to piggy back your camera onto the side of a driven telescope, then you can remove the camera lens and attached the camera body to the rear of a telescope.