So, you just bought your first DSLR camera and you are interested in joining the ranks of image-makers everywhere who find pleasure and creativity in documenting the world as they see it. What are you gonna do now? Do you know how to set your aperture? Or what ISO is? Did you know that DSLR stands for Digital Single Lens Reflex? It doesn’t matter: what you do know is that you’re ready to step up from your point-and-shoot camera and create images over which you have more control.
A digital SLR camera is a great machine that allows you to shoot in complete auto mode but also allows for manual control of almost all elements of image creation. The advances made in recent years to even entry level DSLRs is amazing, but for me, one advantage goes before all others: it is a great camera on which to learn the basics of photography. That is the place to start, because there is no other. I commend you for your decision, and in this article I will try to spell out a few of the basics of exposure, composition and camera control that will aid you in your self-discovery. First thing though, all modern DSLRs have Auto mode (or Program Mode) in which the camera will do most of the decision-making for you. I encourage you to use that assistance until you are up and running and able to make adjustments that improve your imaging.
Also remember, one of the great advantages of digital photography is that mistakes cost almost nothing. There are no processing and printing charges and you can see the effects of your settings changes almost immediately. A digital camera is a great learning tool and there is no fee incurred to rattle off 36 digital images all with different aperture, shutter speed or white balance settings. Trial and error, it’s the only way to go!
There are three main factors when it comes to properly exposing a shot: aperture, shutter speed and ISO sensitivity, sometimes called “the triangle.” They are intertwined factors, working separately but together to let the proper amount of light into the camera so that your images are not overexposed, which means too much light has entered the camera and your photo is overly bright or even all white, or underexposed, which means your images are too dark to properly see the subject.
Let’s start with aperture, which simply means "opening." In photography, the aperture is the circular opening inside the camera lens that allows light in to strike the film or digital sensor. Controlling the size of that opening is what we call "setting the aperture," and the sizes of the opening are represented by f-stops, such as f/2.8, f/8, f/22 and so on. A smaller f-stop number corresponds to a larger opening. If we go from f/2 to f/2.8 to f/4 to f/5.6 to f/8 we are making the opening smaller and smaller in full-stop increments, each of which allows in half the amount of light as the previous setting.
Because each roll of film or equally calibrated sensor will react in the same way to the amount of light projected on it, the trick to aperture is figuring out how much light should enter the camera for a proper exposure. If it is a very sunny day, you will need to limit the amount of light so as not too overexpose your image, and that would call for closing the opening or “stopping down” the aperture. If, on the contrary, it is relatively dark, you want to open the aperture as much as needed to let in enough light. Here, let me mention that what seems like enough light for our eyes is not always enough for a camera. If you are in your living room at night and can see fine with the lights turned on, that’s not necessarily enough light to properly expose a shot.
Opening and closing the aperture has another effect on how your photo will turn out, and we will talk more about that in a few paragraphs; however, when you open up your aperture wide you are able to focus only on subjects within a small range, a “shallow depth of field.” But with a smaller aperture, you can focus on a deeper amount of space within your image. Let’s say you are looking down a row of cans. With a small aperture (a higher f/number), all of the cans, closest to farthest, should be in sharp focus, but with a wide aperture (f/1.4, let’s say), if you focus on the front can, only that front can will be in focus and the rest will be gradually blurry. Neither one of these approaches is necessarily better it just depends on the look you want. Some people love the dappled, rounded, soft out-of-focus highlights outside the optimal points of sharp focus; it’s referred to as "bokeh," from the Japanese word for haze. The character and feel of bokeh is largely contingent on the lens's optical design and the number of metal blades that create the degree of roundness of the lens aperture.
Now, getting back to how you let light into your camera. We see how a smaller or bigger opening can let in less or more light, but it’s the photographer’s job (or the camera’s on auto) to realize how much light is correct, and that is often a matter of shooting and seeing if it looks right and trying again if it doesn’t. Of course, there are tools to help you figure out what is the proper exposure. Most modern cameras, and certainly the new DSLR you just bought, have internal light meters that will give you their reading on what is the correct amount of light. In the “olden days,” and for photographers who need to be very precise in measuring light, there were and still are hand-held light meters. Light meters vary in terms of their sophistication and in whether they measure light that reflects from a subject, or the general ambient light of a scene, but the bottom line is that they measure the amount of light in your scene. And with that measurement you can set your camera’s aperture accordingly. Whether by experience, a light meter, the camera’s auto exposure function or simple trial and error, knowing how much light to let in, and basing your aperture setting accordingly, is the most basic and important step in photography.
Let’s move on to shutter speed, the second of our three exposure factors. The shutter in a camera is a device that closes (and opens!). With your aperture already set to a certain size, you push the shutter-release button on your camera and the shutter opens and then closes, allowing light to strike the sensor (or film) for a certain length of time. How long that shutter stays open is referred to as shutter speed. Normally, shutter speed is very fast, and although the difference between 1/1000 of a second and 1/30 of a second is hard for us to recognize, in terms of how much light gets into the camera, that fraction of a second is significant and can easily over- or under-expose your image or result in an image with too much motion blur. Most DSLRs offer a shutter speed range between 1/4000 of a second and 30 seconds; however, some extend higher to 1/8000 and many offer what is called "bulb" exposure, with which you can hold a shutter open as long as you like.
Before we talk about the effects of fast or slow shutter speeds, let’s remember that the settings of aperture and shutter speed work hand in hand. If your aperture is open wide, allowing a large amount of light in, you have to set your shutter speed accordingly. For example, if you are shooting on a bright day with an open aperture, you should set a fast shutter speed to make sure that exessive light does not enter the camera and over-expose your image. Conversely, if it is dark and you need as much light as possible, you open up your aperture and allow for a slower shutter speed so that light has more time to enter. It is here that we need to mention the good and bad about shutter speed.
If your shutter speed is slow, and by slow let’s say anything from 1/30 of a second on through whole seconds, then not only will you let in a good deal of light, you will also let in motion, whether it be the motion of your subject or the movement of your own hands. This motion will create a blur that in most cases is not desirable. The idea then is to find a combination of aperture and shutter speed settings that allow enough light into your camera without so much time passing that you ruin your exposure with a shaky hand. It’s a delicate balance, especially when working indoors or in low light. Fortunately, there are ways to compensate for these factors. You can use a tripod or remote control so that the camera remains still, or use highly sensitive ISO settings to compensate. Also, because you purchased a new camera and lens combination, it’s very likely that either the camera or lens features an image stabilization system that uses digital or optical techniques to offset the effect of camera shake. This is a great assistive tool, but it's best not to rely on it too much. Of course, if the situation feels appropriate, you can also add more light to your scene with a flash or other light source, but this often completely changes the nature of your final image.
And remember too, the effects of slow shutter speeds are often very beautiful. Think of how rushing water looks when it blurs over a creek bed or how cool red car lights look as they form long lines in the darkness, or even the blur of countless people passing through a train terminal. Also remember though, the blur in your subject that can express movement can be great, but the blur caused by camera shake is rarely appealing. Earlier I mentioned 1/30 of a second as a slow shutter speed, and that is a general rule of thumb for me. I feel that at 1/30 I can personally keep still enough to grab a shot, sometimes even a little slower, but for others anything below 1/60 and you’re risking blur, especially as the focal length of your lens increases.
There is no pat answer and much depends not only on your own hand, but on the focal length and quality of your lens, the ISO setting and the type and purpose of your image. An often-used rule of thumb is to set the shutter speed to be as fast as or faster than the 1/the focal length of your lens. To obtain optimal sharpness, if you are shooting with a 60mm lens, for example, the slowest shutter speed you would use is 1/60 of a second. If you are shooting with a 250mm lens then the slowest shutter speed to use, handheld, would be about 1/250 of a second, and so on. This is a rule of thumb that applies to cameras with full-frame sensors. If you are using a DSLR with an APS-C-sized or smaller sensor, you will need to increase shutter speed depending on the crop factor of that sensor.
While we’re talking about shutter speed and blur, there is one great effect that a slow shutter speed can get you, and that is the feel of speed in a photo when the subject is sharp and the background is a blur. This can be created by setting the shutter speed to something like 1/15 of a second and panning as you shoot your image. If, for example, a boat is speeding down a river, you start panning (following the subject in your viewfinder) with the boat before it reaches your desired background and shoot as it arrives and then continue panning as it moves out of the frame. The slow shutter speed combined with panning movement should blur the background and if your hand (or better a tripod) is stable when you shoot, the central subject should be in focus and sharp. Of course, this not an exact science, you should be prepared to try again with an adjusted shutter speed or a more stable grip if the shot is not to your liking.
Fast shutter speeds can create very dramatic photos as well, especially when shooting sports or wildlife and you’re able to capture that frozen instant, stopping time at the perfect moment. However, in combination with an open aperture, fast shutter speeds will allow you to take beautiful portraits or close-ups. As I mentioned earlier, a wide-open aperture creates a shallow depth of field in which the foreground is very sharp and the background nicely blurred. Say you’re shooting a close-up portrait in which you want your subject’s eyes to be tack sharp and the rest of the image gradually blurred. If you are shooting in bright daylight or studio lights where an open shutter will allow in too much light, setting a faster shutter speed can allow you to work with that open aperture so that too much light does not overexpose your shot, and still allows for the effect of shallow focus.
ISO sensitivity is the third aspect of exposure. It refers to the light sensitivity of the film or sensor. Back in the day, you would buy film according to its sensitivity and keep that ISO setting until you finished that particular roll of film. With digital sensors, you can adjust ISO sensitivity after each shot if so desired (and modern cameras have expanded the breadth of usable ISO sensitivities immensely). When before, almost everyone shot with film between ISO 100-800 (although higher and lower were available), now it’s not uncommon to see digital sensors that can be set as high as 25600 or even higher. Regardless, whereas before ISO sensitivity was generally a fixed number that you worked around until you changed film, with digital sensors it can be employed more liberally to adjust exposure. For example, if you set ISO to a relatively high 1600, you have made your sensor more sensitive to the light that strikes it through the lens and can therefore capture your image with less available light. This allows you to use faster shutter speeds to capture images without blur. It is particularly effective when shooting in low light or when shooting with very long lenses that let in less light.
The problem with raising the ISO is that more sensitive settings create lower-quality images with more “noise.” Noise can be described as discoloration or graininess in your image, and the higher the ISO, the more noise you will see. At certain levels and with certain types of shots, it may be barely noticeable, but as you enlarge your images that were captured with a high ISO, you will begin to see the noise, and the delineation between objects and colors will not be clear. In some cases and when shooting at night, a high ISO setting will allow you to stop down your aperture a bit or increase your shutter speed to capture a blur-free image, but it’s not a perfect method and certainly, when possible, a photo shot with a lower ISO will be richer and better colored than one shot at a higher ISO. There will be times, however, when your creative impulses will call upon you to set aperture and shutter speed in such a manner that the only way to keep your shot clear will be to up the ISO, and in those cases, you will be happy that your modern digital camera has high-reaching sensitivity.
Bringing It All Together
ISO may have been the last element we discussed, but when you are ready to go on your first shoot, set your ISO first based on the amount of light you will be working with. If it’s a bright sunny day, set it low, between 100-400. Then you can set your aperture and shutter speeds as each shot dictates. And remember, you may need to try a few times for each shot to get the exposure right. Also note that on your camera you will have program auto mode (P), manual mode (M) for total control of settings, aperture priority mode(A or Av) in which you set the aperture and the camera adjusts the shutter speed accordingly, and shutter priority mode (S or Tv) in which you decide the shutter speed and the camera sets the best aperture.
As you get to know your camera you will understand when it's best to use those modes, but as you may still be working in program mode, there is one final exposure setting that can help you nail the perfect shot. It’s called compensation adjustment (Exposure Bracketing) and it’s usually denoted with a +/- button or a dial that has +1, +2, -1, -2. This can be thought of as a last minute exposure adjustment in fractions of a “stop.” If your camera automatically establishes its settings and you see through the viewfinder or LCD that the image seems a bit dark or light (especially in the shadows or bright spots), you can adjust to positive to make it brighter or negative to make it a bit darker. The adjustments are usually made in 1/3 of a stop, and while they only “compensate” your exposure they are relied upon by all levels of photographers to get the shot they want. You should feel free to play with this feature as you create each image.
When shooting color images there is another important factor to consider with your new camera: white balance. Like most settings on your new camera, white balance can be set to auto and the camera will adjust itself as best it can, based on the color of the light it sees. Many photographers prefer to let the camera control “WB” while they concentrate on exposure and composition. However, to have an understanding of how white balance affects your image, let’s discuss it briefly.
To our eye, most light seems white or without color, but every light source has a different color, a simple example being the greenish glow of fluorescent tubes compared to the warm (yellow or orange) color of an incandescent light source. White balance in a camera adjusts in relation to the color of light in which you are shooting. In the world of film, white balance needs to be controlled by using filters or different film types, but for digital cameras, things are a bit easier. You can set neutral balance on your camera by using an 18% gray card. You simply take a photo of the card under the light in which you will be shooting; try to get all the card in frame, and depending on your camera, out-of-focus may work better.
After you have shot that image, go to the custom white balance setting in your camera’s menu and set white balance to match that image, tweaking the color values so the grays match in both the image and in real life. No fuss, no muss. An even simpler, although possibly not as accurate, way to set white balance in your camera is to go to the WB function in your camera’s menu and adjust the white balance settings to daylight, cloudy, incandescent, fluorescent, etc. and then check the results in live view or by taking a picture with that setting. If it’s to your liking, stick with it. White balance, more so than exposure, is subjective. You may like a cooler skin tone over a warmer tone, and unless you are shooting something (a product or fashion piece) that demands your image look just like the actual item, the coloring is up to you.
Finally, when getting to know your new camera, focus is as important as anything. Again, most lenses will autofocus until the cows come home and AF is an incredibly important tool for most photographers; however, there are times when it is faulty or times when manual focus is the best way to go. Examples of times when autofocus might not be preferred are when you are shooting in low light or shooting through something (a window) or shooting moving objects. In these cases, the camera will “hunt” for the subject to focus on and may not find it in time to get the shot. Also, while it is possible to adjust the focus points within your frame—and pro cameras have numerous AF points—autofocus often will attach itself to what is in the center of the frame even though you prefer to have the in-focus object in another part of the frame. To resolve this dilemma, your camera has an AF lock button, usually located near where your thumb rests on the back of your camera, often times near the viewfinder. After you have set the focus (manually or automatically) on what it is you want in focus, simply press and hold the AF lock button and recompose your image the way you would like, and then shoot.
Your DSLR will likely have three focus modes: manual, one-shot autofocus and continuous autofocus. Continuous autofocus is great when you are shooting multiple subjects or following a moving subject. However, again, depending on the quality of your lens and camera, the continuous autofocus can get confused and refocus when you don’t want it to. AF lock can again be called in to help. And of course, manual focus is always there for you if you need it, but as precise as it is, it can be as slow and inaccurate as we humans are. Practice will help that for sure. A perfect combination of auto and manual focus might be the best of both worlds and to that, a lens with manual focus override is the tool for you. It will autofocus as much as you need but will allow you to make the final critical focus without the need to change modes, or it will simply let you grab your lens barrel and focus your way if the autofocus keeps hunting without success.
All of the answers are right in your hand. You can adjust each of the settings and immediately see their effects. You can erase all your mistakes and start again. Take advantage of that and shoot until you are comfortable. Also, let the camera do its auto-thing and study what it did. If you want to grab a quick shot and don’t have time to think about ISO, take the shot on auto, but check the settings afterward to see what the camera chose and then see how you can improve upon it. One thing, though: keep on shooting.