Making images separates snapshots from creative photographic images
For our purposes, I will treat “exposure” more broadly than its technical meaning. In this blog post I mean understanding and controlling the amount of light in an image, and such things as the aperture and shutter speed. The reason understanding these things is important is that they allow the photographer to progress from “taking” pictures to making images. And, makingimages is what separates snapshots from truly creative and sometimes even art-quality images. In order to truly understand this concept, we must understand that what the camera and lens capture is not what the human eye sees. We must understand how the mechanism captures light and images in order to effectively use it to create images that are pleasing and compelling.
If I had my way, I would teach all serious new photographers with a very simple, film camera with transparency (film). There would be nothing “automatic” on the camera and all settings would be required to be made manually. In my view, nothing highlights exposure errors and weaknesses better than a low-latitude, transparency film. But I won’t have my way. It is getting harder and harder to even find transparency film and it is only a matter of time before the same will be true of film based mechanisms. And today, the vast majority of new photographers start with digital point and shoot cameras. At the same time, the latitude (ability to capture a range of light in a given exposure) on the new sensors continues to increase over time. For those who are using the cameras to capture snapshots of family memories, events, etc., that is, of course, a boon. For those who understand the science of how exposure works, it is also a plus. As a learning tool for an aspiring photographer; not so much.
To truly understand these concepts, we need to first turn off the automatic settings and use our cameras manually
If you own a digital SLR or an advanced Point and Shoot digital camera, you realize that they all now have numerous “settings.” To understand how they work, you will need to spend some “homework” time reading the manuals. Why does the camera offer one setting that makes aperture size a “priority,” and another that makes shutter speed a priority? Why does it have these settings, in addition to one that just picks the “correct” combination of these for you? To truly understand these “automatic” settings, you must understand at a very basic level, how things like aperture, shutter speed, and controlling light quantity affect your images. Until you understand, and master, the concept of “correct” exposure and how to manually achieve it, the “automatic” exposure tools on today’s modern cameras will continue to be an impediment to making truly great exposures. Don’t get me wrong. I am not “bashing” the technological advances in modern cameras. I am only saying that in order to truly appreciate them, we need to get behind the scenes and understand their “dna.” And until we do that, we need to “turn off” all those fancy settings and use the camera as a “manual” tool. There are really only 3 controllable factors here: Aperture, shutter speed and sensor sensitivity (ISO speed).
The best way to “control” the quality of light is to understand when it happens and be there
The previous post in this series (Shoot in the Right Light) spoke about the quality of light. While we mentioned some ways to manipulate the light to alter or partially control the quality of light, we can probably agree that our ability to do so is limited, and that the best way to “control” the quality of light is to understand when it happens and be there. We can (and must) control the amount of light, however.
In my tutorial, “Getting Exposure Right,” I go into detail about how “f-stops” or “exposure values” work, how to meter the light and how that relates to the camera’s exposure sensor. I recommend reading that tutorial for a technical understanding—hopefully in a non-technical read, of exposure and exposure theory. I also reference Bryan Peterson’s “Understanding Exposure,” as, in my view, the best and most understandable explanation of these concepts by a very talented pro. My point, here, is not to re-hash those things. You must not only get the quantity of light measurement correct,but you must also make judgements about which parts of an image are most important in terms of “correct” exposure. In keeping with my premise that great photographs aren’t taken, but are made, you must understand—and you must control—these aspects of your photography in order to move to the next level.
The real important aspect to understand about aperture is Depth of Field
In my first tutorial, “How F-stops Work,” I detail (hopefully in a readable and understandable way) how the aperture and shutter speed settings work together on a camera. Again, I will not re-hash that here. I do want to address why understanding these things is important to making good images.
At its simplest level, aperture settings simply change how large or small the lens opening is. As the F-stops tutorial notes, this is really mainly elementary math. The larger the opening, the greater the quantity of light which strikes the exposure surface (film or sensor). Too much light yields a blown out image and too little, yields an image which is too dark with no detail. As the tutorial also explains, we can control the amount of light in two ways: by varying the aperture size or by varying how long the light is allowed to strike the surface (shutter speed). This begs a couple of questions in my mind. First, why does there need to be more than one combination of openings? And, second, if technology is so good, why not let the camera do all that stuff for you?
Modern lenses are only capable of rendering parts of an image sharp
To the knowledgeable advanced photographer, the aperture issue is much more important than “exposure.” The real important aspect to understand about aperture is Depth of Field (DOF). We often see discussion of the concept of image sharpness. In reality, we are talking about “apparent sharpness.” In terms of apparent sharpness, DOF is what our eye sees as apparently sharp from front to back in an image.
Unlike the human eye, modern lenses are only capable of rendering parts of an image sharp. The rest of the rendered image is unsharp to varying degrees. There is usually a segment of every image that is rendered apparently sharp. How wide (from front to back—admittedly a difficult concept in a 2-dimensional image) that portion of the image is, is referred to as DOF. Remember my comment earlier about not being able to capture what our eyes see? This is where understanding DOF—and manipulating it—is critical to our creation of good photographic images. In some cases, we want the entire image to appear sharp. But in so many others, we want out of focus parts of the image. Out of focus areas can creatively (and subliminally) emphasize our subject. The can cause the viewer to focus on colors, shapes and movement rather than details. Understanding how this works and using it to our creative advantage is what differentiates good photographic images from just “taking pictures.” If we let the technology do all these things automatically, without understanding what is happening, we give up the opportunity to create!
Controlling Shutter Speed
How F-stops Workalso covers the topic of shutter speed in terms of exposure. Once
more, however, this is but an elementary aspect of shutter speed. The true power in understanding shutter speed again lies in how we can use it to create images. The ability to control shutter speed gives us the ability to deal with motion. Sometimes, we want to use shutter speed to control motion; sometimes to suggest it. And, sometimes, we use it to create ethereal effects. Very fast shutter speeds do two things: they “freeze” subject motion and camera motion. The water spray in this ocean surf shot is frozen in the air by using fast shutter speeds. Slow shutter speeds can suggest motion (creating “motion blur”). They can also create an ethereal and very beautiful effect in some cases, particularly when there is moving water. I have been fortunate to get to know some very talented photographic artists over the years. One of my favorite photographers is working pro, Ray Laskowitz. Ray has an image on his website where he makes remarkable use of his knowledge of camera controls to create a very cool image of a classic car. I cannot think of a better way to illustrate my point. Ray has his knowledge of these things so internalized that he is able to put them out of his conscious mind, as he make some very creative images. His is a “next level” I aspire to (maybe several nexts J) Ray’s images are worth studying for creativity.
Flash can also be used enhance each of the above exposure controls. Most obviously, flash can be used to add light where there is not enough “quantity.” However, this is very limited, as the intensity of the flash at the point it is created dissipates extremely rapidly. As noted in the “Shoot in the Right Light” blog previously, flash may also be used in very bright conditions to even out strong shadows created (referred to as “fill-flash”).
Stroboscopic flash has an extremely short, but brilliant duration. This can be used to freeze action (it in effect overrides the shutter speed in many instances). If you understand how to use your flash, you can often combine motion freezing effects with motion blur in the same image for some great creative effects.
Use the Appropriate Tools to Create (rather than “take”) Photographs
Use them wisely, as tools of convenience, as you knowledgeably make your images
In order to achieve professional, creative photographic images, you must understand the theory of exposure and how each of the exposure controls relate to each other. You must also understand how the other areas discussed in this series relate to each other. You cannot, for example, achieve some of the slow shutter speed results without a tripod or other camera support. And there is often nothing to be gained from putting the above knowledge into play if you are not in place during periods of good light.
Once you understand what each of these controls are doing for you photographically, you can begin to use—and appreciate—some of the “automatic” features of your camera. But remember not to let those automatic feature dictate either the image or what you are doing. Use them wisely, as tools of convenience, as you knowledgeably make your images.