Chapter One: The Camera
The digital camera has its roots in traditional cameras, so an introduction to traditional and modern camera technology can help us begin to more fully understand the potential of our camera.
The digital camera has its roots in traditional cameras, so an introduction to traditional and modern camera technology can help us begin to more fully understand the potential of our camera.
The digital camera has its roots in traditional cameras, so an introduction to traditional and modern camera technology can help us begin to more fully understand the potential of our camera.
Composition involves creatively manipulating your relationship with your scene and subject to create a more effective expression in your image. Composition involves making decisions about: How much will be in focus? Which subject will be in the foreground? Which lens will work best with your subject? Where should you place the horizon? How close should you be to your subject?
The Digital camera is a wonderful eletronic device that has answered the long time desire to create instant images. These devices use technology much like traditional video cameras, but have much higher resolution capacity and, because of the number of "pixels" captured, now can surpass the ability of film to reproduce what we see.
Another aspect of the digital camera is its nature of being a computer and its close connection to the computer. With the idea of "digital" images comes the idea of enhancing and otherwise digitally manipulating these images so that they look better, sharper, and are more meaningful.
What's more, digital cameras give us immediate feedback about how good our image is that we just captured of the scene before us. This means that we can judge the quality and success of the image taking process while we are still within the process! You can "preview" your digital images and easily make judgements about whether or not to reshoot the image in a different way. This, of course, was always the disadvantage of film...not knowing if the shot you just made will meet your expectations
Digtal cameras fall roughly into 3 types: mini/automatic, compact/full-features, and SLR (Single Lens Reflex) or professional models.
These camras tend to be very small, and are set up to be used primarily on the fully automatic setting. Most however, give you control over exposure through what is called exposure compensation. These cameras have a non-removable lens which generally extends into place when the camera is power on. These cameras also include many special features such as: flash modes, movies, special effects, macro shooting, standard zoom range, and more.
Compact/ Full-featured: These cameras are generally somewhat larger than the mini camera designs, often with an extended zoom range. Some have the capability to support an external flash. MOst give full control over exposure and generally offer a few different exposure modes:
P - Program -this is a fully automatic mode
A - Aperture Priority This mode will give greater priority (allow you to control it) to the aperture when automatically choosing the exposure setting.
S - Shutter Priority This mode will give great priority (allow you to control it) to the shutter when automatically choosing the exposure setting.
M - Manual Full manual control of the exposure
Some of these cameras even offer manual focus, white balance, and other advanced features.
These cameras also generally have most of the features of the mini type of camera such as movies, sounds, special effects, etc.
A new type of digital camera has created a good deal of buzz; the rangefinder. This type of camera actually represents the very first style of 35mm camera in history, but it is a pretty new development for digital cameras. The camera is compact, is NOT an SLR, but has interchangeable lenses. For professionals, the rangefinder has often been the best comprimize between size and capabilities.
SLR: Single Lens Reflex
SLR: SLR stands for Single Lens Reflex. Reflex cameras generally use a mirror to allow you to see through the same lens that will produce the recorded image. The mirror flips out of the way the instant that you make the exposure. The advantage of this is that you'll see through the view finder exactly what the camera will see. Another feature of these cameras is that the lens itself is detachable and there are many lens options. Because of the lens options, these cameras are often better at producing images that exhibit a "shallow Depth of Field". This creates images where the background and foreground are blurry or out of focus. SLR cameras also generally allow you to shoot a series of quick exposures to capture fast action.
The camera body is in essence a light-tight box holding a light sensitive device. It has three mechanisms that allow it to control how it allows light to enter the camera box and expose an image onto the sensor.
One mechanism, called the shutter, controls the length of time the light will be allowed to enter the camera. The shutter basically opens and closes in an instant. The time it allows light to enter the camera between when it opens, and when it closes, is called the shutter speed.
Another mechanism in the camera that controls exposure is called the aperture. The aperture is an opening that can be adjusted to allow more or less light into the camera. Obviously, a larger aperture opening will create more exposure of light to the sensor, while a smaller opening will create less exposure.
The light that that enters the camera is transmitted through a lens which focuses the light to create a sharp image. Lenses are composed of a series of glass elements that are designed to capture a specific angle of view. There are wide angle lenses and narrow angle lenses called "telephoto" lenses (think telescope). There are also lenses that can change their angle of view (or focal length), these are called "zoom" lenses. Zoom lenses are variable-focal length lenses and are not to be confused with telephoto lenses. Some zoom lenses offer only variations of wide angle focal lengths, while most zoom lenses offer variations of telephoto focal lengths.
If you imagine yourself peering through a hole in a neighbor's fence to see what dog is barking on the other side, you can begin to understand focal length. When you put your eye right next to the hole in the fence, you would see the entire yard on the other side, but if you move your eye away from the fence, you'll see less of the other side. As you move away, you'll get a narrower and narrower angle of view. So one aspect of focal length is simply how affects the angle of view. Another aspect of focal length is how it magnifies distant subjects, and how it can distort the relative proportions and distance between subjects.
Telephoto lense are lenses with a long focal length. If you think of using a telescope, you obviously can visualize how it can magnify distant objects so you can see them closer. Another more subtle characteristic of this magnification is the compression of space between subjects, so that distant trees and nearer trees may look surprisingly close together. Telephoto lenses are often used for sports, wildlife, and other subjects that require you to capture a subject that you cannot otherwise approach more closely. Another aspect about telephoto lenses, that we'll discuss later, is that they tend to create an image where the background (behind your subject), and the foreground (in front of your subject) are blurry, while your subject is sharp.
Wide Angle Lenses
Short focal length lenses do pretty much the opposite as long focal lenth lenses. They offer a wider angle of view. They make distant subjects seem smaller instead of magnified, they stretch the relative distance between subjects, and they easily get everything in focus. Another aspect of wide angle lenses, especially when used at a close distance, is optical distortion. If you are very close to a subject with a wide angle lens, the proportions between close and farther away subjects will be distorted and exaggerated. This can even be true with different sections of the same subject. For instance, if you shoot a portrait with a wide angle lens very close to the person, their nose will seem larger than normal, and the ears will seem smaller than normal; creating a strange distortion of their features. Beause of this, wide angle lenses are most often used for landscapes, archetectural photography; not portraits.
Digital cameras have automated features that are intended to make photography easier. Features such as auto exposure, auto focus, auto white balance, auto face recognition, even automatic special effects that can be added during or after shooting.
The exposure setting by your camera when you create an image in a particular lighting, has the most effect on the look and quality of your image. Most capable digital cameras such as the SLR camera, or full featured compact camera, have four basic exposure modes. "Green Box", or "Green AUTO" is the fully automatic exposure mode. "P" is a mode that is automated, but still gives you some control over more advanced settings. "A" is the aperture priority mode, which means that the camera will accomodate the aperture you have chosen manually. "S" is the shutter priority mode, which means the camera will accomodate the shutter speed you have chosen manually. "M" is a full manual mode that will require you to manually adjust both the aperture and the shutter to achieve the correct exposure on your own.
The camera focuses itself by operating a tiny motor in the lens that moves the lens elements back and forth until it maximizes the appearance of contrast between what it estimates is the most contrasty part of your scene. This means that the focus can fail for a couple of reasons: if you scene has very little or no contrast (i.e. pointing at the clear blue sky), or if it "locks" onto a contrasty subject in your scene that was not the subject you intended.
Your camera was desgned to utilize the auto focus capabilities of your lens. Using your camera on manual focus is not well supported, even on the most professional cameras. This is because the viewfinder screen inside your camera is lacking indicators most commonly installed on old manual focus SLRs that help you evaluate the sharpness of your subject while manual focusing.
A new feature of some cameras, is its ability to couple a face recognition algorythm with the auto-focus process, so that it is less likely to focus on the wrong thing when shooting a portrait.
I remember in the 80s when operating a video camera, you had to manually set the "white balance" of the camera to match the lighting you were shooting in. You did this by holding a white piece of paper in front of the camera and then pushing a button called "white balance". When you did this, the camera re-calibrated each of the 3 sensors (red, green, blue) to render the paper white, even if your were in light that was an unusual color, such as incandescent lightbulbs.
The default white balance setting for your camera is AWB, or auto white balance. This means that it automatically recalibrates for the color of your scene with every shot. This can be handy, and tricky at the same time. When it evaluates your scene, if your scene is average mixture of colors, then it's evaluation of your scene correctly estimates the color of the lighting, but if your scene is predominantly one color, it can cause it to shift the color away from your subject and negatively affect your color balance.
For these scenes, you may want to use one of the manual white balance settings that most closely matches the lighting in your scene. The most common manual white balance settings are: Sunlilght, Cloudy, Open Shade, Light bulb, florescent light.
First, push the button halfway
The first step I take when I see something I want to photograph is evaluate the lighting, but more on that later. The next step, is always to look through the frame and position my subject right in the middle, then push the exposure button half-way down. Pushing the exposure button half-way down will invoke the camera to do all the operations it does when you shoot a photo except for actually exposing the sensor: Auto focus, auto exposure, auto white balance. In fact, when your camera confirms focus on something it should make a sound and even illuminate a box inside the viewfinder that shows you what it has focused on. If it has focused on the wrong thing, you can let go of the button, and try again.
All these operations take a little bit of time, especially the focusing. This means that if you just simply push the exposure button down without first confirming focus, you will most likely experience a delay before it actually takes the shot.
Digital cameras offer the amazing opportunity to immediately inspect a photograph that you have captured, and I strongly suggest you get into the habit of quickly looking at your camera's screen once you hear the shutter, and evaluate your image each time you shoot. When you're shooting an image you are in "Capture Mode", but you can also preview your image for an extended time by finding the "play" button generally near the screen on the back of the camera which gets you into "Preview Mode". While you are using "Preview Mode", you can even magnify parts of the image to inspect details up close such as faces, shadows, etc. Once you're done looking and want to shoot another photo, you can usually simply touch the exposure button and it will switch back to capture mode.
There are a few camera accessories I strongly recommend, and many that are so specialized, you will likely not need them right away.
I strongly suggest having a tripod of some sort with you when you can. It is important to remember, that although your camera has many shutter speeds to choose from, you can only use the fast ones without a tripod with which to hold the camera steady. Tripods can range from small, light, and cheap; to heavy and expensive; and everything in between. One guideline I would consider is that it need only be as sturdy as your camera requires; if you have a light camera, you may only need a light (and cheap) tripod. If you have a heavier camera, you will need a heavier and more expensive tripod. Some of the newer carbon-fiber tripods offer the best of both worlds (light and sturdy), but with a heavier cost.
For those of you who have a "hot shoe", or "accessory shoe" on top of your camera, you have an amazing opportunity to take advantage of the option of attaching a secondary light source to your camera. An external flash attachment can not only offer you much more power and capability of adding light to your scene (even in bright sun), but can also (generally) allow you to point the light away from your subject and "bounce" it off a wall or a ceiling. This "bounce flash" technique can help you create dramatic lighting by experimenting with the direction and quality of the light from your flash, instead of just having it point directly at your subject light a "deer in headlights".
A lens hood attaches to the from of your lens like blinders to keep light from entering the lens at such an oblique angle that it simply lights up the inside of the lens and causes "lens flares" or bright spots on your image. Often after-market hoods can be purchased from a fraction of the cost of manufacturer brand hoods.
More on this later, but many options exist for pieces of colored glash that can be attached to the front of your lens which affect your image.
The creation of a photographic image as the result of exposure to light, is just like the result of a "photo-chemical" reaction. To make this easier to understand, consider photo-chemical reaction that is familiar: a sunburn. A sunburn happens when your skin gets too much exposure to sunlight. Exposure can be better understood if we consider what conditions come about to make a sunburn happen. For instance, you might get a sunburn if you:
These three variables are present in any photochemical reaction:
Sensitivity = How readily does the chemical react to light and how fast the reaction takes place
Amount = How much light is the chemical exposed to
Duration = How long is the chemical exposed to light
For instance, you may also be sunburned if:
In this above case, the additional exposure time may be required to compensate for the medium skin that doesn't react has quickly to the light
In this case, the additional exposure time compensates for the indirect sunlight
This last example may not actually result in a sunburn, but the concept is what's important. in your camera, the same conditions can be manipulated through camera settings:
Sensitivity: The "ISO" controls how sensitive the camera is to light and increasing it can help you shoot more effectively in low light conditions
Amount: The "Aperture" controls how much light enters the camera
Duration: The Shutter controls the duration of exposure to light or the "exposure time"
Proper exposure is curcial, without it you won't get an image--too much or too little exposure is the main reason for digital images to come out poorly or not at all.
Proper exposure is established by the camera through the use of a light meter and a certain combination of mechanical settings which control the amount of light that reaches the sensor. These are known as the Shutter and the Aperture.
The camera is mainly a box that holds the light sensitive sensor. It also has a lens that focuses light onto the sensor. The most crucial part of taking a photograph is controlling how much light reaches the sensor so that it will in fact create an image. The camera has two devices that control the “exposure” of the snesor:
The shutter in the camera can be manipulated to allow the light to reach the sensor for only a split second, or many seconds long. The most common shutter speeds are fractions of a second such as 1/60th of a second or faster; up to 2000/th of a second on average. These fractions of a second are denoted on your camera simply with denomenator. (i.e. 1/60th, as simply 60).
The aperture in the lens can control how much light reaches the shutter. It works in the same basic way that the Iris does in our eyes. By constricting the aperture to a small hole, the lens will only allow a fraction of the light that it normally does. The normal aperture settings correspond to exactly half or twice as much light as the previous setting.
Other reasons to use fast/slow shutter speeds
Because the shutter can reduce your exposure “time” to a fraction of a second, it can be used to “freeze” action such as sports events or moving water. The shutter can also be used at slow settings (long shutter openings, or long exposure times) to allow you to shoot in dim lighting, and to allow you to blur your subject if you want--such as the “milky” rivers in some landscapes. This bluring action happens when the movement of the subject takes place at a faster pace than the shutter speed. The rule of thumb is: don’t try to shoot a photo holding the camera at a speed slower than 1/60th of a second, or you’ll get camera movement and your entire photo will be blurry. For slow speeds it is recommended that you use a tripod to avoid such camera movement.
The aperture can reduce or increase the amount of light that actually gets through the lens, but it can also effect your picture’s focus. When you look through your camera, you are generally looking through it at its widest aperture (so that you get a bright view of your scene). When you push the exposure button, the camera will quickly constrict the aperture to whatever setting the camera is on.
Large apertures (like the one that you see when you look through the viewfinder) represent the world a lot like we do with our eyes; whatever the lens is focused on will be sharply focused, but the background and foreground will be blurry. This is generally referred to as a “shallow depth of field”, or “depth of focus”. Small apertures on the other hand, when the aperture is constricted to a very small opening, have the effect on the appearance of the image that is referred to as “large depth of field”. It will give the appearance of having everything in focus; both background and foreground. This is not how we normally see the world and so this aspect of the photographic image is one that is unique. The depth of field of a photograph is a description of how much range of distance
is sharply focused in the image.
You probably have seen how many portraits only have the subject in focus and the background is out of focus. This effect is created with a wide or large aperture and the resulting narrow or shallow depth of field.
Large Depth of Field
In many landscape images, you probably have seen just the opposite, foreground, middleground and background all in sharp focus. This effect is achieved with a small aperture opening and results in a large (deep) depth of field range.
Very often, these landscape photos are shot with a tripod, because the small aperture severely cuts down the amount of light reaching the film, and thereby forces the photographer to use a slow shutter speed to compensate. In the same vein, photographs of fast action often need
to use a wide aperture to compensate for the very short interval of time the fast shutter will allow light to be recorded on the film
Again, most of your decisions when taking a photograph will be about how to capture the scene. If you have a fast subject, you could freeze the action, or blur the action depending on the shutter speed setting you choose. If you have a portrait or a landscape, you can choose to have most everything sharply focused, or have only one subject sharp while the background and foreground are blurry.
To give you the flexibility to easy choose one setting over the other, I suggest you use the "Aperture Priority Mode" which is an automated exposure mode on your camera denoted by "A", or Av". When you choose a specific aperture setting, your camera will automatically accomodate it by choosing a corresponding shutter speed that will provide the right amount of exposure depending on the lighting in the scene. When the camera is automatically setting your shutter, it does so with the help of a mechanism that measures the light called the "light meter".
How does the camera know?
So how does the camera know what is the correct exposure? The light meter in your camera is designed to “see” grey. A certain grey that reflects exactly 18% of the light that hits it. The meter is calibrated for this brightness and so is your sensor. Let’s just say that it is a grey that is exactly in the middle between very bright and very dark. The idea is that the meter will (in most situations) be able to get the right setting by averaging out all the tones in the scene you’re pointing at. In some cases, however, the scene you’re looking at will not be the average scene with equal amounts of black and white. In these cases, the meter may get fooled by the brightness or darkness of the scene and give you the wrong exposure setting. A good example of this is a situation where you have a person sitting in front of a bright window.
When I shot the scene, the camera was fooled into thinking the scene was very bright simply becuase there was so much brightness behind the subject. When this happens, it is because most of the details in the scene were very bright; it did not know that the person in the shot was the most important part of it. So when the light meter suggests a combination of settings to use, its "grey" averaging is skewed by the greater proportion of bright objects in the scene, and causes it to inadvertently under-expose the subject.
To avoid these problems, it is important to remember that the light meter is designed to average out tones, or see grey. It can often be easy to get the proper exposure for difficult lighting situations by re-framing your scene to avoid the bright backgroun; and then "locking-in" this setting before you shoot with the original composition. By doing this, you will help the camera avoid the bright background and thereby allow it to give you the proper exposure for your subject only.
What I needed to do was to "skew" the average, or in other words control the averaging process so that it will give more exposure to the person. I decided to point the camera so that half (or a little less than half) of the frame was occupied by the bright background, and the other half was occupied by my subject and the darker objects around her. I pressed the exposure/focus button down halfway, so that the camera would adjust the exposure and focus. Then, keeping the button down, I re-framed back to my original composition. Keep in mind that I didn't use the flash. If the flash is on, the camera will not adjust its exposure. This resulted in a bright background that was a little over-exposed but also resulted in better tonalities and details in my subject.
Remember: Above average brightness will give below average exposure.
Exercise: 1 Easy Auto Exposure Compensation
Slow Shutter and Small Aperture
In this case, a slow shutter speed was used purposely to blur the moving river water. The photographer did this with a slow shutter of course, but also by choosing a dimly lit scene, and by using a small aperture which in effect forced the use of the slow shutter (because it so severly cut down the amout of light entering the lens).
There are other ways to compensate exposure that can sometimes be more practical. You may have noticed, the method mentioned above requires that grey subject which you point at to set your exposure (compensate your exposure) is the same distance away from the camera as your actual subject, otherwise you're likely to get the wrong focus setting. So how can you manually over-expose for a backlight situation when you have no gray subject, or it is difficult to find a grey subject that is at the same distance?
The process is different on different cameras, the concept is basically the same. When your camera is set to Aperture Priority (which is my suggestion for where it should be most of the time), the camera basically makes the call about how to create an image that will be the result of averaging the tones in your scene. For darker scenes (where the tonality of the scene, or especially the subject in the center of the frame is dark), it will give you too much exposure by trying to average to grey. In these cases, you may want to manually compensate the exposure setting to under-expose the scene instead of leaving it to the camera.
ISO is a rating that refers to the "sensitivity" of the sensor. This means it directly affects how much light (or duration of exposure) the sensor will need to get the proper amout of exposure. Sensor settings of 100 ISO are not very sensitive and so require more exposure--for this default setting it is usually recommended that you shoot in bright sunlight.
Sensor settings at 400 ISO are more sensitive, require less exposure and can be used in more dimly lit situations, such as on overcast days, under a forest canopy and indoors.
Another consideration of ISO is that higher ISO settings are achieved by an amplification of the image signal from the sensor and will exhibit more noise or “graniness” and a “sandy” quality to the details. “Slower” ISO settings such as 100 will have less graniness and are therefore often preferred for enlargements. The degree of noise at various ISO settings depends on the manufacturer and the type of sensor. The image above was shot with a Canon SLR that uses a CMOS sensor. This camera is especially adept at rendering good detail at high ISO settings. Other cameras will produce even more noticable noise.
This means, that the best ISO setting is the slowest one that you can use. Again, this is why a tripod is so useful. I generally shoot all my nighttime photographs at ISO 100. This is not because ISO 100 is very capable in low light, but instead it is because I am after the best image quality AND I have a tripod!
The direction from which light is casting onto your subject has a huge impact on the appearance, clarity, color, and mood of your subject and your photograph. The direction of the light is often my first decision in creating a photograph. A single light source (such as the sun) can be coming from various directions:
Top Lighting: When light is coming down on your subject it gives it a certain look, but also if it is natural sunlight, it also has a certain color, contrast ratio, etc. For most shots, it is best to avoid the middle of the day, as the top lighting creates hight contrast, with dark shadows and bright highlights. Here, notice the distracting dark shadows in the face.
Side Lighting: When light is coming from the side, it can give a greater impression of texture and volume, but also creates more of a dramatic impression. Also, when in sunlight, side lighting is generally achieved when the sun is lower to the horizon. This angle can also have an effect on the color of the sunlight due to it travelling through more of the earth's atmosphere. You will notice, that the color of sunlight gets more and more yellow as the sun gets lower to the horizon. Pointing your camera so that you are 90 degrees to the setting sun is the best way to get deep blue skies.
Back Lighting: Backlighting can make it tricky to get the correct exposure, but however can create very exciting effects with shadows, halos, etc. When the sun is low on the horizon, you can actually position the disc of the sun behind objects and watch how the scene changes dramatically.
We have already mentioned how the sunlight itself changes color as the sun gets closer to the horizon, and this may force you to use a manual white balance setting (such as daylight) in order to preserve the light color as an effect.
By the same token, if you are shooting entirely in the shade on a sunny day, what is the light source? The light source isn't the sun because you are in a shadow, so the light source is the blue sky and therefore the light color will be very blue. In this case, you may want to use the manual white balance setting called "open shade". The open shade setting calibrates your sensor for a greater sensitivity to yellow, thereby making your shot more yellow.
On cloudy days, the light is relative bluish too, though not as much as open shade. So the cloudy white balance setting adds a little less yellow than the open shade setting. Sometimes photographys will purposely use the cloudy setting to add a little "warmth" to a photograph.
Artificial lights are even more varied in color, which is why you may have noticed so many of the white balance settings are associated with artificial lights. Manual white balance settings can be thought of in two ways:
With these two approaches in mind, consider the following:
Daylight: Neutral color. Under daylight lighitng, white paper will look white.
Cloudy: Add yellow. Under cloudy sky, this setting will make white paper look white. Under daylight, this setting will make white paper slightly yellow.
Open Shade: Add more yellow. In the full shade of a clear sky, this setting will make white paper look white. Under daylight, this setting will make wite paper look quite yellow.
Incandescent (lightbulb): Add blue. Under incandescent lighting, this setting will make white paper look white. In daylight, this setting will make white paper look blue.
Flourescent: Add magenta. Under flourescent lighting, this setting will make white paper look white. In daylight, this setting will make white paper look magenta.
There are various flash modes in our cameras some are more useful than others, and some are surprisingly useful.
Slow Flash Examples
Some of you have cameras that will accept a separate flash unit. These flash come in many sizes and designs, but the best will allow you to rotate them 360 and angle them up and down. The reason for this is that you can bounce the light from the flash off of ceilings or walls and get a much more natural, soft and diffused light quality than you can ever get with the flash pointing directly at your subject. This is the main downfall with on-camera flash that can only be overcome with a separate flash unit.
The easiest way to use bounce flash is to bounce the flash off the ceiling by pointing it stright up. This will light up the ceiling and create a softer and larger light source from above. This tends to look very natural becuase light from above is what we normally experience indoors and outside.
Another way is to bounce the flash sideways. This can give much more dramatic light quality and can enhance texture.
Either way, it is important to remember that the color of the wall or ceiling you're bouncing off will affect your light color that illuminates your subject, so white walls and ceilings work best, and wood or dark walls and ceilings don't work very well. In the same way, very high celings won't work well either because the amount of light that will bounce back could be so low that you don't get enough expousre.
Low light situations can be the most challenging because cameras don't easily see in low lighting conditions. In order to get enough exposure in a low light situation, you can open your aperture to the largest opening, you can reduce your shutter speed to create a longer exposure time, and you can increase your ISO to make your sensor more sensitve to light; or all of the above.
Large Aperture: Opening the aperture all the way is possibly the best solution unless you have a tripod and a stationary subject. The difficulty here, is that lenses with very large aperture capabilities also require very large lens elements, and therefore tend to be very expensive. Often professionals will pay thousands of dollars more for a lens that is even one extra aperture setting in order to better capture images in low light, not to mention the depth of field possibilities.
Long Exposure Times : For stationary subjects, using a long exposure time and a tripod can allow to capture enough exposure even if you use a small aperture. That means you could get enough exposure and get everything in focus, even in very low light. I often shoot photographs at night and use almost the smallest aperture I have. This allows me to get everything in focus at night, but forces me to use a 30 second exposure time.
ISO : For low light situations where you have to also capture moving subjects (like a rock concert), the ISO is likely your best option. If you have a lens with a very large aperture, use that for sure, but most likely you still may need to adjust your ISO. Increasing the ISO will make your camera more sensitive to light and thereby allowing you to get proper exposure with much less light. Often, higher ISO settings are called "fast" ISO becuase it can allow you to use a faster shutter speed than you otherwise could.
Filters are small pieces of glass you attach to the from of your lens that affect your images. Some of the most useful include:
Polarizing filter: Polarizing filters change your image in may ways
Depth of field, or "Depth of Focus" is a term that describes how much depth ( or spacial distance) is sharply foused in your image. If you have ever looked through binoculars or a telescope, you might remember that the focusing is crucial; only one object at any particular distance will be sharp, and the rest of the image will look blurry. Telescopes and binoculars always look like this, but in your camera, you can creatively control depth of field to help the expression of your photograph.
Three Factors that control depth of field:
To get the blurriest background or foreground, or the most shallow depth of field, you could combine all these factors: Get close, Use a long focal length, open up your apeture.
Aperture Priority Mode
It is important to remember that the aperture is also being used by your camera to control exposure, so all the shooting modes will affect your aperture. However, I suggest the Aperture Priority Mode to give you the easiest control of your aperture, which inturn will give you the easiest control over how much will be in focus. On Canon cameras, this is indicated by Av. On other brands, this is often simply marked by A. When using the aperture priority mode, the camera will automatically choose the shutter speed that suggested by the light meter to give the correct exposure. That means, that as you change the aperture, you should watch that the shutter doesn't dip below 1/60th or so, otherwise, it will likley be too slow for you to hold steady without a tripod.
Moving closer to your subject is sometimes the easiest way to make a better photograph. You should always be considering what else is in your viewfinder that is distracting or doesn't belong. By getting closer to your subject, you can easily begin to eliminate extraneous background objects that are not contributing to your image.
Another thing that happens when you get closer, is that your background may get blurry due to the shallow depth of field that results from being close. Often this is great because it further minimizes distracting background subjects that you couldn't quite eliminate by just getting closer.
Sometimes you want everything in focus, and still capture a sense of depth. The challenge of capturing the sense of space in a scene you're shooting, is that the photograph you are creating is a two dimensional representation of the scene you're currently looking at with two eyes. I suggest closing one eye, and look again at your scene to see if it loses something. At this point the challenge may simply be to move your point of view so that you can precisely arrange the subjects in a configuration that captures that sense of space even in two dimensions. It will also help to attempt to present a foreground subjet (close to you), a middleground subject (farther away), and a backround subject that are all easy to distiguish from one another.
First, arrange subjets so that they don't interfer with each other. Try to give each main subject it's own space apart from other main subjects. It also works best if each main subject is isolated agaist a plain background if possible. Especially in portaits, this means move your angle to the person ( or even the person ) so that there isn't a background object directly behind them that could converge with their form.
If you look at the image to the right, what do you see? We all have an innate sense of how to interpret visual clues about our world. The three lines very likely suggest a scene of a road and a horizon. Although, if you try, you can look again, and see it simply as three lines, or a plane balancing on a point, but the first reaction is more innate. This means that we can more easily suggest a sense of space if we capture in our image a sense of "converging parralell lines" as in the diagram.
Another visual clue about depth and space is the variances between the size of repeating similar objects. When we see a small and a large similar object next to one another, we may assume that it is two different sizes of a similar object; but if we see more than two sizes of a similar object in a photograph or drawing, we will likely innately assume that all the objects are actually supposed to be the same size, but at different distances.
Remember that the focal length of your lens affects both your angle of view, and the apparent relative distance between subjects, and the relative proportions of subjects that are close to you. You can take advantage of this if in the right situation.
Yikes! In the portraits above, a wide angle lens was used very closely to the subject's face. This caused distortion of the face, making the nose look disproportionately large. It is generally better to use a long telephoto lens (setting) for portraits. This helps reduce the size of noses and preserves appealing proportions in the subect's face. It can also help blur any distracting background with the shallow depth of field that comes with using a long lens setting.
Here, I have again tried to keep the foreground subject the same size between the two shots, but notice how it affects the background subjects.You will notice that the wide angle lens exaggerates the relative distance between the subject and its background, while the telephoto lens seems to push the foreground and background closer together. You can also, of course, see how the wide angle lens captures a wider angle of view than the telephoto shot, showing more of the play structure in the background.
From a compositional standpoint, it means that if you are trying to create greater emphasis on a subject relative to other less important objects, getting close with a wide angle lens can help make your main subject relatiely larger and closer than the other objects.
The foreground subject is put off-center according to the rule of thirds.
The photographic frame sub-divided into thirds.
Placing the subjects off-center draws emphasis to the surroundings, and makes this an "environmental portrait".
The rule of thirds guideline for off-center subject placement is the traditional way to create a well-balanced photograph. Placing a subject off-center in this method, can create slight tension and excitement in your composition, rather than static calmness that placing your subject in the center seems to create.
To follow the rule of thirds, imagine that your camera's viewing screen is etched with grid lines, resembling a tic tac toe game. As you view the scene, place the subject along one of these lines, or at one of the intersecting points. Here are a few examples to consider when composing in this manner.
By placing the horizon in your scene at the bottom line of the grid, this will create more emphasis of the sky by devoting 2/3 of the frame to the sky. If the sky isn't that interesting, place the horizon on the top line and instead shift the emphasis to your foreground subject.
In a close-up portrait, for example, place the most important subject element--the closest eye, perhaps--at an intersecting point in the frame. This should be one of the two top points so as to avoid excessive space above the subject.
Move the subject
If you can, move the subject to a more appropriate spot in order to carry out any of the previous suggestions. Otherwise simply move yourself and the camera. That may mean moving to the left a few feet, shooting from ground level, or driving a few miles to a more appropriate vantage point.
Leave space for a moving subject to "travel into"; if it's an animate subject at rest--such as an animal or person--leave space for it to gaze into if it is not looking into the lens.
In any off-center composition with a small center of interest, there will be some empty space in the frame. Compose the image so that there is something of interest, --or a secondary, perhaps more distant subject-- to satisfy the view's eye as it explores the picture. If you want to emphasize isolation, leave the space empty.
At the very least, this "rule" will help you begin to look more closely at the relationship between your subject and the frame around it. Basically, it is a decision you will make to purposely place the subject in a position that makes the image more interesting.