Astro-Photography – Part II

PART II – The Stars –

In the first part I wrote about photographing the moon and using my DLSR combined with a telescope to effectively capture a pretty decent image of the moon without the need to buy a costly telephoto lens. You could literally spend thousands on a decent lens, as it turns out I sold my telephoto as the only time I got to use it properly was when photographing the moon or on family trips to Dublin Zoo.

So I started thinking about other opportunities to work with just the equipment I already own and also continue with my theme of astro-photography. I have always liked pictures of great big star trails when they contain some foreground interest or plenty of colour but the images that always stood out for me were the kind of image you might see used in time lapse videos showing not only the earth’s rotation but also the amount of stars that can be seen late at night. After doing plenty of research I was itching to get out and try to put what I had read about into practice and more importantly to take advantage of some of the extended capabilities of my DSLR.

At this point I could probably just give you a couple of website links and let you read up about different methods & techniques and then go out and try it for yourself, but where would the fun be in that and I thought I would share my first time experience with you.

So first thing I had to do was scout out a location, I had been on the look out for suitable locations for some time and happened across Lough Tay which sits nestled in a valley along the Sallygap route in Wicklow. I stopped there for a while to capture some sunset shots and as the sun dipped behind the ridge to my right I thought, what a perfect location to photograph the stars above the Lough. Even better if I could get an exposure that could capture the Lough in the foreground as well.

Lough Tay

My plan was very rough and ready, I asked a good friend of mine Stuart to join me and we arranged to meet in the carpark just beside where I took the above shot of Lough Tay. As soon as stepped out of the car I was nearly blown over by high winds. The strong wind was moving the clouds through the sky fast enough that I could catch the occasional glimpse of the stars and immediately I knew this was a great location. The light pollution in the sky was almost non existent. Unfortunately it was not to be on this night, with wind that strong it would have been dangerous to set up on the top ridge of the Lough. It was also extremely cold and very exposed to all the elements.

We decided to head further in land towards Glendalough. The top lake at Glendalough and the area itself is a major Wicklow landmark and has been photographed many times by almost every person I know with a camera. One thing I know about Glendalough is that depending on the direction of the wind up at the top lake, it is probably no better than sitting on the ridge of Lough Tay. Instead we stopped at the St Kevin’s monastic ruins, round tower & graveyard. Located here

Once we had setup tripods, cameras, cable release, remotes, hot drinks & snacks we were all set to try out a few shots.

I had cheated slightly by making a few advanced calculations around exposure times, these were based on the focal length of lens I was packing into my kit bag and the rule of 600.

The rule of 600 is simply this.. you select your desired focal length at which you will take the picture and you divide this by 600. The result will be the maximum amount of time you can leave the shutter open for before the stars start to trail or track. If you want star trails, then you just leave the shutter open for much longer periods.

Example: EF24-70L f2.8 @ 24mm 600/24 = 25 second exposure

The next thing was to get the focus & ISO correct. For the focus, I put the lens on manual focus, then dialled the lens round to the infinity symbol, then back a tiny bit, this is the sweet spot for my own lens. I guess each lens is slightly different but I have heard it mentioned recently that a little bit back from infinity on Canon lenses is about right. For the ISO I set it to the highest available setting on my camera. In my case this is ISO 25600 otherwise known as H2 on the Canon 5D MKII. Now of course using such a high ISO presents a great deal of noise, the main objective however is not to produce a final image but instead to use this as a method to set up and compose your shots but also to see if your images are in focus. It doesn’t matter if your camera does not have ISO settings this high, even ISO 1600 produces images that you can work with and indeed be happy with.

Canon EF24-70L f/2.8 @ 24mm - ISO 25600 - 10 second exposure

As you can see, not a pretty image but it is in focus and more or less where I’m aiming my shots to be. Settings for this image: Canon EF24-70L f/2.8 @ 24mm – ISO 25600 – 10 second exposure

For this next shot I used a lower ISO of 1600. You can really see just how much cloud was around and that the sky is gradually starting to clear from right to left.

Canon EF24-70L f/2.8 @ 24mm - ISO 1600- 30 second exposure

Settings for this shot: Canon EF24-70L f/2.8 @ 24mm – ISO 1600- 30 second exposure

I waited for a little over 10 minutes while the clouds continued to move further away from us. The longer I stared at the night sky, the more stars I could see, truly a breath taking sight when your eyes have fully adjusted to the light. You can also see that there is little to no light pollution from street and building lights. These kind of images are very difficult to make in urban areas.

In this image I let the ISO and exposure time settings work towards bringing out the stars;

Canon EF24-70L f/2.8 @ 24mm - ISO 1600- 25 second exposure

Settings for this shot: Canon EF24-70L f/2.8 @ 24mm – ISO 1600- 25 second exposure, this blew me away and was exactly what I was hoping for.

I then decided to boost the ISO and try to bring more detail into the foreground whilst maintaining the vivid star field that I had already captured.

This is the resulting shot;

Canon EF24-70L f/2.8 @ 24mm - ISO 6400- 25 second exposure

Settings for this image: Canon EF24-70L f/2.8 @ 24mm – ISO 6400- 25 second exposure. You can view all the above images in full size with EXIF information here on PIX.IE

This is not the perfect shot, the stars have even started to trail because really an exposure of about 15 seconds would have been sufficient at this high ISO setting.

What made this image work for me is the sheer amount of detail and an altogether different take on a very popular location. I plan to re-shoot this location in the near future as there are a great deal more variables I would like to try out. The fun as they say is in the learning!

Not a bad set of results for my first night out.

Some things you should consider bringing with you if you intend on doing this kind of photography;

  • The obvious is your camera, lenses, and other gadgets.
  • Fully charged batteries and empty memory cards.
  • Cable release, Remote control or Intervalometer.
  • Good solid tripod.
  • Flash light – Torch.
  • Fully charged mobile phone.
  • Warm clothing and good warm footwear.
  • Hat, scarf, gloves.
  • Flask with hot drink and some light snacks. Bottle or cold drink.
  • Warm blanket, ground matt or folding chair (All of these)
  • Rubbish bag / plastic bag to clean up with afterwards. (Can also be used to put your shoes in if they get mucky)
  • Let someone know where you are planning on going.
  • Last but not least, bring a friend or even a group of friends. It will make the whole experience a lot more fun.

Another shot of the stars that night, but with a less appealing foreground;

Canon EF24-70L f/2.8 @ 24mm - ISO 6400- 25 second exposure

Some good online resources:

http://www.picturecorrect.com/tips/star-trail-photography-tips/

http://danheller.com/star-trails Some great time lapse videos and still images.

http://www.thestartrail.com/ Ben Canales provides a really great first time video tutorial http://vimeo.com/16833554

I hope to organise a photowalk through Photowalk.ie – @photowalkie soon to take some more photos either on a secluded and well sheltered coast line, Glendalough or Lough Tay.

Either way, maybe you will join me 🙂

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