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Depth of field with long lenses and two subjects

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Song sparrow, Juvenile white-crowned sparrow, and adult white-crowned sparrows at Munson Pond. Many times when photographing birds, I will find more than one in my viewfinder.  A single bird is always relatively easy to shoot - focus on the bird (head if possible) and press the shutter button.  But what do you do when there is more than one bird? You basically have three choices.  You can focus on the closest bird, focus on the farthest bird, or focus on a point somewhere in between.  The best choice will vary a lot depending on the exact situation, but there is, I believe, a good general first choice. The best, general first choice is to focus on the closest individual.  The reasons are as follows.   the front individual will be larger and therefore have more detail than the individual(s) behind it. depth of field is so limited (I used a 500 mm with a 1.4x TC on an APS-C camera to give me a relative focal length of around 1000 mm) when shooting wide o...
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The moon is important life. Really.

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Low tide near Birch Bay, Washington, 2013 It turns out that the moon is important to life.  The obvious assist is with tides.  The moon exerts a pull on the Earth.  This pull, due to gravity, causes the movement of water on the oceans, to such an extent that tides on the Bay of Funday have a range of more than 50 feet.  That's 100 billion tons of water, twice every day, up and down a 150 mile channel.  Regular tides are far less than that of course, but the idea here is that the moon moves a lot of water. High tide brings important nutrients and debris inland.  It also removes shoreline features through erosion which facilitates nutrient distribution and the rock cycle.  Low tide allows a great many organisms to feed on intertidal species.  The whole marine food web is greatly enhanced by tides. Then there is the fact that the moon stabilizes the Earth to some extent.  The moon's gravity holds the Earth's tilt in its current plane of rotation...
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Cool things you didn't know - 5 - breathing using a plant for air: Plateumaris

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I believe this is an adult reed beetle - genus Plateumaris - on a yellow iris flower. Have you ever heard of an insect breathing underwater by using the air inside aquatic plants?  I have heard of it, but never researched it until now. Reed beetles, like the one above, have two distinctive habitats.  As larvae, the insect attaches to underwater plant parts such as the yellow iris in the photo.  They feed on the roots and stems of the host plant, but the peculiar thing is that they get their oxygen from the plant itself.  They tap into the  aerenchyma (air-filled tissue) of the plant using two spine-like hooks located on the abdomen.  This allows gas exchange to occur with the insects' breathing apparatus (malpighian tubules).  You can see the two spine-like hooks in the image below (lower left image).  Taken from  this source . Have a look at lower left image - reed beetle grub showing the breathing hooks. The adults live above water and look...
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The Colorado River - Endangered?

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The Colorado River in the American Southwest The Colorado River is heavily dammed.  There are 7 major dams that produce reservoirs along its 1450 miles.  Along its tributaries, there are another 50 or so.  The largest of these include Parker Dam, Hoover Dam, Glen Canyon Dam, and Grand Valley Diversion Dam.  These store not only vast amounts of water, but they are also important for hydroelectricity and as a source of fresh water. It is the demand for fresh water that is causing the problem.  Irrigation, water for industry and public consumption, and evaporation all contribute to its depletion.  The river system supports some 40 million Americans and irrigates over 5 million acres of farmland.  Much of California, Nevada, and Arizona get their water from the Colorado River. The river basin provides water for about 10 percent of all the United States. Between the dams, water extraction, and reduced rainfall from global warming, the river is running dry i...
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Cool things you didn't know - 4 - The Jerusalem cricket

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Jerusalem (sand) cricket I photographed in 2008 with my Nikon D70 and macro equipment. Neither from Jerusalem nor a cricket, this is a strange insect.  It turns out that there may be anywhere from 20 - 100 species of this unusual nocturnal forager.  Scientists aren't sure about the number because of the relatively small area each population lives in.  Genetic variation may show a high degree of overlap between groups, making species identification somewhat challenging. Being wingless and fossorial, they don't travel far from their burrows, only going out when it is dark to feed.  Although they are somewhat docile, they have a strong bite and can inflict an injury on anyone mishandling one.  They use that bite to capture other insects or to eat plant matter, or scavenge.   They dig their own burrows.  Their strong legs, strong jaws, and bulbous head all allow earthen material to be excavated and then moved to create a hollow.  These relatives ...
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Cool things you didn't know - 3 - Temperatures affect dragonfly wings

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Whitetail dragonflies.  Center:  female.  Corners:  male.  (right one isn't my photo). Whitetail dragonflies are fairly common, one of the most ubiquitous in North America.  They live in all Canadian provinces and all US states in North America.  Their range is reduced in arid climates but they are still present where freshwater bodies exist.  As you can imagine, the variation in habitats over that range would likely affect the insect's phenotype (outward genetic expression).  One of the big drivers of adaptation and selection is temperature. As you can see from the above image, male and female whitetailed dragonflies do not look the same; mature adult males have a pronounced white abdomen (juvenile adult males do not) while females have white markings on theirs.  Another difference is in the wings, where the males' are relatively shorter, requiring more effort but also allowing greater manoeuvrability.  This comes in handy when the...
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Lines to live by: Pointing using lines, or the occasional anchor.

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  "The van is easy to find.  There's an arrow on my front lawn pointing to it." OK, it's not an arrow, it's an anchor.  I photographed this in Nelson's Dockyard in Antigua.  But you get the idea that you can use lines to direct your attention to a subject or feature in an image.  The interesting thing here is that it's hard to "unsee" the anchor as being an arrow.  Would it look the same if the van was parked somewhere else? Some photos I have taken where lines play a large part in their impact. You can see the above images all have lines that deal with pointing to some degree.  You can use lines to frame, draw your eye, or enhance some aspect of a photo.  The images above all deal with pointing towards a subject.   Lines can be natural or artificial in nature.  They can come as single entities or multiple ones.  They can be of the same makeup or of many different kinds.  What they should have in common is the ability to s...
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