Friday, October 8, 2010

Featured Image #2

My next featured image is more recent. I took this in Jasper NP last weekend.

This is an HDR panoramic image taken from the Wilcox Pass trail, looking toward the Athabasca Glacier. On the left is Mount Athabasca (and the secondary peak is Andromeda), and on the right is Mount Kitchener (with the snow-covered peak). The glacier is obvious between them. If you look really carefully, you can see the moon on the right.

An interesting tidbit: the river that comes off the Athabasca Glacier is not the Athabasca River, but the Sunwapta. Likewise, the river than comes down from the Athabasca Pass is not the Athabasca River, but the Whirlpool River. Both are tributaries of the Athabasca, though. The Athabasca River comes off the Columbia Glacier, just a few kilometres from the Athabasca Glacier (both come off the Columbia Icefield). The Columbia River, though, has nothing to do with the Columbia Glacier or the Athabasca River--it heads west to the Pacific, while the Athabasca River flows north to the Arctic. But the source of one or more tributaries of the Columbia River also come off the Columbia Icefield, just a few kilometres away. Additionally, the source of the North Saskatchewan River, which flows east to Hudson's Bay (and on to the Atlantic) also comes off the Columbia Icefield, making it the only place on the continent which drains into three oceans.

Frankly, though, I've always thought the concept of Hudson's bay flowing to the Atlantic is a bit weak. I guess it depends on whether the Arctic Archipelago is in the Arctic Ocean or separates the Arctic and Atlantic Oceans. But if you don't accept that, then you have to have two continental divides, and the one that splits north and east ends up in Ontario. (Actually, even with the traditional Hudson's bay=Atlantic argument, we have two divides, but the north section becomes quite small--just Northern Alberta, a corner of BC, and the Northwest Territories--and we don't worry much about it.)

Anyway, this picture was taken from the Wilcox pass trail which is in Jasper, but just a stone's throw from the Banff border. Actually, some of Banff is in the picture, on the left edge, since the Banff/Jasper border goes up to the peak of Mt. Athabasca. This trail is strenuous but not technically difficult as it goes straight up the side of the mountains. It doesn't switchback,but angles up to the north, quickly getting above the treeline to views like this. Generally, you'd expect to see a group of male bighorn sheep up here, but for some reason this day there were none. One photographer from Montana I ran into on the way up (who was on his way down) said that he'd been coming here at around this time for 26 years, and it was the first time he'd been skunked.

It was shot with a Canon 5D Mk II, and a 28-135 IS lens. That's certainly not my favourite lens, but I wanted to keep the weight down, considering I was also carrying a 300/2.8 IS. If I'd had my 17-40 instead, there'd be a much bigger gap between the two lenses--since getting the 5D2 (my other camera has a 1.6 crop factor) I've missed having a lens between them, so on this trip I dusted off the old 28-135 IS. (It had been sitting on a shelf since I got the 17-40.)

I shot it with several frames, with the camera oriented vertically. Each frame had three exposures. The three exposures were all the same for each frame, so this was done in M mode. Stitching becomes nearly impossible if you use different exposures across a pano. Back at the computer, I ran each set of three exposures through Photomatix to get an .EXR file (which is an HDR format). I didn't tone-map them yet. I took the EXR files into AutoPanoPro to stitch into one larger EXR file. That now went back into Photomatix to tone map. As usual with my HDR work, I tone-mapped it twice, once with the Details Enhancer mode and the other with the Tone Compressor mode. These two images went into CS4 as separate layers. I put the TC layer on top of the DE layer, set the blending mode to overlay and adjusted the opacity to taste. (I think it ended up around 40% in this case.) Then I did the usual levels and curves adjustments. The saved layered 16-bit TIF file is around 2.5 GB in size. Ouch. I really wish someone would figure out a way of losslessly compressing 16-bit TIF files!


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