©2000-2016 BTLeventhal.com / Bruce & Tamy Leventhal. All rights reserved. No image on this site may be used without permission.
The evolutionary origins of seals, sea lions and walruses is still unsettled science. Historical taxonomic studies suggest two potential lines of ancestry which include the Ursids (bears) and the Mustelids (otters, minks, ferrets…). While molecular and fossil evidence now appear to implicate an otter-like ancestor, some continue to cling to the “bear hypothesis.”
Collectively belonging to the Clade Pinnipedia, pinnipeds are carnivorous, fin-footed semiaquatic mammals. With the exception of the Baikal seal (Pusa sibrica), pinnipeds are marine mammals divided into three distinct groups. The Otariidae or true eared seals, possess ear flaps and a flexible hind flipper that allows for semi-coordinated movement on land. Familiar examples include the California sea lion, Zalophus californianus, who’s tendency to bark and play make them a favorite of zoos and marine parks. While significantly larger than sea lions, the Odobenidae have a similar body morphology, but are distinguished by their enormous hairless bodies and pronounced tusk-like canines. Commonly known as walruses, only one extant species remains. Sadly, their long-term viability is now threatened by the rapidly changing arctic climate. The significantly smaller Phocids, lack external ear flaps and have inflexible hind fins. Far more cumbersome on land than their sea lion brethren, “true-seals” are more aqua dynamic with their stubby clawed forelimbs and torpedo-like body.
All Images were Made with a Nikon D7200 and Nikon 200-400mm f4.0 VR1 Lens
©2000-2015 BTLeventhal.com / Bruce & Tamy Leventhal. All rights reserved. No image on this site may be used without permission.
Earlier today a group of last year's graduates showed up in my classroom to discuss the start of their college careers. All three are now biology majors at the same institution, and I couldn't help but feel a bit of nostalgia for the life I once lived. I wanted to wax poetic and share stories from my glory days, but chose instead to internalize my exploits as I probed for information about college life in the modern era. Now 32 years removed from my own freshman year, I can't help but wonder how I got to where I am today. First a researcher and now a public school educator, at age 50 it's hard not to think about the many missed opportunities and false starts.
There was a time when I dreamed of pursuing an academic career in field ecology, and while I played the role in college and graduate school, I discovered that the world of deep academia was not for me. Alternatively, I could also see myself working in the field behind a camera and lens. In the 1980's nature photography was a specialized discipline; it was a meld of science, photographic arts and business. However, it didn't take long for me to realize that I lacked the skill, patience and risk tolerance required to be an entrepreneur, I feared that a career in photography was as unlikely as one at a university.
In the end, teaching found me rather than the other way around. The career was a safe choice at the time, and was intended it to be a stop-gap until I "figured it out," or sequestered the dollars needed to ride out a PhD program. Twenty-three years later, this accidental teacher has embraced the mentor role and has found pleasure in an unexpected vocation where every day is different and peoples' lives are impacted. There is no doubt that I still dream about the past and wonder what the present could have been, but this life is one that I live with no regrets.
Frequent visitors to this blog know that I rarely review camera gear. In fact, most of the 500-plus posts on my site fall into one of two general categories… the process of seeing or the biology of what is seen. While I’m not known for reviews, there are times when I feel compelled to share my thoughts about a piece of photographic equipment. Prompted by the dearth of field reports on the Nikon D7200, the following might be useful to those contemplating its purchase.
For the sake of some background, readers need to know that I am a fairly recent convert to Nikon DSLR’s. Having been a shooter since the film era, most of my digital work has been with Canon cameras. In September 2014, I had the opportunity to acquire a Nikon 200-400mm f4.0 VR at an incredible price, and used this as justification for switching brands. Prior to moving to Nikon, my primary wildlife kit included a Canon 1D MkIII or Canon 7D paired with a Canon 300mm f2.8L IS and converters. The combination of this gear served me well throughout the United States, Canada, Central America and Africa. My decision to change systems was solely based on a desire to work without tele-converters and gain the flexibility that a high-end “super-tele zoom” could offer.
The transition from Canon to Nikon for landscape work was surprisingly smooth. Trading a Canon 5D MkIII for a Nikon D800E was a win, as the Nikon has more resolution and a wider dynamic range. Having spent most of the equity in my Canon gear on lenses and the D800E, relatively little was left for the purchase of a high-end wildlife camera. For the better part of eight months, my wildlife photography was done with a pair of 12MP D300’s. Revolutionary at the time of its introduction in 2007, the D300 now seems somewhat primitive with respect to modern DSLR’s. Although the build and frame rate of the D300 and D300s make these cameras relevant in 2015, the relatively shallow dynamic range, low sensor resolution and high ISO noise are sources of angst for wildlife photographers seeking a Nikon DX (crop) camera option. In May 2015, I decided to give up the rugged build and fast frame rate of my D300’s in favor of a smaller and less robust “prosumer” camera.
Enter the Nikon D7200 - The Good
Rather than a review, mine is a wildlife photographer’s reflection on the D7200’s strengths and weaknesses when pursuing active subjects. If you are interested in a list of specifications, new features and the function of buttons, I suggest you follow one of these links: review by dpreview or review by Thom Hogan.
In mid May I traded two D300’s towards Nikon’s latest DX offering with an equal mix of pro and consumer features. Designed around a Sony 24mp sensor, I knew that the dynamic range and relatively low high-ISO noise of the D7200 would best my prior Nikon wildlife cameras. The need to move and bin 24mp files was a serious problem for Nikon’s prior model (D7100), which famously had a very shallow buffer. Now that I’ve use my D7200 to photograph flying birds, aquatic mammals and rainforest wildlife, I can safely say that the D7200’s buffer is capable of holding and moving files rapidly enough to photograph active subjects. In nearly three months of fairly heavy shooting, I have only hit the buffer limit on two occasions. By relying on high speed and modern SD cards, the D7200 matches the processing speed of my prior D300 bodies.
The autofocus performance and accuracy is a definite upgrade from the Nikon D300. Like the D300 and other professional Nikon bodies, there are 51 AF points that stretch across most of the viewfinder. With so many autofocus points, I have little difficulty placing an AF target on the spot that meets my compositional goals. The AF system is fast and accurate, especially when set to Autofocus Continuous Single-point mode (AFC-S). For moving subjects like flying birds or running animals, I will I set the camera to AFC-S, and use the joystick on the back of the body to follow my subject. Whenever I am faced with an erratically moving animal like the elegant tern pictured below, I’ll migrate from AFC-S to AFC-9. By doing this, the autofocus system uses nine autofocus points in a 3x3 grid to maintain critical focus. While this sounds useful in theory, I rarely shoot in expanded AF mode because the focusing speed slows and critical focus is easily lost. In expanded AFC-mode, the user selects a specific target with one AF point, and the surrounding eight points assist to maintain focus. If the chosen point drops off, one the surrounding eight points re-establishes focus on the subject. Unfortunately, those surrounding points might lock onto a wingtip, beak or whisker rather than the eye that was originally selected. It is not until you begin your edits on a computer will you realize that most of your images are not as sharp as you expected. Admittedly, the deliberate decision to rely on a single AF bracket results in some missed opportunities, however my in-focus rate increases dramatically by shooting in this more conservative and less automated manner. To summarize, when shooting in AFC-S (single point continuous autofocus) mode, the camera readily locks onto a moving target and maintains focus at the cameras maximum frame rate as long as the autofocus bracket is accurately placed on the intended target.
The sensor in the D7200 has exceeded my expectations for resolution, noise control and dynamic range. When compared to the D300, the seven-plus years of technological improvements are quite clear. The D7200 produces detailed pictures due of its 24 megapixels packed into a 1.5 times (DX) cropped area. The result of this high-resolution cropped sensor is many more pixels per feather than the D300. These resolution gains allow for flexible cropping and greater compositional control. Comparing this sensor to the one in the D300 seems unfair. Both the dynamic range and relatively noise-free images allow me to comfortably shoot between ISO 100 and 800 without substantially degrading the image. Usable at ISO’s of 1600 to 3200, the D7200 produces high ISO photographs that clean up nicely with just a bit of noise control. The latter is in stark contrast to the D300, where I find that any image shot beyond ISO 400 was unacceptable due to noise which causes the image to degrade substantially. When compared to the Canon 7D’s that I once used, the key difference is the absence of pattern noise. The 7D always had difficulties with blue skies, blacks and fog. When photographing animals against a reduced color palate, bands of noise and unnatural splotches were common artifacts in my files. The Nikon D7200 has far better noise control at high and low iso than did my Canon body, all of which allows for more flexible shooting, as well as processing in underexposed regions of an image. To me, the sensor improvements alone are enough to justify my purchase of this camera.
The Nikon D7200 - The Bad
All is not ice-cream and candy with the D7200. In many ways, the camera is a placebo for what many Nikon wildlife photographers want… a D400. As it stands, given the opportunity, there would be a small army of us who would gladly adopt a Canon 7D MkII if it were made with a Nikon mount. Where the 7D MkII is a clear replacement for the original 7D, the same cannot be said for the Nikon D7200 when compared to the D300. Ad a wildlife photographer, there are two downgrades in the D7200 that directly impact me in the field. The D300 has a robust weather sealed body that follows the design ethos of Nikon’s professional cameras. Picking up the D300 feels good in the hands and its mass balances nicely when mounted to a high-end telephoto lenses. Changing ISO, white-balance and shooting modes on the D300 is essentially the same as on my D800E. In contrast, I often find myself fumbling or looking through menus to make these same basic changes on the D7200. Furthermore, the D7200 feels light in the hand, lacks a deep grip and does not balance well on my ball head or gimbal when mounted to the 200-400mm f4.0 VR. While I do not have the confidence that the D7200 can withstand the abuse of a D300, I do know that it performed well in the humid and often heavy rains of Costa Rica. At one point, I was stuck in a downpour and did not cover the camera or lens adequately. As the rain pounded on the body, I did what I could to shield vulnerable spots. The D7200 survived the experience and was ready to use in spite of the rain. So, while it might not be as weather tight as a D300, so far, the camera’s weather seals appear to be adequate.
My second key concern with the D7200 is related to its frame rate. The camera has the ability to shoot five 14-bit images per second (5 fps) or six 12-bit images per second (6 fps). When compared to the D300s, my current body body has a slower frame rate. Using the D300s with an MB-D12 grip and the high performance/high capacity EN-EL4(a) battery, this 6 year-old camera still manages to shoot eight 12-bit images per second (8fps). This difference in frame rate can be substantial if you are hoping to photograph the nuances of a subject. A burst of 8fps creates the opportunity to catch a bird landing on its nest with the feathers displayed just right, or a brief expression that might be otherwise lost when the frame rate is slower.
The Nikon D7200 - The Ugly
There is not much “ugliness” to the D7200, however there is a characteristic in the autofocus system that is a source of great frustration. To be clear, I am not sure that Nikon produces a camera that would resolve my issue, but after 25+ years of autofocus technology, the solution should not be unobtainable. Specifically, I find that the D7200 and other Nikon bodies have a high AF-failure rate when photographing low-contrast subjects. Because most wildlife is active at dawn and dusk, low-contrast conditions is much of what I see. When trying to lock onto a dark eye against relative dark fur, as in the beaver pictured below, the autofocus failure rate is very high. In fact, a careful look at my files will reveal that less than one-half of the images meet my sharpness criteria. The inability to lock-on or maintain critical focus of moving subjects under these conditions just drives me crazy!
The Nikon D7200 - The Bottom Line
As I survey the landscape of Nikon cameras that could meet my needs, most fall short in one way or another. I am a “simple kit” guy with a fairly limited budget. Buying the Nikon 200-400mm f4.0 VR was a stretch for me. With a maximum aperture of f4.0 and focal length of 400mm, this lens is the most affordable long fast glass available for the Nikon system. The Nikon 500mm and 600mm lenses are out of budget, while the Tamron or Sigma 150-600mm f5-6.3 lenses are too slow for my needs when extended to 400mm and beyond. My solution to these limitations is the use of a high resolution crop sensor camera. As a result, the faster full-framed Nikon D700, D3, D3s, D4 and D750 are unsuitable bodies that would require extensive cropping to meet my compositional goals. Because of these limitations and the lack of a modern high-end crop body (like the mythical D400), the Nikon D7200 provides the image quality that I am seeking with just enough speed to meet my wildlife photograph objectives.
©2000-2015 BTLeventhal.com / Bruce & Tamy Leventhal. All rights reserved. No image on this site may be used without permission.
In biology, energy is king. Solar energy is at the core of nearly every ecosystem on the planet, and this energy from the sun drives everything from the complexity of a food web to the cellular processes that replicate the genetic code passed from one generation to the next. Deprived of the energy required to do work, the essence of an organism, its “livingness,” comes to an end.
In living systems, energy is only half of the story. For life to exist, molecular vessels (organisms) must be modified, organized and assembled in ways that can harness the energy. These pliable molecules are commonly referred as biological nutrients.
A fundamental concept to all biological systems requires that energy flows while nutrients are cycled. Energetics are subject to the physical laws of nature, and life can only exist if it obeys these laws. The ”first law of thermodynamics” informs us about energy’s limits. Energy in a biological system is conserved but not recycled. This energy is transferred and transformed from molecules to motion, from motion to molecules, but can not be created nor destroyed. The energy trapped by the molecules in our food is transferred to packets of chemical energy that drive our cellular processes. Simultaneously, some of the energy from each meal results in the generation of heat, or the vibration of molecules, that will increase the entropy in a living system. This energy is not lost, it just flows from one state to another.
In contrast to the energy on the planet, nutrients are limited and must be recycled. Without the cycling of carbon, oxygen and nitrogen the resources required to build an organism will diminish. One of the great harmonies of living systems is the ability to harness energy to order molecules in a manner that can sustain itself for a finite period of time. However, as this molecular order is subject to the stresses of the environment, an ecosystem and time, it becomes less efficient and less capable of harnessing the energy required to remain whole. It is at this point that death ends the cycle inherent in every life. To this biologist, death is nothing more than the completion of a life that includes the wonderful serendipity of unique molecular interactions on this planet we call Earth.
It's not the "Last Call," but it is getting pretty close. My Visualizing Landscapes workshop is filling fast, but four spots remain. If you're interested in learning the basic techniques for making compelling compositions in nature, learn / review exposure theory and practice techniques in the field join me in the afternoon on July 17 and morning of July 18. Lecture and discussion sessions will occur in the WestPhoto Classroom in Minneapolis to be followed by a morning shoot near Stillwater, MN. Check out the --> FLYER <--
Hope to see you on the 17th.
Historically and architecturally a keystone is the trapezoidal block at the peak of an arch that maintains the stability and integrity of its structure. Remove the keystone and the arch collapses.
In ecology, we often speak of keystone species when discussing extinctions or ecosystems in peril. Much like the keystone of an arch, any given species might be the keystone within a web of trophic interactions. For example, consider the humble sea otter (Enhydra lutris). This cuddly mustelid of the sea is much more than just eye-candy. In the late 1970's the sea otter population was relatively large and the kelp bed "forests" of the Pacific were expansive. Overfishing depleted the seas of fish, and seal populations began to wane. Interestingly, orca whales were forced to switch from feeding on seals to consuming the healthy otter stock. As the otter population collapsed, the sea urchin population spiked. The expanding urchin populations decimated the kelp beds and thus the resident the fish nurseries. The depleted fisheries now lost the opportunity to recover from years of overfishing.
So, who's the keystone in this story? It turns out that otters eat sea urchin when the urchin population hit a critical mass. In the absence of the otters, the prolific urchin population exploded, and the kelp-bed ecosystem collapsed.
The image pictured was taken in the Elkhorn Slough near Monterey, CA. Fortunately, the sea otter is now protected species by the Marine Mammal Protection Act. As a result, the California coastal ecosystem is recovering because of the important role this species plays within its ecosystem.
The tallest trees in the world produce some of the smallest cones. Coastal redwoods grow to 110 m (360 ft) and have a trunk diameter of 9 m (30 ft) near the base. Not just giants, these trees are among the oldest organisms on the planet. Ring counts suggest that some California redwoods (Sequoia sempervirens) can live for more than 1800 years. Found from California’s central Pacific coast to southwestern Oregon, these relics of the ice age have very tiny cones. The egg shaped cone has spiraling scales, is 3 cm long and only weighs a few grams. In contrast to redwoods, coulter pines (Pinus coulteri) along the coastal mountains of Southern California, grow to only 24 m (80 ft) in height and produce the largest cones. The spiky coulter cone is 20 to 40 cm (8 to 16 in) long; more than ten times the length of the largest redwood cone. Furthermore, this beast of a pinecone weighs as much as 5 kg (10 lb).
Laozi, author of Tao Te Ching, lived around the the 6th century BC and is considered to be the “father of Taoism.” Often associated symbolically with a black and white circle that melts together to form the yin and the yang, Taoism is a philosophy and ethic that suggests we live in the moment and go with the flow. When considering the nature of one’s existence, Laozi (also Lao Tzu) saw water as a metaphor for being. His thoughts on this subject continue to resonate today, “The very softest thing of all can ride like a galloping horse through the hardest of things. Like water, like water penetrating rock, and so the invisible enters in.”
Tao Te Ching
First, let’s be clear on this one… everything that follows is a rough estimate, yet oh so intriguing. If you’re like me, and might I add… I hope you’re not, you once wondered how many grains of sand were on that beach where you built that first sand castle. I was one of those “how many?” type of kids and also pondered how many plants and stars there were as well. It turns out there is a study completed that compared the amount of sand on Earth to the number of stars in the “visible” universe. If we include all of the sand on the planet’s beaches and deserts, a rough estimate suggests that there are 7.5 x 1018 grains of sand on the planet… that’s 7,500,000,000,000,000,000 or “seven quintillion, five hundred quadrillion” units of sand.
While we know there is a lot of space to space, and there are many more stars than those we can see on a clear night, it turns out that the number of stars truly dwarfs the grains of sand on our humble little planet. Using what is visible with the Hubble telescope and our best predictions of the volume of the universe, University of Hawaii researchers estimate that there are 70 thousand million, million, million stars in the observable universe (70,000,000,000,000,000,000) which works out to be about 9 stars for every grain of sand on the planet. What I found most striking about my research on this topic is that the number of stars in “the heavens” is nearly equal to the number of water molecules in ten drops of water!
Blatner, David. Spectrums. London: Bloomsbury, 2012. Print.
Krulwich, Robert. "Which Is Greater, The Number Of Sand Grains On Earth Or Stars In The Sky?" NPR. NPR, 17 Sept. 2012. Web. 25 Jan. 2015.