Archive for February, 2008
Partial Solar Eclipse on Feb 7 in New Zealand
In New Zealand, we had a partial solar eclipse on the 7th of Feb last week. I was travelling at the time and have only just got back and had a chance to post a shot and tell you how I took it.
NOTE – YOU HAVE TO BE VERY CAREFUL WHEN PHOTOGRAPHING THE SUN! YOU CAN RISK BLINDING YOURSELF!
Details were Canon 20D, 400mm lens, f32, 1/8000, ISO100, Cokin 3 stop ND filter and Cokin ND Grad filter. My basic game plan was to try and reduce the incoming light to the absolute minimum. The purple tinge is due to the combination of filters. The surround is black because I was letting so little light into the lens. It was a sunny day, and this was taken at about 1740 local time in summer.
I shot in manual, with the following techniques used to let as little light in…
1. Set shutter speed to 1/8000 – very little light gets through.
2. Set aperture to f32 – this was the smallest I could get on the lens.
3. ISO100 – use the least light sensitive ISO setting.
4. I stacked the only ND filters I had with me – a 3 stop ND and a grad ND that I aligned so that the darkened band of the filter was over the sun.
What I would do next time? More ND 3 stop filters, or perhaps one filter designed for solar photography. I didn’t think of it until afterwards, but I could have put the 1.4x extender on which would have cut out another stop of light and got me closer to the sun. I’m also not sure if it would have worked, but I would be interested to see if a circular polariser would have cut down the light so that only polarised light was entering the lens.
Safety – I did a number of things to avoid blinding myself…
1. I wore my polarised sunglasses – helped a little taking the edge off the sun.
2. I tried to do as much as possible without looking through the viewfinder.
3. Before looking through the viewfinder, I would hold the back of my hand up to the viewfinder to see how much light was coming through and illuminating the skin on my hand. If it was too bright I would adjust the filter position and check for reduced light intensity on my hand. This was also how I adjusted the position of the camera to get the sun in frame.
4. I never looked directly straight ahead through the viewfinder, rather I kind of looked from the side with a kind of averted vision – just enough to help me focus the camera.
Much of this would have been helped by stacking more filters. A random thought I just had was stacking two circular polarisers, and setting them at different angles so that only a fraction of the light is getting through – this is one technique for observing eclipses – holding polarised sunglass lenses at 90 degrees. Might have to try that sometime.
Even after all that, the sun was still mostly blown out (highlights display in camera) – as you would expect.
Other details…
* Image has not been post processed.
* Image here has been cropped to a square frame – I didn’t have any opportunities where I was to try and include a silhouette in front of the sun (I was on the west coast of New Zealand and there is nothing but ocean there). Hence focus for me was not on composition as much – but more about the technical aspects required to photograph an eclipse.