The first step in becoming proficient at any of the manual exposure techniques discussed below is to familiarize yourself with the quick and precise adjustment of your camera’s shutter speed, aperture, and ISO values. The second step is learning to adjust your camera’s metering modes. The remainder of this guide assumes you’re comfortable with both. The third step is to remember everything you’ve learned about the aesthetic and technical aspects of shutter speed, aperture, and ISO, and put that knowledge into practice. Lastly, it’s important to understand that both this and the following section focus on manual exposure, not manual focusing. Too often, students and beginners mistakenly believe that manual mode requires manual control of everything, which can be intimidating. Fortunately, this is not the case; in fact, the only contemporary camera systems where this is true are Leica’s M‑series, which lacks automatic or semi-automatic focusing.
Is manual exposure necessary?
Memorable photographs, especially landscapes, are often the result of lighting conditions that are distinctly ‘not average.’ Under these unusual circumstances, normal rules and automation will probably fail to produce the fine, expressive photograph you have visualized.
–John P. Schaeffer
Manual exposure allows you to take control of your image. It encourages you to pause and apply a more deliberate approach to your photography, freeing your mind from the tendency to snap pictures thoughtlessly at every opportunity. In this way, it helps you make creative decisions with purpose.
Modern cameras offer multiple ways to achieve the same exposure. Many advanced and professional photographers rely on their camera’s auto-exposure settings to quickly and effectively capture images. However, there are also situations where manually setting the exposure is the best or only viable technique for achieving the image you envision. You’re encouraged to experiment with different methods and discover what best suits your style.
Ultimately, manual exposure isn’t necessary in most photographic situations. Nevertheless, understanding how it works and how to use it to achieve desired results will be helpful in situations that require it.
Sunny ƒ/16 rule of thumb
Every photographer should know this rule of thumb: when your subject is in direct sunlight, set your exposure to ƒ/16 and a shutter speed that matches the reciprocal of your ISO value. For example, with a camera set to ISO 200, the correct exposure for a subject illuminated by direct afternoon sunlight on a clear day will be ƒ/16 and 1/200 second. If you need less depth of field or a faster shutter speed, adjust the proportions according to the reciprocity law. An equivalent exposure at the same ISO would be ƒ/11 and 1/400 second, ƒ/8 and 1/800 second, and so on.
Copy your auto-exposure values
In situations beyond direct sunlight, one of the easiest techniques for beginners to experiment with manual exposure is by copying the auto-exposure settings. This involves taking several trial images using your preferred auto-exposure mode and analyzing the exposure values. If you like the results of a particular shot, switch your camera to manual mode and replicate the shutter speed, aperture, and ISO settings.
Use a handheld incident-light meter
A more advanced, yet straightforward and accurate technique, especially for portraits or subjects within reach, is using an incident-light meter. Contemporary light meters operate in either Aperture Priority or Shutter Priority modes. In both cases, you set the ISO value and either the shutter speed or aperture (depending on your desired effect), and then take a reading of the incident light from the subject’s position with the lumisphere pointing towards the camera. After taking a measurement, the meter will display the correct exposure values based on the light reading and your chosen settings.
For example, if you want to take a portrait in open shade on a sunny day, and you’ve decided that a narrow depth of field is important, you might choose ƒ/2 and ISO 200. If the light meter indicates that a shutter speed of 1/1000 second is needed, you would adjust your camera’s settings accordingly. If you’re using a large and complex lens, you might need to adjust the exposure values slightly to compensate for differences in the lens’s transmission value (see F‑stops and T‑stops in Aperture).
Use the camera’s reflected-light meter
The most accessible method for manually setting exposure values is to use your camera’s built-in reflected-light meter. With practice, this process becomes simple and takes only a few seconds. However, it depends on the scenario’s complexity and how comfortable you are with your camera’s controls. Before you begin:
- Familiarize yourself with how and where your camera displays exposure information in the viewfinder or on the LCD. (Typically, it’s ordered from left to right as shutter speed, aperture, and ISO.)
- Select the appropriate metering mode for the scene, such as evaluative, matrix, or multi-pattern metering.
The large notch (or zero) at the center of the light meter scale in your viewfinder designates the standard exposure index, which represents the camera’s idea of optimal exposure. This “optimal” exposure is influenced by the chosen metering mode. In manual mode, the exposure level indicator shows how your set exposure values deviate from this standard index.
Remember, the exposure level indicator is dynamic and can fluctuate wildly based on the part of the scene your camera is aimed at, especially in spot metering mode. Setting your exposure values manually using the camera’s exposure meter is straightforward, regardless of whether you’re using an optical or electronic viewfinder, live view LCD, or rangefinder. The remainder of this guide assumes you’re using a DSLR with an optical viewfinder, but the process is similar across most cameras.
After composing your image, check the exposure meter and note where the exposure level indicator sits relative to the standard exposure index. If the indicator is on the positive side, the camera is advising that your current settings will result in overexposure. If it’s on the negative side, it’s advising underexposure. Adjust your settings accordingly to align the indicator with the index mark for what the camera considers “correct” exposure.
For example, if your camera is set to 1/80 second, ƒ/1.4, and ISO 1600, and the exposure level indicator is at +2 EV, the camera expects your settings will overexpose the image by two stops. To correct this, adjust one or more of the parameters by –2 EV. How you reach the total compensation of –2 EV doesn’t matter (see Reciprocity Law). In this example, if the shutter speed and aperture are appropriate for your subject, reducing the ISO to 400 (–2 EV) might be the best option for lower noise.
Of course, blindly following the light meter’s advice in manual mode is no different from relying on auto-exposure modes. Use your judgment as a photographer to understand the subject, the scene, and where the camera’s program might err. For instance, photographing a person in bright clothing against a bright background might require shifting the exposure indicator to +1 EV to +1½ EV for an accurate representation, rather than aligning it with the standard index. Conversely, a subject dressed in dark clothing against low-reflectance foliage might be better exposed by shifting to –1/2 EV to –1 EV.
With practice and repetition, operating your camera’s exposure controls will become instinctive and guided by muscle memory. So, get out there and practice.