Wednesday, 25 April 2007

Sony Alpha 100 panoramas

Since I didn't have free time lately, I could not play too much with my new camera. I wanted to understand how easy it could be to create a panorama from over 20 pictures without spending too much time on it.

What I did was to mount the 75-300mm on the Sony Alpha, putting it in a backpack with a tripod and the go on the top of an hill.

After mounting the camera on the tripod, I leveled it, and then I've taken two set of pictures, the first zooming at 75mm (full back), the second at 300mm (full forward).
The first set consisted in 23 pictures saved at 10 mega pixel with maximum quality, while the second in 44 pictures. I should have taken more pictures, but sadly enough I had all the memory cards almost full, and so I couldn't do it.

For the stitching I've used Hugin, a free GUI interface to Panorama Tools. Through these open source projects, I was able to create two huge images, the first was 19104x1791 pixels, while the second 19267x1829. The computed images are not at the maximum possible resolution because Hugin said that 2 Gigabyte of RAM was not enough.

Since it's not very practical to show such images on a browser, I had to used another tool, called Zoomify, that even if it's not an open source project, was at least available in demo mode:

Here there the results: (full size link) (full size link)

What did I learn from this experience? Quite a lot actually:
  • In the computed images, it's still possible to identify how the pictures where stitched together, and this is because, even if Hugin/Panorama Tools are quite good in matching image tonality and exposure, next time I will use the AE Lock function on the camera, so that each set of picture is taken with the same aperture and exposition (is white balancing locked too?)
  • 2 Gigabyte of RAM are not enough when it comes to generate images bigger than the ones displayed here, but maybe tweaking some parameters will lead to minor memory usage
  • Shooting trees and grass without a polarizing filter leads to poor image quality, this is why I've already ordered a cheap 55mm circ-polarizing filter on eBay
  • I will never go out for a shooting trip with full memory cards again,
    I will never go out for a shooting trip with full memory cards again,
    I will never go out for a shooting trip with full memory cards again....

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