The Winter Tree shot was created using 3 bracketed exposures, shown below. Most DSLRs can be set up to take exposures like this – the camera will take 3 shots (or more depending on the camera) each at different exposures. In this instance they were taken at 0, -2EV and +2EV so that I end up with 3 shots that are all 2 stops apart.
I found the idea of “stops” the most complicated part of getting to grips with photography, but basically a stop is the doubling or halving of the amount of light hitting the sensor – so if we had a 1 second exposure, the next stop down from that would be 1/2s and the next stop up would be 2s. ISO and aperture settings also affect the amount of light hitting the sensor and therefore their adjustment can also be measured in stops, however when taking bracketed exposures these two remain constant – only the shutter speed changes. (A more detailed explanation can be found here – http://www.andystafford.co.uk/exposure-control-stops/)
Having set the camera up to take my 3 shots, I pressed the shutter release and this is what I got…
The numbers underneath each shot are the exposure times – see how the second is 4 times the first, and the third is 1/4 of the first (give or take some rounding). This is due to the 2 stops difference between each shot.
You’ll notice that the shots (apart from the final one) look quite dark. There are three reasons for this:-
- I wanted to keep as much cloud detail as possible so I metered off the brightest part of the sky to make sure I didn’t get any blown highlights.
- It was slightly windy and I didn’t want too much tree movement in the shot so I tried to keep the shutter speeds as fast as possible. (1/30s is still quite slow really considering there was moving foliage but I got lucky in this instance). Photomatix can align movement but better to try to limit the problems at source.
- Accident. I would also have taken a brighter set but I was running out of time.
Once home I loaded the images into Photomatix as follows (Note: if you want to try this there is a link to the source images at the bottom of this article):-
These aren’t the default settings – I find that different combinations of alignment methods work better for different shots. I left Align Source Images set to “By correcting horizontal and vertical shifts” just in case the wind blew the tripod at all and turned off “Attempt to reduce ghosting artifacts”. Movement, especially clouds and running water, can cause problems in Photomatix and I’ll often try different options in these instances.
Once Photomatix had finished its initial processing I pressed the Tone Mapping button and tweaked the settings until I got something that I was happy with.
If you’ve not used Photomatix before don’t be alarmed by how the image looks at the moment – what’s on the screen is only a rough guide. The finished product will look much better :)
The settings that made the major difference to the image were those to do with saturation. With the main Colour Saturation slider set to 0 the image was black & white but changing the Saturation Highlights slider re-introduced colour in the the brighter elements of the shot – the clouds.
If you want to have a go yourself, the source images are available – Source images (3.2MB).
I’m afraid they are jpegs rather than the original raw files, due to space and bandwidth considerations, but they are good enough quality for trying out this example.
Visit http://www.hdrsoftwaretutorial.co.uk/ for tutorials and a discount code which will give you 15% off the purchase of Photomatix.
