Gav's Blog

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.

I can sympathise with Jeff’s frustration at not being able to get frames for paper sizes from the ISO standard but I think he has it wrong when he suggests that Epson needs to step up and produce US paper sizes. There is a followup, from Scott Kelby’s blog that explains Epson’s position further.

With most of the world actively using ISO paper sizes, it would be far easier for framer producers to recognise that they should start producing frames that support internationally recognised standards, rather than trying to maintain antiquated North American paper sizes. This is just inefficient for international producers, and I’m sure they would love the US and Canada to adopt international standard paper sizes, so that they don’t have to keep producing paper for the North American market. If North Americans want to keep using different paper from the rest of the world, then surely their internal market would pick up on the opportunity?

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From the 300+ features announced in OS X 10.5 (courtesy of SlashGeo), one that I really like the sound of is that Preview will now recognise and make use of georeferenced digital photos – photos that have latitude and longitude incorporated in them.

GPS Metadata Support
Get real information from your photos. If your image has embedded GPS metadata, Preview will show you exactly where that perfect photo was taken. Open the Image inspector and select GPS. Preview pinpoints the location where you took the photo on a world map. From there you can even open the GPS location in Google Maps.

Of course, not many digital cameras support GPS at this point, but there are a number of ways to add lat/long information to photos when post-processing. I recently purchased a very small GPS tracker that I can mount on my camera and it generates a tracklog that can then be matched up with the timestamp in a photo to estimate where the camera was at a given point in time. I am interested in this not only for hobby photography, but also as an application during disasters using this setup for Disaster Impact Assessment and being able to easily produced georeferenced photos of damaged infrastructure for example.