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Archive for September, 2012

Recently, I’ve seen a National Geographic Magazine documentary about the selection and making of their best ten 2011 photographs. You can see all ten photographs at:  Top Ten 2011 NGM Photos

I liked best the spirit bear story and the photo of the white bear laying contently in the moss-draped green rain forest. If you ignore the bloody salmon between his paws, the bear looks almost angelic in that setting. However, the report of the photographer coming to the close proximity of the bear is the really dangerous stuff. According to Chris Johns, Editor in Chief at NGM:

“Paul Nicklen, the photographer is a master at getting closer. He gets close enough to take this beautiful forest with this beautiful bear, eating a salmon, and make it all come together in a photograph that captures your imagination. I feel like I’m there. I can almost smell that forest, the bear. This is Paul’s home. This looks like a photo he took in his backyard of a dear friend.”

To see the whole series of the spirit bear photographs, click on the following link White Spirit Bear Photos

Western Canada is the only place in the world that’s home to this unusual form of black bear, whose fur is white due to a genetic abnormality (it’s not an albino). The white spirit bear is also called kermode, and with total population of about 200, it is a more rare species than the panda bear.

Paul Nicklen reports that he spent two months looking for the bear, when “this incredible big white male came right beside me about three feet away, he grabbed a fish and ate it. I then spent my entire day living my childhood dream – walking through the forest with this bear. I actually got to sleep within three feet of him and photograph him. It was a truly amazing experience.”

I have to confess that about twelve years ago in northern Ontario, I came close enough to a large black bear to feed him an apple. Right between his teeth.  OK, it was a captive bear in a large fenced-in enclosure, and I went in with a warden, but if we had ran out of apples, that bruin could have made a winter food cache of both of us. Mellow fellow, but really big, and drooling too much for my taste. All this white foam coming out of the black mouth from the shooter’s perspective was just too contrasty, and trust me, not a pretty picture. It seems that Pavlov’s conditioning experiment works also on bears – he definitely associated our visit with food.

I’m glad for Paul that he was able to fulfill his childhood dream and walk all day through the forest with the bear, but reports like this may entice some well-meaning hikers to approach wild black or grizzly bears, and these encounters often end tragically. As reported in my previous post, just last month in Alaska, a large grizzly bear killed and partially devoured an experienced hiker who got too close to the bear.

Hiker, killed by a grizzly

Now, it could well be, that the bears on a salmon diet are much calmer and of a better disposition than the grizzlies grazing on Denali tundra or starved black bears during a dry summer in Algonquin Park. I can attest that after eating a smoked or grilled Pacific salmon I feel also at peace with the world around me.

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A grizzly sprinting at 35 miles an hour from hundred feet away will sink its teeth into your expedition cargo pants in less than two seconds, giving you just enough time to engage the autofocus, select burst mode, and press the shutter. Depending on your reaction time and camera model, your closed ones may inherit six to ten pre-mortal frames that could be made into a very short viral video clip.

Reaction times for trained athletes vary from superfast 40 ms for Muhammad Ali’s fastest punches to 150 ms required to return a table tennis ball. Sprinters take 100-150 ms after registering the starting pistol to jump off the blocks.

As an action photographer, you might find it interesting that once an image hits the retina, it takes approximately 100 milliseconds before it consciously registers in the brain. Although the light travels much faster than sound, the human’s body visual system is actually slower than our audio system. When the light or an image hits our retina, the photons must be translated into a chemical signal that in turn must be converted into an electrical impulse that can be carried via the nerve fibres to visual cortex residing in the back portion of the brain. Visual cortex will process the input signal and split it into two entities – one processing the shape and identity of the object(s) we see, and the other decoding the location and motion of the object(s). These two streams are then combined into a final information block which is converted into conscious awareness. Lot of complex data manipulation and processing.

Neuroscientists have discovered another problem with the real-time watching. A simple assumption is that our visual system continuously monitors the surroundings and records it in “video camera” style. In reality, we are continuously scanning the entire scene and taking a quick sample from each location. The seamless connection and stitching of the entire scene is handled by the brain that combines the individual segments into an equivalent wide-screen scene that appears like a movie.

Typically, we perform about five such visual relocations per second with the minimum time of 200 milliseconds to shift our viewpoint. Then you add 300-400 milliseconds required to execute a cognitive decision and another 50 milliseconds to engage a motor command to be communicated by nerves to the finger on the shutter. All these activities add up to 500-600 milliseconds or half a second, which translates to several missed frames.

Case in point:

This past summer, I was photographing a whitewater kayak race. I used a 70-300mm zoom lens across its entire range, shooting at F8 in single frame mode. From my vantage point, I was able to follow the racers, set the continuous autofocus, and fire off one or multiple shots in each gate. Except one tricky spot on the river with a fast short drop followed by a haystack. I took a number of shots in that spot, some better than others. When I examined images on my computer screen, I came across the following shot:

I like this image, and it was a sheer luck capturing it. Surely, I wasn’t composing and focusing for the hand with paddle. Most likely, I noticed the racer just coming down the chute, focused on him and pressed the shutter. Let’s assume that in that particular drop the water moves at 15mph (24km/h), kayak moves relatively to the water at 5 mph (8km/h), so the resulting speed is 20mph (33km/h). If the distance from the top of the drop to the bottom is 5 ft (1.5m), moving at that speed, the kayak can cover 9m in a second, or 5 ft (1.5m) in 165 ms. This corresponds roughly with 100 ms required for a transmission of the image from the retina to the visual cortex, plus another 50 ms to press the shutter. And that explains the confluence of kayak being in the hole just with the hand and paddle visible behind the standing wave and click of the shutter in that very fortunate moment.

As the kayaker cleared the haystack, he was slowed down sufficiently, that I could easily focus on him in that position and make another exposure. If his speed in that moment was around 3-4 mph, he would cover in 165 ms only 1 ft (30cm) which didn’t pose any problem for locking the focus or sufficient depth of field at that distance.


 

Back to the grizzlies:

On August 24th, 2012, in Denali National Park, a grizzly attacked and killed a lone backpacker who was photographing the bear from just over 40 yards away. He took 26 pictures of the bear with his camera over a span of 7 1/2 minutes, but the bear seemed to take notice of him only for the last few seconds, according to National Park Service officials who based their assessment on satellite imagery and photo time stamps. The park service said that, based on “initial evidence,” authorities believe a bear attacked the backpacker by the river and dragged his body to a “food cache site” in a bushy area 100 to 150 yards from where the attack occurred.



Picture above taken by yours truly a few years ago in Denali from a safe distance, not too far away from the fatal site.

 

The hiker took the first bear shots with a wide angle. Then he zoomed in. The last five pictures, taken in a span of 13 seconds, show the bear lifting its head up, looking away from the camera, and then turning towards the photographer (did the hiker sneeze or yell at him?). The mauling probably occurred almost immediately after the last image.

“A bear could cover that distance before a person could react,” said the park ranger. The bear was estimated at 600 lbs (270 kg), big for Denali. It was a mature boar, at least 5 years old.

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Few months ago, we compared three Nikon 50mm lenses and examined center and corner sharpness. To complete the exercise, this time, we’ll compare three Canon lenses – Canon 50mm/1.4, Canon 50mm/2.5 macro, and a 17-50mm Tamron zoom XR DiII SP. The Tamron zoom is better and faster than the Canon 18-55mm kit zoom that was omitted from the comparison. For my type of shooting, I find also, that the 17-50mm range is more useful than 18-55mm.

All images were obtained on a bright, sunny day, at F8, and 1/1600s, and a APS-C format Canon T2i camera was mounted on a solid tripod. The images were not manipulated nor sharpened.

The first set of images shows the overall uncropped images (reduced to 720×480 size).

1. Canon 50mm/1.4 – ISO 200, F8.0, 1/1600s

2. Canon 50mm/2.5 – ISO 200, F8.0, 1/1600s

3. Tamron 17-50mm – ISO 200, F8.0, 1/1600s

The primes show better contrast and more vibrant colours than the zoom lens (notice the red chimneys and the reflection in the water). On the other hand, Tamron lets more light through at the same aperture. If you are going to print it in small size or use it just for Web, you won’t notice any difference in image quality, regardless of the lens used.

 

Next set of images shows a crop of the middle section (you can click on the images and see it in full 100% size).

1. Canon 50mm/1.4 – ISO 200, F8.0, 1/1600s

2. Canon 50mm/2.5 – ISO 200, F8.0, 1/1600s

3. Tamron 17-50mm – ISO 200, F8.0, 1/1600s

Both Canon primes are very sharp in the middle section (remember, this is output from a RAW, unsharpened image). As expected, the zoom lens is not quite as sharp, but again, printed at small to medium size or reduced to a web size, it is quite acceptable (you’ll need to view the samples at 100% to see the difference).

 

The last set of images shows the leftmost section in 100% crop

1. Canon 50mm/1.4 – ISO 200, F8.0, 1/1600s

2. Canon 50mm/2.5 – ISO 200, F8.0, 1/1600s

3. Tamron 17-50mm – ISO 200, F8.0, 1/1600s

Both Canon primes show excellent corner sharpness and some moire on the metal netting of the deck balcony. The 50mm/2.5 macro shows slight amount of green fringing along the vertical edges (noticeable on the two white beams under the roof), but that can be easily corrected in Lightroom). The Tamron zoom, as expected, is not quite as sharp, but due to the loss of knife-edge sharpness, it indirectly gets rid of the fringing, and moire on the balcony is also less pronounced.

Conclusion:
If you need the best quality, the 50mm/2.5 macro is hard to beat (it is also the least expensive of three tested lenses). In image quality almost indistinguishable from 50mm/1.4, and you get also the macro capability. Of course, if you need a fast lens in low-light situation or better isolation of the main subject, the 1.4 aperture will be the better choice. Tamron zoom is the longest and heaviest of the three, and not quite as sharp as the 50mm primes, but in good light and exposed at its sweet spot, it delivers good image quality and a useful range of focal lengths.

One more difference:

If you look carefully at the rightmost window in the cropped version in the last set of pictures, you’ll notice a startling difference. In the first two images, photographed with Canon prime lenses, the test subject sits straight and appears interested in his surroundings, whereas in the last photo he stopped cooperating and fell asleep.

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