Saturday, August 13, 2011
Wildfire!
Being evacuated from your home is never a good thing. But, in those times, you just have to make the best of it. For me, photography of the very disaster that chased us out was my outlet. Images of the Las Conchas Fire.
Photographing the Petroglyphs of Northern New Mexico
Photographing petroglyphs can be a horrible challenge. It's too bright, the lighting angle is wrong, the light is too soft or too harsh, etc. Waiting for just the right lighting or trying to modify with filters just never quite does it. Nope, the best results are had using strobes. In this example, three Canon 580exII strobes are used to light the petroglyphs at an angle that makes them stand out, and at the same time reduce the key of the overall photo just a touch.
Without strobes:
You can play with the brightness and contrast in Photoshop, but you'll never get the petroglyphs to show much better. The glare from the natural sunlight is too much. A polarizer helps, but not really to the extent desired.
Adding two 580EXIIs camera left (handheld) to light the petroglyphs of the large boulder and one 580EXII behind the large boulder to light the large spiral on the rear boulder (strobes triggered by PocketWizards and ratio controlled by AC3 Zone Controller) provides a better result.
EF 24-70 f/2.8L USM at 25mm, Canon 5D Mk II, ISO 100, 1/100th, and f22
With strobes:
Specifics:
It just goes to show, you can never have too much gear in the field! (But you do need a strong back and legs to get it there!)
Without strobes:
You can play with the brightness and contrast in Photoshop, but you'll never get the petroglyphs to show much better. The glare from the natural sunlight is too much. A polarizer helps, but not really to the extent desired.
Adding two 580EXIIs camera left (handheld) to light the petroglyphs of the large boulder and one 580EXII behind the large boulder to light the large spiral on the rear boulder (strobes triggered by PocketWizards and ratio controlled by AC3 Zone Controller) provides a better result.
EF 24-70 f/2.8L USM at 25mm, Canon 5D Mk II, ISO 100, 1/100th, and f22
With strobes:
Specifics:
It just goes to show, you can never have too much gear in the field! (But you do need a strong back and legs to get it there!)
Saturday, April 30, 2011
Diversity Within The Species
As I continue my quest to complete my book on the lizard species of New Mexico, I periodically find myself in awe of the overall diversity in species that have adapted for life in the varried regions of the state. Recently, I have had the pleasure of close examination and study of the species Holbrookia maculata, the lesser earless lizard. The diversity across this species and across the sexes is impressive. And, I have yet to run across the longer-tailed variety of the extreme southwest corner of the state. (See my previous blog regarding my issues accessing this part of New Mexico.)
Holbrookia maculata ruthveni:
The adaptation of the narrow-ranged ruthveni subspecies to the unique white gypsum sands of Dona Ana and Otero counties of New Mexico through evolution of a bleached out appearance, is an obvious benefit. Combine the extent to which they blend with the substrate and their incredible ability to burrown into the sand in the blink of an eye and you certainly have a lizard poised for success!
White Sands
Subspecies ruthveni Specimen from White Sands
Burrowing under!
Periscope up!
Holbrookia maculata approximans:
Across most of the balance of New Mexico, and especially in the brown Mescalaro Sands, the subspecies is Holbrookia maculata approximans. This subspecies demonstrates dramatic sexual dimorphism. The female is quite vividly colored. Hager1 provides evidence that changes in coloration of the female are used as an indicator for males of her receptiveness to coppulation. Surely, this benefit must outweigh the negative camoflage aspects of this same coloration.
Subspecies approximans, brightly colored female from the Mescalaro Sands
Same female showing subdued (receptive) coloration
Subspecies approximans, a male from the Mescalaro Sands
References:
Holbrookia maculata ruthveni:
The adaptation of the narrow-ranged ruthveni subspecies to the unique white gypsum sands of Dona Ana and Otero counties of New Mexico through evolution of a bleached out appearance, is an obvious benefit. Combine the extent to which they blend with the substrate and their incredible ability to burrown into the sand in the blink of an eye and you certainly have a lizard poised for success!
White Sands
Subspecies ruthveni Specimen from White Sands
Burrowing under!
Periscope up!
Holbrookia maculata approximans:
Across most of the balance of New Mexico, and especially in the brown Mescalaro Sands, the subspecies is Holbrookia maculata approximans. This subspecies demonstrates dramatic sexual dimorphism. The female is quite vividly colored. Hager1 provides evidence that changes in coloration of the female are used as an indicator for males of her receptiveness to coppulation. Surely, this benefit must outweigh the negative camoflage aspects of this same coloration.
Subspecies approximans, brightly colored female from the Mescalaro Sands
Same female showing subdued (receptive) coloration
Subspecies approximans, a male from the Mescalaro Sands
References:
- Hager, S. B. 2001. The role of nuptial coloration in female Holbrookia maculata: evidence for a dual signaling system. Journal of Herpetology 35[4]:624-632.
Sunday, March 20, 2011
"May I See Some Identification, Please"
Perhaps people have heard these words from an officer during a routine traffic stop (on the Television, of course). In such an instance, the protagonist probably knew he was maybe going a bit fast, or maybe he didn't stop fully at the light, maybe his registration had expired; It is generally assumed that there was an event or a situation that provided probable cause for the officer to detain the driver.
Probable cause, a necessary precursor to a vehicle stop by a law officer. Our First United States Congress, in 1791, felt a need to limit the recourse of government, spawning the first ten amendments to the United States Constitution -- the Bill of Rights. The Fourth Amendment was specifically designed to put limits on the agents of the Government, establishing the need to establish "probable cause" prior to such personal intrusions as detainment, questioning, search, and seizure. Certainly, those uniformed officers sworn to protect our borders would dutifully observe, respect, and uphold this Right?
What I write is a true story; an event that happened to me this past Friday. An event that tries my resolve in my now four-year long quest to publish a book of photographic depictions of all the lizard species inhabitting the state of New Mexico.
Of course, to achieve my goal, I must locate and photograph the 41 species known to inhabit this varried state. Many of these species are only found in the southern reaches, resulting in long-reaching treks to near-border locals, such as those in the bootheal region.
This past Friday, my youngest daughter and I embarked on what was supposed to be an overnight trip to the region south of Deming and Lordsburg. I was particularly interested in tracking down the Yarrow's Spiny Lizard (Sceloporus jarrovii) and, although it is early in the spring, the Canyon Spotted Whiptail (Aspidoscelis burti), the Gray-checkered Whiptail (Aspidoscelis dixoni), Zebra-tailed Lizard (Calisaurus draconoides)and the Sonoran Spotted Whiptail (Aspidoscelis sonorae) were secondary goals. All of these species are fairly restricted in their New Mexico range to this near border area.
Last winter, on a day trip from Las Cruces, I visited this area. I felt like I was in a war zone; there were border patrol vehicles everywhere, and my every move was watched. A momentary stop to observe a white-tailed kite through the binoculars resulted in an almost immediate visit by the Border Patrol, who prevailed to question me on my activity. And, did not seem to hold stock in my truthful answers.
This previous experience on my only prior visit to this area gave me a nagging concern about my plans for the weekend. But, with the area weather forecasted to break 80-degrees F and the opportunity to take a much-needed day off work, we planned the trip. We packed sleeping bags, camera gear, my ever-handy lizard-catching tool (a 9-ft fishing rod with a noose at the end), spare clothes, a few other essentials, and we hit the road at o-dark-hundred. (It's approximately a seven-hour drive to reach this region.)
By about 11:00, we reached Deming and headed southwest turning south on NM 146. We made a short stop at the remains of an old farm where we observed Sceloporus consobrinus and a number of small Aspidoscelis species that just wouldn't cooporate. The flies were unbearable, so we decided to head along our way. We reached NM 9 and headed west towards Animas. Along the way, we stopped for an hour or so to hike the Central Divide trail, checking out some rocky outcroppings for lizards. Although we found no lizards, we were treated to a rather scarce view of a kit fox.
Returning to our vehicle and heading again westward towards Animas, we stopped briefly at an historic marker where I checked the map and GPS before heading into Animas. As we pulled away from the historic marker, a Border Patrol truck pulled in off the road. I continued along my way with the Patrol notably pulling in behind me after a few moments. As we neared the town, a second patrol passed us in the other lane, made a quick u-turn and pulled in behind the first. As we reached the end of the road and proceded to turn north, the following trucks hit their lights and sirens. I, of course, quickly pulled off the side of the road.
As the four officers approached, I rolled down my window. My daughter looked quite perplexed at what was going on. One officer approached my side of the car and asked what we were up to, where we had come from, and where we lived. Of course, my answers, being honest, did not seem to convince the officer who kept going further. At this point, I'm rather irritated, but with my daughter present, I respected the officer's authority; having done nothing wrong, I felt secure in my sense of innocence.
Eventually, the office asked to look inside the back of the vehicle. Of course, the other officers had been peering through windows while the one officer questioned me. At this point, my Fourth Amendment Rights are ringing in my head. Should I press my position of innocence and force this band of officers to come up with charges or seak out a court order? I could be there for hours/days, and what signal would this send my daughter who was clearly a bit unnerved by the event? No, instead I had nothing to hide -- I let them root through the back of the vehicle.
"Are you going to do some fishing?" I was asked as they saw my rod. Of course, I told them that I used the rod to capture lizards to photograph, that I was working on a book. That hardly slowed them down as they squeezed my sleeping bags and our backpacks. Finally, the officer still holding my license returned it to me and told me we were free to go. So, I then asked why we had been detained. His answer, "Because of the direction we were driving." So, driving "west" is apparently considered "probable cause"?
Let's reflect for a moment the mission of the Border Patrol, as indicated on their web site:
Prey tell, how does this illegal detainment fit into that mission? How is it this Gastapo-like approach is allowed?
No matter that these civil-rights violating, albeit polite, hooligans allowed me to go along my way, they violated the rights endowed me in the United States Constitution. I feel denied my right to be secure in my person and effects, to the point that I believe a part of my state and country has been denied me.
As we drove away, I appologized to my daughter for the freedoms infringed and impressed upon her the hope that her generation does far better than mine and my parents with respect to protecting, upholding, and enforcing our Constitutional Rights. We headed home after speding only a couple hours in the region we had driven 7 hours to explore for lizards.
Spending the night in this area was to me clearly out of the question, as was heading any further south towards the border or the Coronado National Forest where we had intended to camp. Strangely, it is not the illegal aliens or the drug smugglers I fear, but the officers of my own government. If asked today, I would tell you that I will not return to Hidalgo County, New Mexico; to complete my book may require other means, if I am able to complete it at all.
I am reminded of the words of Thomas Jefferson, "The two enemies of the people are criminals and government, so let us tie the second down with the chains of the Constitution so the second will not become the legalized version of the first." It appears we have failed to hold our government in check. Liberty is falling. One thing is certain. If or when I complete this project, the forward will discuss the new age Gestapo, The Department of Homeland Security.
Probable cause, a necessary precursor to a vehicle stop by a law officer. Our First United States Congress, in 1791, felt a need to limit the recourse of government, spawning the first ten amendments to the United States Constitution -- the Bill of Rights. The Fourth Amendment was specifically designed to put limits on the agents of the Government, establishing the need to establish "probable cause" prior to such personal intrusions as detainment, questioning, search, and seizure. Certainly, those uniformed officers sworn to protect our borders would dutifully observe, respect, and uphold this Right?
What I write is a true story; an event that happened to me this past Friday. An event that tries my resolve in my now four-year long quest to publish a book of photographic depictions of all the lizard species inhabitting the state of New Mexico.
Of course, to achieve my goal, I must locate and photograph the 41 species known to inhabit this varried state. Many of these species are only found in the southern reaches, resulting in long-reaching treks to near-border locals, such as those in the bootheal region.
This past Friday, my youngest daughter and I embarked on what was supposed to be an overnight trip to the region south of Deming and Lordsburg. I was particularly interested in tracking down the Yarrow's Spiny Lizard (Sceloporus jarrovii) and, although it is early in the spring, the Canyon Spotted Whiptail (Aspidoscelis burti), the Gray-checkered Whiptail (Aspidoscelis dixoni), Zebra-tailed Lizard (Calisaurus draconoides)and the Sonoran Spotted Whiptail (Aspidoscelis sonorae) were secondary goals. All of these species are fairly restricted in their New Mexico range to this near border area.
| Distribution of S. jarrovi in New Mexico |
 |
Last winter, on a day trip from Las Cruces, I visited this area. I felt like I was in a war zone; there were border patrol vehicles everywhere, and my every move was watched. A momentary stop to observe a white-tailed kite through the binoculars resulted in an almost immediate visit by the Border Patrol, who prevailed to question me on my activity. And, did not seem to hold stock in my truthful answers.
This previous experience on my only prior visit to this area gave me a nagging concern about my plans for the weekend. But, with the area weather forecasted to break 80-degrees F and the opportunity to take a much-needed day off work, we planned the trip. We packed sleeping bags, camera gear, my ever-handy lizard-catching tool (a 9-ft fishing rod with a noose at the end), spare clothes, a few other essentials, and we hit the road at o-dark-hundred. (It's approximately a seven-hour drive to reach this region.)
By about 11:00, we reached Deming and headed southwest turning south on NM 146. We made a short stop at the remains of an old farm where we observed Sceloporus consobrinus and a number of small Aspidoscelis species that just wouldn't cooporate. The flies were unbearable, so we decided to head along our way. We reached NM 9 and headed west towards Animas. Along the way, we stopped for an hour or so to hike the Central Divide trail, checking out some rocky outcroppings for lizards. Although we found no lizards, we were treated to a rather scarce view of a kit fox.
Returning to our vehicle and heading again westward towards Animas, we stopped briefly at an historic marker where I checked the map and GPS before heading into Animas. As we pulled away from the historic marker, a Border Patrol truck pulled in off the road. I continued along my way with the Patrol notably pulling in behind me after a few moments. As we neared the town, a second patrol passed us in the other lane, made a quick u-turn and pulled in behind the first. As we reached the end of the road and proceded to turn north, the following trucks hit their lights and sirens. I, of course, quickly pulled off the side of the road.
As the four officers approached, I rolled down my window. My daughter looked quite perplexed at what was going on. One officer approached my side of the car and asked what we were up to, where we had come from, and where we lived. Of course, my answers, being honest, did not seem to convince the officer who kept going further. At this point, I'm rather irritated, but with my daughter present, I respected the officer's authority; having done nothing wrong, I felt secure in my sense of innocence.
Eventually, the office asked to look inside the back of the vehicle. Of course, the other officers had been peering through windows while the one officer questioned me. At this point, my Fourth Amendment Rights are ringing in my head. Should I press my position of innocence and force this band of officers to come up with charges or seak out a court order? I could be there for hours/days, and what signal would this send my daughter who was clearly a bit unnerved by the event? No, instead I had nothing to hide -- I let them root through the back of the vehicle.
"Are you going to do some fishing?" I was asked as they saw my rod. Of course, I told them that I used the rod to capture lizards to photograph, that I was working on a book. That hardly slowed them down as they squeezed my sleeping bags and our backpacks. Finally, the officer still holding my license returned it to me and told me we were free to go. So, I then asked why we had been detained. His answer, "Because of the direction we were driving." So, driving "west" is apparently considered "probable cause"?
Let's reflect for a moment the mission of the Border Patrol, as indicated on their web site:
| "The priority mission of the Border Patrol is preventing terrorists and terrorists' weapons, including weapons of mass destruction, from entering the United States. |
Prey tell, how does this illegal detainment fit into that mission? How is it this Gastapo-like approach is allowed?
No matter that these civil-rights violating, albeit polite, hooligans allowed me to go along my way, they violated the rights endowed me in the United States Constitution. I feel denied my right to be secure in my person and effects, to the point that I believe a part of my state and country has been denied me.
As we drove away, I appologized to my daughter for the freedoms infringed and impressed upon her the hope that her generation does far better than mine and my parents with respect to protecting, upholding, and enforcing our Constitutional Rights. We headed home after speding only a couple hours in the region we had driven 7 hours to explore for lizards.
Spending the night in this area was to me clearly out of the question, as was heading any further south towards the border or the Coronado National Forest where we had intended to camp. Strangely, it is not the illegal aliens or the drug smugglers I fear, but the officers of my own government. If asked today, I would tell you that I will not return to Hidalgo County, New Mexico; to complete my book may require other means, if I am able to complete it at all.
I am reminded of the words of Thomas Jefferson, "The two enemies of the people are criminals and government, so let us tie the second down with the chains of the Constitution so the second will not become the legalized version of the first." It appears we have failed to hold our government in check. Liberty is falling. One thing is certain. If or when I complete this project, the forward will discuss the new age Gestapo, The Department of Homeland Security.
Saturday, March 5, 2011
Lesson 2: Composing Perspectives
Another lesson for my TQ friends...
When an image grabs your attention, stop and ask yourself why. I expect that most of the time, the answer has to do with a unique, different, or compelling perspective. For powerful images, perspective is one of the most influential tools the photographer has in his aresenal -- the others being control of light and color, selection of depth of view, and the representation of motion. In this lesson, I will focus on some general considerations (their really are no "rules") for rendering a 3D scene into a 2D format.
The "Rule" of Thirds
You have perhaps heard of the so called "Rule of Thirds". This "rule" is simple, but very powerful, and following it will quickly result in improved image composition. In general, the idea is to place your main subject off center both top-to-bottom and side-to-side such that it is framed about 1/3 the frame width from one side and about 1/3 the frame height from either top or bottom. Additionally, the subject should then lead the viewer into the image. This representation creates a dynamic image composition. Of course, rules are made to be broken and this one is really more of a guideline than a rule. The point is to try not to fall victim to the common trap of always centering your subject. Centering the subject is an easy thing to do since most of us use the center focus point to autofocus the subject, and remembering to recompose before snapping the image is not always natural. Your goal here is to discipline yourself to focs and then always consider recomposing the frame before tripping the shutter. Here's a few example images to consider the effect the composition has on the overall impact.
Keep your subject off-center for greater impact; try to keep the overall flow in towards the center of the image.
Get Into It!
It is often important for the artist to sacrifice for the shot. When you want an image to stand out from the crowd, you need to do the same. Think about unique angles for protraying your subject. Be prepared to sprall on the ground or climb a tree (be mindful of safety and other considerations, please) if that is what it takes to get the shot. Putting yourself out there is often the difference between an impactful image and one that falls dead. Often, photographers will put their models through amazing feats to get the shot, but wouldn't think of doing similar gymnastics themselves!
These images were all taken with me laying on the ground. In the balloon shot, I was actually on the ground, flat on my back.
The Effect of Focal Length
Composition of the subject within the frame is just one component of perspective to consider. Another powerful tool is focal length selection. Focal length selection can have a dramatic effect on the final image. Not only does it have a marked effect on DOF, but it allows you to compress or expand the background. Moving to a longer focal length, you'll find that you can be more selective of the background whereas a wide-angle lens will show all, making it harder to eliminate distracting background elements.
Focal length also has an effect on the feel of the image. Short focal length lenses from about 24mm (35mm full-frame reference) and down will begin to distort the image, bending straight lines in a fisheye manner, especially at the edges of the frame. This can be very appealing in certain instances, such as architectural photography and certain scenics. Combined with a high DOF (small aperture), imagery with these lenses can take on a real different feel.
This image was taken with a 24-70mm zoom lens at 24mm. The wide angle and high aperture accentuates the leg and provides an element to draw the viewer into the image.
Of course, long focal length lenses provide a means to get close without encroaching on your subject, which makes them ideal for wildlife photography. But because these lenses also allow the photographer to compress the background or highlight what would otherwise be almost inconsequential elements of the background, they are often used in on-location portrait work as well. Consider how to render a sunset behind a model on the beach. A wide angle will show a broad range of the horizon, the setting sun being a small part of that horizon; whereas, using a telephoto, the sun can be a second focal point for the image.
This image was taken with a 70-200mm zoom lens at 98mm. The longer focal length allowed me to select a small set of Christmas lights as the background.
Your Asignment
For this lesson, you will shoot and post at least 3 images.
Image 1:
Find a willing (or inanimate) subject and compose a picture demonstrating use of the "rule of thirds".
Images 2 and 3:
Again, with your willing (or unable to do otherwise) subject, shoot images at two different focal lengths. The objective is to observe the effect on the background. Longer focal lengths will compress the background whereas short focal lengths will expand the background. Post a couple shots that dramatically demonstrate this effect.
When an image grabs your attention, stop and ask yourself why. I expect that most of the time, the answer has to do with a unique, different, or compelling perspective. For powerful images, perspective is one of the most influential tools the photographer has in his aresenal -- the others being control of light and color, selection of depth of view, and the representation of motion. In this lesson, I will focus on some general considerations (their really are no "rules") for rendering a 3D scene into a 2D format.
The "Rule" of Thirds
You have perhaps heard of the so called "Rule of Thirds". This "rule" is simple, but very powerful, and following it will quickly result in improved image composition. In general, the idea is to place your main subject off center both top-to-bottom and side-to-side such that it is framed about 1/3 the frame width from one side and about 1/3 the frame height from either top or bottom. Additionally, the subject should then lead the viewer into the image. This representation creates a dynamic image composition. Of course, rules are made to be broken and this one is really more of a guideline than a rule. The point is to try not to fall victim to the common trap of always centering your subject. Centering the subject is an easy thing to do since most of us use the center focus point to autofocus the subject, and remembering to recompose before snapping the image is not always natural. Your goal here is to discipline yourself to focs and then always consider recomposing the frame before tripping the shutter. Here's a few example images to consider the effect the composition has on the overall impact.
Keep your subject off-center for greater impact; try to keep the overall flow in towards the center of the image.
Get Into It!
It is often important for the artist to sacrifice for the shot. When you want an image to stand out from the crowd, you need to do the same. Think about unique angles for protraying your subject. Be prepared to sprall on the ground or climb a tree (be mindful of safety and other considerations, please) if that is what it takes to get the shot. Putting yourself out there is often the difference between an impactful image and one that falls dead. Often, photographers will put their models through amazing feats to get the shot, but wouldn't think of doing similar gymnastics themselves!
These images were all taken with me laying on the ground. In the balloon shot, I was actually on the ground, flat on my back.
The Effect of Focal Length
Composition of the subject within the frame is just one component of perspective to consider. Another powerful tool is focal length selection. Focal length selection can have a dramatic effect on the final image. Not only does it have a marked effect on DOF, but it allows you to compress or expand the background. Moving to a longer focal length, you'll find that you can be more selective of the background whereas a wide-angle lens will show all, making it harder to eliminate distracting background elements.
Focal length also has an effect on the feel of the image. Short focal length lenses from about 24mm (35mm full-frame reference) and down will begin to distort the image, bending straight lines in a fisheye manner, especially at the edges of the frame. This can be very appealing in certain instances, such as architectural photography and certain scenics. Combined with a high DOF (small aperture), imagery with these lenses can take on a real different feel.
This image was taken with a 24-70mm zoom lens at 24mm. The wide angle and high aperture accentuates the leg and provides an element to draw the viewer into the image.
Of course, long focal length lenses provide a means to get close without encroaching on your subject, which makes them ideal for wildlife photography. But because these lenses also allow the photographer to compress the background or highlight what would otherwise be almost inconsequential elements of the background, they are often used in on-location portrait work as well. Consider how to render a sunset behind a model on the beach. A wide angle will show a broad range of the horizon, the setting sun being a small part of that horizon; whereas, using a telephoto, the sun can be a second focal point for the image.
This image was taken with a 70-200mm zoom lens at 98mm. The longer focal length allowed me to select a small set of Christmas lights as the background.
Your Asignment
For this lesson, you will shoot and post at least 3 images.
Image 1:
Find a willing (or inanimate) subject and compose a picture demonstrating use of the "rule of thirds".
Images 2 and 3:
Again, with your willing (or unable to do otherwise) subject, shoot images at two different focal lengths. The objective is to observe the effect on the background. Longer focal lengths will compress the background whereas short focal lengths will expand the background. Post a couple shots that dramatically demonstrate this effect.
Monday, January 3, 2011
Lesson 1: Camera Parts and Basic Terminology; A Primer
For my Treasure Quest friends who requested some photo lessons, here goes...
First things first
You must get to know the basic parts of your camera and some common terminology. This isn't the fun and glamorous part of the photographic arts, but it is imperative that we have a common understanding of some basic terms and references or everything else will be difficult.
Disclaimer and Assumptions
Like almost all photo classes, this set of lessons will be built on the assumption that you have a digital Single Lens Reflex (SLR)camera, or at least a camera advanced enough to control aperture and shutter speeds. A typical point-and-shoot will likely not allow you the control that a creative photographer will require. You will also need a tripod. Although a variety of focal length lenses is desired, I will try to avoid a need for specific focal lengths during the program. There will be a couple assignments that explore the use of various focal lengths, but through the communal learning process we'll experience, it won't be necessary for you to go out and buy additional lenses. (I'll just give you the ammunition to use on your significant other to try and persuade your argument for those capital expenses!)
Lens
Obviously, this is the optical part of the camera that focuses the image onto the film/sensor plane. In most of the point and shoot cameras, this is not an interchangeable item. For those more serious about photography, you need a camera with interchangeable lenses. Why? One size does not fit all! We'll get to more on that later.
There are a few important things to know from the start about lenses. The lens is arguably the most important part of the camera. A poor lens will never yield excellent results -- maybe good or mediocre, but not excellent. You're recording the light that passes through the lens. During the process of recording the image, the one and only thing that stands between your sensor and the subject is the glass of the lens (and any filters you may put on the front of it).
Lenses come in various focal lengths, some fixed lengths (primes), and some of variable length (zoom) capability. In 35mm parlance (the old film size reference), a 50mm lens was considered a "normal" lens, rendering scenes generally as seen by the unaided eye. Longer focal length lenses (telephotos) add magnification for rendering more distant objects with greater detail and shorter focal length lenses (wide-angle) allow compression of a broader cone of vision into the rendered image. There are macro lenses that allow close up photography, micro lenses for really close up photography, and a variety of specialty lenses for special instances, such as tilt-shift lenses. We'll discuss all these in later sessions.
You've maybe heard the term "fast lens". How can a lens have a speed? This reference is to the maximum aperture of the lens -- the ability of the lens to transmit light. A "fast lens" is one that allows more light to pass through resulting in a faster (shorter) shutter speed under the same conditions as a "not so fast lens". Sounds like mumbo jumbo, but this is key to future lessons. This leads us to a discussion of apertures and f-numbers, f-stops, etc. We'll address filters later.
Aperture/F-number/F-stop
In photography, the lens aperture is typically specified as an f-number. An f-number is the ratio of the focal length to the effective aperture diameter -- that's not too important in application so don't get overly concerned over the discussion to follow. In application, much of this will become far more clear.
Lenses typically have a series of marked/indexed f-numbers, or "f-stops". One f-stop is defined as the square root of 2 change in f-number (e.g., going from f2.8 to f4 is one f-stop difference) and happens to correspond to a 50% reduction in transmitted light. If a lens has a maximum aperture (f number) of 2.8, when the lens diaphragm (the light controlling function of the lens) is wide open, the amount of light transmitted would be twice that of a lens with a maximum aperture of 4. What's important in application is understanding that a smaller number means more light coming through the lens, allowing for faster shutter speeds. We'll come back to this principle in your first assignment towards the end of this lesson. This will also be an area we will return to again and again throughout this "course". Just note that the diaphragm within the lens is generally held wide open to allow the most light for focusing and viewing and must spring to it's set f-stop prior to the shutters firing to record the image.
Depth of Field (DOF)
The depth of field in an image is a descriptor of the range of distance in front of and behind the plane of focus that still yields acceptable resolution/focus. An image with a shallow depth of field is characterized by a very narrow plane of focus, objects in the image just in front of or behind the focal plane appear soft or blurry. An image with a high DOF is characterized by a very broad plane of focus with little of the image being soft or blurry. DOF is dependent on both the magnification of the lens and the aperture. Small apertures (high f-stops) yield increasing DOF, whereas open apertures result in increasingly shallow DOF. Larger magnification lenses result in lower DOF at the same aperture than do low magnification lenses.
Mirror
On an interchangeable lens SLR camera, there is a mirror that diverts the imaged light passing through the lens up through a prism (to invert it so things appear right-side-up) and onto the focusing screen that is viewed through the viewfinder. When the shutter release is pressed, the tell-tale click is in part, the mirror slapping up and out of the way of the light just before the shutters fire. You've probably heard tell of "mirror-slap" -- the vibration that results from this movement -- causing image degradation. For this reason, most higher-end SLRs will have a mirror lock-up feature that enables locking the mirror up prior to taking the exposure. We'll explore this further at a later time.
Shutters
Yes, I said "shutters". The modern camera generally has two shutters unlike the single shutter cameras of old. These focal plane shutters (I'm not going to discuss leaf shutters) are the timing device that controls the time the image sensor (or film) effectively sees the light passing through the lens.
In their starting positions, the first shutter is closed, like the curtain before the play begins. The second is actually open. In a long exposure (greater than about 1/200th of a second), the first shutter opens -- for simplicity, let's assume it opens by lifting upward -- and after fully opening and the set exposure timing reached, the second shutter closes -- also by moving upward -- to again block the incoming light.
The timing here is important. As I noted, for long exposures, the first shutter opens and then the second shutter closes. For short exposures, the second shutter follows the first, traveling at the same speed as the first, but before the first ever fully opens. As a result, the sensor/film sees a traveling slit of light and the duration of which any section of the sensor/film sees the light is the set shutter speed, which may be less than 1/64,000th of a second! The shortest shutter speed at which the full sensor is fully exposed between the first shutter opening and the second shutter closing is called the "sync speed" of the camera. This gets important when we start to discuss flash photography.
Sensor/film, ISO and ASA
In the old days, cameras relied on film to record the image. Various films had different sensitivities to light. Slow films had a low ASA/ISO number, fast films, a higher number -- you can look up the definitions if you like, but they aren't too satisfying and not too important, really. Slower films had an advantage of fine grain resolution, ergo better detail recording ability. Faster films where characterized as grainy. The trade-off was in the amount of light required to capture the image. Faster films meant motion-stopping shutter speeds even in low light, whereas slower films meant longer exposure times.
The modern digital camera still has a sensor sensitivity setting and to a lesser degree, high ISO settings result in grainier images but for far different reasons. The important thing to know is that changing the ISO setting of your digital camera by a factor of two (e.g., from 100 to 200) results in a one f-stop change in light sensitivity. (Consider this: a scene is properly rendered into an image at an f-stop of 4, shutter speed of 1/250th of a second, and ISO of 200, to change the f-stop to 8 and keep the same shutter speed, one must change the ISO setting to 400.)
Metering
One can spend an eternity discussing metering and various metering modes of cameras and other devices, but for now, consider the basics. Most things in this world, taken in aggregate, reflect about 18% of the light incident on them. In black and white terms, this means they are gray. Cameras generally use this principal in metering a scene. We'll discuss this further in later sessions. For now, read your camera manual to learn about the metering options and how to control them. We'll discuss some tricks of the trade for metering later.
White Balance
Digital SLRs have a function called white balance. Simply speaking, this is a way to adjust the tonality of the picture to record the scene properly regardless of the lighting situation. You may have noticed that not all light sources produce the same spectrum of light, i.e, they are of different colors. The color spectrum of light produced by the sun is very different than that of an incandescent bulb. Adjusting the white balance allows for the photographer to correct for the different color spectrum when taking the picture. A whole lot easier than making the corrections in image editing software later! We'll discuss the principals of making this correction at a later time.
Tripod
I think everyone knows what a tripod is. Get one -- enough said.
Flash/Strobes/Hot Shoe/PC-sync
Everyone likewise probably knows what a flash or strobe is. This is another areas we could spend sessions discussing, and we will spend some significant time in this arena. Some of your cameras will have built-in flash/strobes. Hopefully, they will also have a sync connection for external strobes. Often, this will take the form of a "Hot Shoe", that place on the top of most SLRs that accepts a portable flash with one to five electrical connectors. In some cameras, they may also have a PC-sync terminal to allow connection of a sync cord for flash. If your camera has neither of these, we'll discuss what you can do to adapt to enable off-camera lighting. In general, we'll discuss the flexibility that artificial lighting provides and the many ways to modify light. Much more on this to come.
Enough rambling! Since a picture is worth a thousand words, I want you to do a simple assignment.
Assignment 1
What you will need:
Objectives:
Steps:
First things first
You must get to know the basic parts of your camera and some common terminology. This isn't the fun and glamorous part of the photographic arts, but it is imperative that we have a common understanding of some basic terms and references or everything else will be difficult.
Disclaimer and Assumptions
Like almost all photo classes, this set of lessons will be built on the assumption that you have a digital Single Lens Reflex (SLR)camera, or at least a camera advanced enough to control aperture and shutter speeds. A typical point-and-shoot will likely not allow you the control that a creative photographer will require. You will also need a tripod. Although a variety of focal length lenses is desired, I will try to avoid a need for specific focal lengths during the program. There will be a couple assignments that explore the use of various focal lengths, but through the communal learning process we'll experience, it won't be necessary for you to go out and buy additional lenses. (I'll just give you the ammunition to use on your significant other to try and persuade your argument for those capital expenses!)
Lens
Obviously, this is the optical part of the camera that focuses the image onto the film/sensor plane. In most of the point and shoot cameras, this is not an interchangeable item. For those more serious about photography, you need a camera with interchangeable lenses. Why? One size does not fit all! We'll get to more on that later.
There are a few important things to know from the start about lenses. The lens is arguably the most important part of the camera. A poor lens will never yield excellent results -- maybe good or mediocre, but not excellent. You're recording the light that passes through the lens. During the process of recording the image, the one and only thing that stands between your sensor and the subject is the glass of the lens (and any filters you may put on the front of it).
Lenses come in various focal lengths, some fixed lengths (primes), and some of variable length (zoom) capability. In 35mm parlance (the old film size reference), a 50mm lens was considered a "normal" lens, rendering scenes generally as seen by the unaided eye. Longer focal length lenses (telephotos) add magnification for rendering more distant objects with greater detail and shorter focal length lenses (wide-angle) allow compression of a broader cone of vision into the rendered image. There are macro lenses that allow close up photography, micro lenses for really close up photography, and a variety of specialty lenses for special instances, such as tilt-shift lenses. We'll discuss all these in later sessions.
You've maybe heard the term "fast lens". How can a lens have a speed? This reference is to the maximum aperture of the lens -- the ability of the lens to transmit light. A "fast lens" is one that allows more light to pass through resulting in a faster (shorter) shutter speed under the same conditions as a "not so fast lens". Sounds like mumbo jumbo, but this is key to future lessons. This leads us to a discussion of apertures and f-numbers, f-stops, etc. We'll address filters later.
Aperture/F-number/F-stop
In photography, the lens aperture is typically specified as an f-number. An f-number is the ratio of the focal length to the effective aperture diameter -- that's not too important in application so don't get overly concerned over the discussion to follow. In application, much of this will become far more clear.
Lenses typically have a series of marked/indexed f-numbers, or "f-stops". One f-stop is defined as the square root of 2 change in f-number (e.g., going from f2.8 to f4 is one f-stop difference) and happens to correspond to a 50% reduction in transmitted light. If a lens has a maximum aperture (f number) of 2.8, when the lens diaphragm (the light controlling function of the lens) is wide open, the amount of light transmitted would be twice that of a lens with a maximum aperture of 4. What's important in application is understanding that a smaller number means more light coming through the lens, allowing for faster shutter speeds. We'll come back to this principle in your first assignment towards the end of this lesson. This will also be an area we will return to again and again throughout this "course". Just note that the diaphragm within the lens is generally held wide open to allow the most light for focusing and viewing and must spring to it's set f-stop prior to the shutters firing to record the image.
Depth of Field (DOF)
The depth of field in an image is a descriptor of the range of distance in front of and behind the plane of focus that still yields acceptable resolution/focus. An image with a shallow depth of field is characterized by a very narrow plane of focus, objects in the image just in front of or behind the focal plane appear soft or blurry. An image with a high DOF is characterized by a very broad plane of focus with little of the image being soft or blurry. DOF is dependent on both the magnification of the lens and the aperture. Small apertures (high f-stops) yield increasing DOF, whereas open apertures result in increasingly shallow DOF. Larger magnification lenses result in lower DOF at the same aperture than do low magnification lenses.
Mirror
On an interchangeable lens SLR camera, there is a mirror that diverts the imaged light passing through the lens up through a prism (to invert it so things appear right-side-up) and onto the focusing screen that is viewed through the viewfinder. When the shutter release is pressed, the tell-tale click is in part, the mirror slapping up and out of the way of the light just before the shutters fire. You've probably heard tell of "mirror-slap" -- the vibration that results from this movement -- causing image degradation. For this reason, most higher-end SLRs will have a mirror lock-up feature that enables locking the mirror up prior to taking the exposure. We'll explore this further at a later time.
Shutters
Yes, I said "shutters". The modern camera generally has two shutters unlike the single shutter cameras of old. These focal plane shutters (I'm not going to discuss leaf shutters) are the timing device that controls the time the image sensor (or film) effectively sees the light passing through the lens.
In their starting positions, the first shutter is closed, like the curtain before the play begins. The second is actually open. In a long exposure (greater than about 1/200th of a second), the first shutter opens -- for simplicity, let's assume it opens by lifting upward -- and after fully opening and the set exposure timing reached, the second shutter closes -- also by moving upward -- to again block the incoming light.
The timing here is important. As I noted, for long exposures, the first shutter opens and then the second shutter closes. For short exposures, the second shutter follows the first, traveling at the same speed as the first, but before the first ever fully opens. As a result, the sensor/film sees a traveling slit of light and the duration of which any section of the sensor/film sees the light is the set shutter speed, which may be less than 1/64,000th of a second! The shortest shutter speed at which the full sensor is fully exposed between the first shutter opening and the second shutter closing is called the "sync speed" of the camera. This gets important when we start to discuss flash photography.
Sensor/film, ISO and ASA
In the old days, cameras relied on film to record the image. Various films had different sensitivities to light. Slow films had a low ASA/ISO number, fast films, a higher number -- you can look up the definitions if you like, but they aren't too satisfying and not too important, really. Slower films had an advantage of fine grain resolution, ergo better detail recording ability. Faster films where characterized as grainy. The trade-off was in the amount of light required to capture the image. Faster films meant motion-stopping shutter speeds even in low light, whereas slower films meant longer exposure times.
The modern digital camera still has a sensor sensitivity setting and to a lesser degree, high ISO settings result in grainier images but for far different reasons. The important thing to know is that changing the ISO setting of your digital camera by a factor of two (e.g., from 100 to 200) results in a one f-stop change in light sensitivity. (Consider this: a scene is properly rendered into an image at an f-stop of 4, shutter speed of 1/250th of a second, and ISO of 200, to change the f-stop to 8 and keep the same shutter speed, one must change the ISO setting to 400.)
Metering
One can spend an eternity discussing metering and various metering modes of cameras and other devices, but for now, consider the basics. Most things in this world, taken in aggregate, reflect about 18% of the light incident on them. In black and white terms, this means they are gray. Cameras generally use this principal in metering a scene. We'll discuss this further in later sessions. For now, read your camera manual to learn about the metering options and how to control them. We'll discuss some tricks of the trade for metering later.
White Balance
Digital SLRs have a function called white balance. Simply speaking, this is a way to adjust the tonality of the picture to record the scene properly regardless of the lighting situation. You may have noticed that not all light sources produce the same spectrum of light, i.e, they are of different colors. The color spectrum of light produced by the sun is very different than that of an incandescent bulb. Adjusting the white balance allows for the photographer to correct for the different color spectrum when taking the picture. A whole lot easier than making the corrections in image editing software later! We'll discuss the principals of making this correction at a later time.
Tripod
I think everyone knows what a tripod is. Get one -- enough said.
Flash/Strobes/Hot Shoe/PC-sync
Everyone likewise probably knows what a flash or strobe is. This is another areas we could spend sessions discussing, and we will spend some significant time in this arena. Some of your cameras will have built-in flash/strobes. Hopefully, they will also have a sync connection for external strobes. Often, this will take the form of a "Hot Shoe", that place on the top of most SLRs that accepts a portable flash with one to five electrical connectors. In some cameras, they may also have a PC-sync terminal to allow connection of a sync cord for flash. If your camera has neither of these, we'll discuss what you can do to adapt to enable off-camera lighting. In general, we'll discuss the flexibility that artificial lighting provides and the many ways to modify light. Much more on this to come.
Enough rambling! Since a picture is worth a thousand words, I want you to do a simple assignment.
Assignment 1
What you will need:
- Camera
- Lens
- Tripod (or a sturdy place to brace your camera for consistent images capturing the same scene repeatedly)
- Your camera manual
- Stationary 3-dimensional subject to photograph
- Constant ambient light (no flash except for steps 3 and 4, if desired)
- Creativity
Objectives:
- To force you to learn how to adjust your camera basic settings of aperture, shutter speed, and ISO.
- To make you aware of how these three settings inter-relate to produce an image.
- To begin to explore the effect of different apertures on the Depth of Field (DOF), that range of distance from the lens either in front of or behind the focal point that maintains focus within the image.
- To get you started experimenting with the basics of photography.
Steps:
- With your camera in a set position, focus on a specific point of the object and take a picture with your widest open aperture (smallest f-stop), noting the shutter speed, aperture, and ISO settings. This will be your reference picture. You may have to dig through the manual for your camera to find out how to discover the various settings and controls.
- Adjust your f-stop by closing it down two (or more) full stops. You will have to increase your shutter speed by a factor of 4 (or more), or increase your ISO by a factor of 4 (or more) to accomplish this. With everything else the same -- same focal length, focusing on the same point, and from the same location -- take your second picture. Compare it with the reference photo from step 1. What is difference? You should observe a difference in the DOF.
- Compose a photo exemplifying an aesthetic use of shallow depth of field (open aperture).
- Compose a photo exemplifying an aesthetic use of deep depth of field (closed down aperture).
- Share photos from 3 and 4 on the Lesson 1 thread on TQ.
(NOTE: Take a look at the distance scale on your lens(es). On either side of the index mark, you may see one or more index lines, possibly with f-stop numbers like "32" or "8" associated with them. These are not as common in modern auto-focus camera lenses as they were in their manual focus predecessors. There used to be a full series of markings for various f-strops to each side of the index line.
A typical DOF scale from an old manual focus lens
A typical DOF scale from an old manual focus lens
This was a tool for the photographer to use in determining the DOF. A photographer would focus to the closest point in the image that he desired to have acceptably in focus, then to the farthest, each time noting where these points lit in the range scale. Then the photographer would set the focus about 1/3 of the way from the nearest point to the farthest and set the aperture appropriately to yield the desired result. Today, many cameras come with a DOF preview button. Pushing the button will step down the lens aperture to the selected setting allowing you to preview the image as it will be rendered to the sensor instead of at the normal wide-open aperture setting. In some systems, like the Canon EOS line, this button will also fire strobes in a sustained burst -- actually a series of very short high frequency bursts -- to increase the lighting for this operation. If your camera has a DOF preview button, learn how to use it.)
An example image with a shallow DOF
An example of an image with a deep or high/large DOF
Saturday, January 1, 2011
A walk in the snow
We finally got some snow, so out with the camera go I. Fighting bitter cold (sub zero temps, 30 mph winds) and wading in knee deep snow, the numbing cold tests my reserve as I strip my gloves to work the cold steel controls of my camera; I stalk the "essence of cold" amid the Jemez Mountains of Northern New Mexico. Thank goodness for the miracle thermal fabrics of today, providing warmth in an unforgiving environment as I practice my art.
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