Sunday, May 07, 2006

Birch pollen corona

A couple of days ago birch started flowering in Southern Finland and pollen coronae appeared in the sky. I photographed this corona yesterday and here is a composite of six individual images taken in one F-stop intervals and merged together with the HDRI-technique. The photo was enhanced rather heavily by applying unsharp mask and hue adjustment.

More natural version of the same photo is here. Another HDR-image of birch pollen corona, taken by Timo Kuhmonen, is here. See also the pollen corona around the moon by Jari Luomanen.

3 comments:

Les Cowley said...

Marko - Can you tell us more about the HDRI technique that you used? I.e. How did you merge the six images to preserve the full tonal range? What software?

Nice one!
Les

Marko Riikonen said...

I used photoshop CS2 which has HDRI-tool. Original photos were 12-bit NEF from Nikon D70. I saved the HDRI as 32-bit and applied some unsharp mask. Then I changed it to 16-bit and applied hue and levels (they don't work in 32-bit mode).

The tonal range has indeed suffered along the process because I wanted to make to corona stand out as well as possible.

Here is the same corona photographed with different lens and less treatment and compared with one of the single photos. At the time these images were born in my computer the sun was still shining and I was able to make comparison with the real thing. The corona in the sky looked pretty much like the HDRI-image.

Les Cowley said...

Thanks Marko for the explanation - a powerful technique.