Monday
Jul042011

The Lighthouse at the Point

I discovered Cape May in 1974 as a result of having read Witmer Stone’s classic Bird Studies at Old Cape May. At the time, I lived in northern NJ, a 3-5 hour (depending on traffic) drive away. In 1989, I moved to southern NJ outside Philadelphia, which put me about 90 minutes from Cape May. Despite the distances, I drove to Cape May about as often as time permitted. I then moved to Texas in 2001, but returned to NJ in early 2010. This time we bought a house in Cape May County about 15 miles from Cape May Point at the southwestern corner of the State.

Cape May Point is easy to find. Take the Garden State Parkway south to Exit 0. Continue straight over the eastern canal bridge onto Lafayette Avenue. Make a right at the “T” intersection in front of Collier’s Liquors onto Perry Street, which soon becomes Sunset Boulevard. After a couple of miles, make a left onto Lighthouse Avenue, which will take you to Cape May Point State Park.

There were two other lighthouses at the southwestern tip of New Jersey. Both of these were lost; one to the unrelenting ocean and the other to poor workmanship. The first was built in 1823 while the second was built in 1847. The current one was finished in 1859.

The Park is justly famous in the natural history community as the sight of the annual Cape May Hawk Watch. However, it is the Cape May Point Lighthouse that dominates the Park. The Lighthouse is 157 feet 6 inches tall with 217 steps (199 indoors) to the observation deck. Not surprisingly, given the flatness of Cape May, the Lighthouse is a very prominent landmark visible from many areas around the Point. As a result, it is often a photographic subject for the weekly photo walks I lead for the Cape May Bird Observatory.

The lighthouse image at the upper left is a scan of a slide made with a Nikon N90s camera with a Nikon 35-105mm lens and Sensia 100 film. The image at the upper right was created with a Canon 7D camera, a Canon EF 300mm f/2.8 lens, an ISO of 500, an aperture of f/5.6, a shutter speed of 1/1000, and an exposure compensation of +1.0. The image to the left was created with a Canon EOS 1D Mark IV camera, a Canon EF 100-400mm f/4.5-5.6 lens, an ISO of 400, an aperture of f/14, a shutter speed of 1/500, and an exposure compensation of +0.33. The image to the right was created with a Canon EOS 1D Mark IV camera, a Canon EF 28-70mm f/2.8 lens, an ISO of 1600, an aperture of f/4.0, a shutter speed of 1/3200, and an exposure compensation of +1.33. The image at the lower left was created with a Canon 7D camera, a Canon EF 28-70mm f/2.8 lens, an ISO of 800, an aperture of f/5.0, and a shutter speed of 1/5000. The image to the right of that one was created with a Canon 7D camera, a Canon EF 300mm f/2.8 lens with a Canon 2.0x III teleconverter, an ISO of 500, an aperture of f/5.6, and a shutter speed of 1/2000. The next one to the right was created with a Canon 7D camera, a Canon EF 600mm f/4.0 lens with a Canon 1.4x III teleconverter, an ISO of 500, an aperture of f/5.6, and a shutter speed of 1/320. The image to the lower right was created with a Canon 7D camera, a Canon EF 28-70mm f/2.8 lens, an ISO of 800, an aperture of f/5.6, and a shutter speed of 1/8000.

As these images show, I have photographed the Lighthouse in the snow, from the beach in Winter, and from south of Bunker Pond in Summer. Likewise, as noted above, I have used lens of various focal lengths that allow very different perspectives. Regardless, the Cape May Point Lighthouse is always an interesting subject for those of us who photograph in the field. Why not join us for a Saturday Photo Walk. For details, see: http://www.birdcapemay.org/programs.php.

Mike Hannisian

Friday
Jul012011

Patagonia Picnic Table Effect Comes to Cape May (Yet Again)

In 1971, the first U.S. record of a Back-capped Gnatcatcher was discovered at a picnic table at a roadside rest area in Patagonia, Arizona. Word got out and shortly thereafter a number of birders descended on the area to see this record bird. Not only did they relocate the gnatcatcher, but they also discovered the first U.S. record of a Yellow Grosbeak.

During a regularly scheduled Cape May Bird Observatory Friday evening walk at the South Cape May Meadows last summer, led by CMBO Associate Naturalist Karl Lukens and assisted by a number of other CMBO volunteers including myself, the Patagonia Picnic Table Effect, as the above became known, reoccurred; twice.

The first time began when this year’s CMBO Morning Flight Counter Tom Johnson told our group of a Sora a few yards ahead of us. We quickly moved up and shortly were entertained by a Sora that apparently had not read the part of the Rail Instruction Manuel about being secretive. Not only that, but this individual, who was jumping around and otherwise acting strangely, was then joined by another.

Many of our field trip participants had not seen a Sora before, or at least had not seen one well or in a long time, so we spent a good amount of time making sure everyone was able to get protracted spotting scope views of at least one of these birds. While this was happening, I started scanning the area and eventually came upon a duck half hidden in the vegetation. The vast majority of the ducks in this area were Mallards, in various forms of molt, but the bird I had just spotted looked different. All I could see of the bird was its chestnut lower chest and black on its belly and under its tail. I did not need to see more to know that this was one of the three Black-bellied Whistling-Ducks that had been found on July 18 by Kathy Horn. (Later a 4th one joined the group.)

Had we not spent so much time looking at the Sora, and had there not been so many of us searching the birds present, this rarity would almost certainly have been missed.

A little while later, we were on the beach checking out the America Oystercatcher, Least Tern, Ruddy Turnstone, Piping Plover, etc., when Chuck Slugg, also one of our leaders, called us back up the path. On the upper beach, amid all the Semipalmateds (Plovers and Sandpipers), were a pair of Yellow-headed Blackbirds. Again, had we not spent so much time checking out the other birds on the beach, and had there not been so many of us actively looking, we would almost certainly not have found these western wanderers.

The lesson to be learned from all this is that very often there are more good birds around, regardless of where you are, if you take the time to find them; and the more eyes looking the greater the likelihood of finding good birds.

NOTE: The images with this entry were not taken at the bird walk discussed above.

 

 

Friday
Jul012011

Shooting Gulls and Dolphins from a Boat

Nancy and I, along with Nancy's daughter and a friend of hers, spent 2 hours and 40 minutes on a local Dolphin and Whale Watching boat last weekend. (It was to be a 3 hour trip, but we left 20 minutes late, with no explanation or apology. I was also told at the ticket booth that day that the trip would be primarily for large whales, not dolphins. However, we spent 30-40 minutes looking for large whales - without success - while the rest of the time was spent with the dolphins.) As is typical at this time of year at Cape May, NJ, Laughing and Herring Gulls followed the boat to see if its propellers dislodged anything they could eat. As a result, we had an opportunity to shoot these species in flight at near eye level against a fairly uniform sky.

The significance of the sky is that autofoucsing on birds in flight is best against a featureless background, and this sky afforded that. I was using a Canon 7D camera with a Canon EF 300mm f/2.8 lens. I set the camera's focus for "Ring of Fire" which includes all 19 of the potential focus points. I also, via a custom function, had moved the autofocus from the shutter button to the middle of the three buttons on the upper right of the back of the camera. The reason for this is that I can recompose an image after I have acquired focus and not have that focus changed by my pressing the shutter button.

Another consideration in such situations is to add a stop of light, perhpas more, to the reading the exposure meter suggests. The reason for this is that the meter wants to make the bright sky a mid-tone by cutting off the amount of light reaching the sensor. In turn, this will make the subject, which is not as bright as the sky, that much darker. This is compensated for by adding a stop of light or so via exposure compensation. Just be certain to check your histogram to see that you have achieved a good exposure. Also remember to ETTR (expose to the right).

Exposing to the right is warranted because, in general, an optimum digital exposure is acheived by adding the amount of light to the image necessary to cause the histogram to be as far right as possible without hitting the right edge. This will often cause the image on the LCD screen on the back of the camera to blink allegedly indicating an over-exposure. However, that image is a JPEG and given that you are shooting in RAW (if you are at all serious about your work), the LCD image will be misleading.

I have heard photographers say that they don't try to shoot birds in flight because they do not have image stabilized lenses. This shows a lack of understanding of the situation. When shooting birds in flight, you pan the lens with the bird. As a result, image stabilization is not relevant. (As an aside, I always leave my image stabilization on as it does no harm when not needed.)

The problem with creating good images of dolphins, in this case the Atlantic Bottlenose Dolphin, is that you do not have enough time to 1) see them come up to breathe, 2) find them in your camera, 3) focus on them, and 4) take the shot before they are back under water. As a result, most dolphin images show, at best, the back or tail of a submerging dolphin.

The ideal situation is to have the sun at your back and a group of dolphins at the surface in front of you. Set your ISO high enough so that yu can shoot at a fairly fast shutter speed, and set you camera to its fastest continuous shooting mode. Then, when a pod surfaces, focus and shoot as fast as you can. On this trip, I shot over 300 dolphin images, and was lucky enough to get 2 good ones.

As you can surmise, this may not be an efficient way to photograph, but it is the best way I know to increase the likelihood of capturing the shot you want. After all, with the price of pixels being what it is, just keep shooting. (I consider it a good day when I have created 1 or 2 high quality keepers.) The trick is to have a large capcity, high speed CF card, and these are now readily available. For example, I recently bought a 32 GB, 600x CF card for $175.00.

The bottom line is to know your equipment thoroughly, properly set your camera's exposure based on its histogram (not on the JPEG image on the LCD screen), have a fast large capacity card in your camera, and shoot, shoot, shoot! Once you are comfortable with these techniqes, you can use them for other species in similar situations.

Friday
Jul012011

Proper Exposure

There is no such thing as a precise definition of proper exposure because it is an inherently subjective matter. This is because an image is properly exposed if and only if the exposure is the way you, as the artist/photographer, want it to be.

Yes, I know, in and of itself, this is not very helpful, but it is nonetheless true.

Keep in mind, that as the photographer, you are the creative artist making the images, and that necessarily means that it is you, and only you, who should have the final word on how the image looks. This is not to say that there are not photographic or image standards; rather, it means that as the artist in charge you are the one who chooses how to apply (or disregard) them.

Be that as it may, most photographers who are attempting to create images that approximate what they saw generally think of proper exposure as recording the amount of light required for the image to exhibit good detail in the darkest shadows and in the brightest non-specular areas. (Specular areas are pure white regions that contain no detail, such as highlights on a reflective metal surface.)

For a number of the photographers, especially those who did not shoot reversal (slide) film, exposure is not a conscious issue because they just set the camera to auto and shoot. This can work reasonably well when there is relatively little contrast within the frame and the scene/subject is mid-toned. The reason for this is that virtually all light meters provide settings based upon the assumption that your subject is a mid-tone. That means your meter assumes your subject is reflecting the same amount of light as an 18% gray card would reflect, even when using evaluative, sometimes called matrix, metering (which I do virtually all of the time).

Not surprisingly, this is often not the case. Consider, for example, that you are photographing a breeding plumaged Laughing Gull on a white sand beach or against a bright sky. Your meter will give you a reading that is likely to blow out the whites in the gull, sand, or sky; or darken the image to such an extent that the black hood and mantle of the gull will be featureless. (The differing results depend upon the lighting and the size of the subject in the frame, among other factors.) Further compounding the situation is the fact that the quality level of much of today’s photography has become decidedly mediocre as a result, in significant part, of inexpensive cameras, the ease with which camera processed images (JPEGs) can be uploaded and distributed, and the failure of many photographers to want to improve the quality of their work.

There is also the all-too-common attitude that most, if not all, photographic problems can be fixed in Photoshop. While it is true that Photoshop and other image editing software are wonderful for enhancing images, it is just as true that few problems can be fully corrected in them and those that can require much more time and effort than getting it right in the camera. For example, if I were to over expose an image to the point that little or no detail were recorded in highlight areas, there is nothing that any program can do to recover data that were not recorded. Likewise, if I were to underexpose an image but not so severely as to have no detail, correcting the exposure with software would almost certainly result in a significant increase in noise. (Noise comes in two types: color and luminance. Color noise is the presence of off-color pixels while luminance noise is the presence of overly bright or overly dark pixels.) Always keep in mind that a basic rule of digital photography is to rely on Photoshop, or any other image processing software, as little as possible!

Achieving a proper exposure is a matter of balancing the three exposure variables: ISO, shutter speed, and aperture. However, achieving the desired result requires knowing what you want and balancing these variables in order to achieve this end.

I suggest that you first decide on the ISO you want to use.

Most of my photography is of birds and, typically, I want to capture them doing something. This means I need to stop their action. This is one area in which digital is far superior to film. With film, I almost never used an ISO higher than 200. With digital, my normal ISO setting is 500, and I am not reluctant to shoot at an ISO of 6400. Although these higher settings can produce noise, it is relatively minor given the cameras I use (Canons 7D and 1D Mark IV). The reason I choose such a high ISO is so I can shoot at a small aperture to increase the depth of field. (Depth of field is the portion of the image, front to back, that is in focus.)

I often want my subjects to be large in the frame. One of the realities of this is that the larger the subject in the frame, the more shallow the depth of field. This is especially true when you use long lenses with teleconverters, as I frequently do. Thus, I use a relatively high ISO in order to allow me to use a smaller aperture with its associated greater depth of field.

However, if I were shooting a stream and wanted to create an image in which only the water was out of focus, I would use a low ISO. This way, even with a small aperture, which would cause the non-moving parts of the image to be in focus, the moving water would be blurred with a slow shutter speed. (This, of course, would require that the camera be mounted on a tripod.)

As you can see, there is no formula for choosing an ISO. You, as the photographer, must know what you want to create and then select the ISO most likely to help you achieve it.

Once I have decided on my ISO, I then have to decide the camera mode I want to use. Usually, for the work I do, this is AV, which stands for aperture value. What this means is that I determine the aperture I want to use, and the camera then decides which shutter speed to use. Just keep in mind that, as the photographer, I have the option of altering the camera’s choice.

For example, if I am shooting a mid-toned scene/subject in full sunlight, I am likely to use the settings the camera offers. On the other hand, on a cloudy/overcast day, the camera is likely to select settings that will underexpose lighter than mid-toned scenes/subjects so I add light via the camera’s exposure compensation function. Conversely, on a cloudy/overcast day, the camera is likely to select settings that will overexpose darker than mid-toned scenes/subjects so I subtract light via the camera’s exposure compensation function. How much light I add or subtract depends upon the conditions and the size of the subject in the frame. When I shot film, I would make my best guess and then take a series of photos making some a little brighter than I thought would work and some a little darker. I then had to wait until I received the developed film back to see if I made the right choice, and with no realistic option to correct any mistake.

Digital photography makes this a much easier process because of the histogram function included in most of today’s digital cameras. Thus, after I made my best guess/judgment, I check the histogram to see if I was correct. If so, fine; if not, I make another adjustment and check it again. (I will explain how to read and use histograms in a future posting.)

Again, my goal in shooting birds usually is to capture them doing something (not just sitting there), and often against a non-distracting background. A good way to do this is to shoot against a smooth, pleasing, mid-toned background. However, if this background is close to the subject and I use a small aperture, I run the risk of having enough detail in the background for it to become a distraction. Thus, I like to have a significant separation (20 feet or more) between my background and my subject. As a result, I prefer to shoot with an aperture of f11 to f16, depending on the lens, subject, and other factors. Paramount among these other factors is shutter speed, because I still want to freeze the subject’s action. If, for some reason, I cannot separate the subject from the background, I will use a larger aperture (smaller f number) to reduce the detail in the background.

Again, you as the artist/photographer have to decide what it is you want to achieve and then choose the aperture most likely to produce these results.

Not surprisingly, choosing a shutter speed is no different.

If you are trying to freeze a bird in flight without panning (moving the camera to keep the subject in the same position within the frame), you typically need a shutter speed of 1/2500 of a second or faster! In other words, you may have to raise your ISO and/or open your aperture depending on the light. However, by panning you can slow the shutter to freeze the action so long as you are able to keep the subject in focus. While this has been made significantly easier with state of the art autofocus technology, it still requires practice and choosing a shutter speed that will facilitate the desired result.

For panning flight shots, I like to have a shutter speed of at least 1/2500 of a second.

I also do a fair amount of bird photography from blinds. In such situations, I prefer to create a limited number of perches in front of pleasing backgrounds and near feeding or water features. In situations such as these, I will often use a shutter as slow as 1/125 of a second.

Again, one of the big advantages of digital photography is the ability to take an image and almost immediately review it. True, to see it well it must first be downloaded to a computer, but the LCDs on the back of mid to high-end DSLRs give a reasonable in-the-field view so that you should be able to get a decent sense of whether or not you are using a faster enough shutter speed.

In conclusion, you and only you are the artist/photographer and, as such, it is your responsibility to balance the exposure variables of ISO, aperture, and shutter speed to achieve the exposure you desire.

 



Friday
Jul012011

Stop! (F-stop, that is)

All disciplines have their own vocabulary, and photography is no different.

In an earlier entry, I defined ISO, shutter speed, and aperture. A concept related to all of these is the f-stop or simply “stop”. Stop is used in all areas of photography, and is a convenient means of denoting the relative change in the amount of light or the sensitivity to light. It is relative because it requires an arbitrary starting point, and then measures any change from that point. Every time the amount of light, or an object’s (film or sensor) sensitivity to it, changes by a factor of 2, a new stop is achieved. (Many modern digital cameras permit changes of ½ and/or ⅓ of a stop.)

Before we continue, let’s make certain that we understand what “a factor of 2” means.

Factor means to multiply or divide. The reason factor also means divide is that division is multiplying by a reciprocal. For example, to divide something by 2 means to multiply it by the reciprocal of 2 (i.e.: ½). Thus, dividing 8 by 2 is the same as multiplying 8 by ½. (Remember, in arithmetic, the word “of” means multiply.) So when we ask what is ½ of 8, we are asking what do you get when you multiply 8 by ½ which, in turn, is the same as asking what do you get when you divide 8 by 2. Thus, changing something by a factor of 2 means doubling it or halving it, depending upon whether more or less light (or light sensitivity) is involved. The number of stops tells you how many times to multiply or divide the original measure by 2.

Suppose the lighting conditions are such that the exposure you desire can be achieved by using an ISO of 200, a shutter speed of 1/250th of a second, and an aperture of f8.0. If the light were to become twice as bright, an increase of one stop, you would have to lower your ISO by one stop to 100, or increase your shutter speed one stop to 1/500th of a second, or reduce your aperture one stop to f11. Each of these would decrease the amount of light reaching your film or sensor by one stop. Realize that if you did all three, you would reduce your exposure by 3 stops.

Take the example above (ISO of 200; shutter speed 1/250th, and aperture of f8.0) and consider the effect of an increase in the light so that it were 4 times as bright. Many new photographers assume that this is an increase of 4 stops because the light became four times brighter. However, it is an increase of only 2 stops. Remember, an increase of 1 stop doubles the light. If that light is doubled again (2 times 2), it is now 4 times as bright as it was originally; hence 4 times the original brightness is an increase of 2 stops. Thus, your desired exposure can be achieved by lowering your ISO two stops to 50, or increasing your shutter speed two stops to 1/1000th of a second, or reducing your aperture two stops to f16. Keep in mind that doing all 3 would be a decrease of 6 stops, or a reduction in the amount of light reaching your film or sensor by a factor of 64!

Most modern cameras do a decent job of predicting a reasonable exposure under typical circumstances, and many people are satisfied with this. Just keep in mind that if you aim to exceed the ordinary, you cannot rely upon your camera’s light meter (or any other light meter for that matter) under all circumstances. You need to be able to adjust one or more of the three exposure variables in accord with conditions. To fully understand how to do this, a full understanding of stops is required and this involves the concept of exponents.

(If you are convinced that understanding exponents is beyond your ability, there is little I or anyone else can do to help you. However, if you are willing to follow a basic, step-by-step explanation, you can understand exponents. True, it may/should take some thought and, if your arithmetic skills are weak, more than one reading, but only you can decide if your photography is worth the effort.)

Just as multiplication is a short cut to addition (3 + 3 + 3 + 3 is the same a 3 x 4; both equal 12), exponents are a short cut to multiplication. For example, 2 x 2 x 2 x 2 is the same as 2 to the 4th power ( 2⁴); both equal 16. (2 x 2 = 4; 2 x 4 = 8; 2 x 8 = 16.)

So far so good, but how do you get ½, ¼, ⅛, etc., out of an exponent of 2 (2 to some power)?

The answer to this can be illustrated by considering what you get if you take 2²and divide it by 2⁴. Realize that all this means is 2 x 2 (4) divided by 2 x 2 x 2 x 2 (16) or 4/16 = ¼ (1 divided by 4). In arithmetic terms, this means 1 divided by 2²(1/2²= ¼).

Okay, so how does this relate to stops?

If, for example, you need to reduce your shutter speed of 1/500th of a second by 2 stops, you need to change it to 1/500 times 2²(4/500 = 1/125).  One-way of doing this is to divide 500 by 2 twice: 500/2 = 250; 250/2 = 125. Then express this as the fraction 1/125. Thus, a 2-stop decrease from 1/500th of a second is 1/125th of a second. Another way of doing this is to divide 500 by 2²(500/4) which, not surprisingly, also yields 125 which, in turn, equates to 1/125th of a second.

I explain the above because, as noted wildlife photographer John Shaw points out, a full understanding of exposure is essential for creating outstanding photos.

Again, if you are satisfied with images that are adequately exposed most of the time, your camera’s meter will work reasonably well. However, if you want your images to stand out from the mediocrity that seems to impress so many today, you need to take the time to understand exposure. While this may seem excessive to some, keep three points in mind:

1)    A year from now you will be a year older, whether you have taken the time to learn something new (such as exposure) or not;

2)    The histogram feature of digital photography allows you to quickly check your exposures and to easily modify them as needed; and

3)    Take photography classes (where you get to ask questions not just read text), but make certain that all of the basics are covered in detail!

If you need further incentive to improve your photography, take a look at the images of such wildlife photographers as Paul Denman (www.pmdphoto.com/PMDPhoto), Arthur Morris (www.birdsasart.org), Alan Murphy (www.alanmurphyphotography.com), Larry Ditto (www.larryditto.com), Kevin T Karlson (www.kevinkarlsonphotography.com), Kevin J Hurt (www.hurtphoto.com), and those who have shot at deep south Texas’s Dos Venadas Ranch (www.dosvenadas.com/gallery.htm), etc.

Remember, the only one holding you back is yourself!

In summary, f-stops (or simply stops) are factors of 2. If the brightness or sensitivity to light doubles, that is an increase of one stop (times 2); if the brightness or sensitivity to light is halved, that is a decrease of one stop (divided by two).