The most important technical aspect of photography is exposure. Since photography is simply a sensor recording light in various depths, the exposure – how much light reaches the sensor – is something you need to know how to control. Ultimately, that means you have to adjust your exposure to fit the lighting conditions. This post will discuss:
- best practices when exposing your images
- what to look for on your camera
- how to adjust your exposure when it’s wonky
If you haven’t read my post on the exposure triangle and are unfamiliar with aperture, shutter speed, ISO, and light meters, I suggest reading that first. Otherwise, a lot of what I will cover here won’t make sense.
Alright, let’s get into it.
Best Practices to Adjust your Exposure
Expose to the Right
I will write another post in further detail about the histogram of an image. What’s important to keep in mind when searching for optimal exposure is to expose to the histogram’s right, just short of blowing any highlights out.
Here is a series of histograms for your reference:
Here are some examples of images with their histograms.
You can see that the left-hand column images look better overall, with their histograms mostly centred. However, the shadows of the images are rather dark. In post-production, we can bring out those shadows, but that will produce a significant amount of grain: not ideal.
The images in the column on the right look quite overexposed with the highlights lacking depth and detail, but the shadows are exposed well. Those histograms are excellent examples to aim for when shooting because it gives us maximum control when post-processing.
On the histograms, you can see that the highlights are not blown out completely; they still fall slightly toward the centre. This is an important detail. If they are touching the right side, that means that all detail is gone in those areas, never to return; the sensor has no information to work with. That’s not good.
If you are working in Lightroom, the small, upturned arrows inside of the histogram indicate clipping – complete loss of information – in the image. Furthermore, you can click on those arrows, and Lightroom will highlight, on the image, where the clipping is occurring.
The underlying reason we want to expose to the right, as opposed to the left, is that there is more detail on the right. I said earlier that bringing out shadows results in grain and noise. That’s because there’s not as much detail available there to begin with. Contrastingly, there is a lot of detail available on the right, making the highlights easier to tone down while retaining quality. Again, more on how to read a histogram another time.
Key Takeaway
Though clipping is not good when shooting, it can be desirable for the final product, depending on your vision. However, while shooting, keep the histogram to the right, while not touching the right, so that you have full control later on.
Utilize Exposure Bracketing
We all inevitably face some extra tricky exposure situations. Often, extreme contrast in lighting is the culprit: a bright, sunlit sky with shadowy land or dramatic side or backlighting on a dark subject. Where possible, use the method above. However, sometimes that results in clipped shadows – shadow information underexposed far to the left – with no information whatsoever in that direction. In these cases, I recommend setting yourself up for some more post-processing options with exposure bracketing.
Exposure bracketing is a feature of most digital cameras where the camera will take three or five shots at varying exposures. In Settings you can adjust at what range of exposures (a full stop, half a stop, a third of a stop, etc.) and how many (one each way, or two each way) around your set exposure it takes. The result will be either three or five shots: one or two captures underexposed by one, half, or a third stop; one capture correctly exposed as you’ve dictated; and one or two captures overexposed by one, half, or a third stop.
In the end, this feature offers flexibility in the editing process. You have several images, each with different exposures that allow you to cut, paste and adjust the final product to have optimal exposure everywhere.
Key Takeaway
Use the exposure bracketing feature to captures several exposures in difficult lighting conditions. You will have a few different options to choose from and enough information to work with post-processing.
Choose the Right Metering Option
To optimize your light meter, there are a few options to choose from that determine how your camera sets the exposure.
Different cameras may have more or fewer options, but my camera has four:
- Matrix – The camera meters a wide area of the frame taking in the most information. This is suitable for normal conditions.
- Center-weighted – The camera meters the entire frame but places more weight on the centre area. This is suitable for portraits or sometimes useful when using exposure-adjusting filters.
- Spot – The camera meters a single spot (approximately 1.5% in diameter of the frame). This is suitable to ensure correct exposure of a smaller single target while its surroundings are much brighter or darker.
- Highlight-weighted – The camera meters with the greatest weight placed on the highlights. This is suitable to ensure strong highlights are not blown out (for example, spot-lit performers on a stage).
Understanding these options and how and when to apply them to various lighting conditions can make using the light meter more effective.
Key Takeaway
Know where and how to adjust the metering options on your camera. Depending on the lighting situation, one of these options may be more appropriate than another.
Key Camera Functions to Adjust your Exposure
Histogram
Mirrorless cameras can offer a histogram displayed right inside the electronic viewfinder, which is handy. Otherwise, DSLRs will give you an option to display the histogram in playback. As I said, I will write a dedicated post on how to read the histogram, but start with learning where to find it (and exposing to the right).
Light Meter
The light meter should be displayed virtually everywhere on your camera: in the viewfinder, on the display screen, and the control screen, if your camera has one. In my post on the exposure triangle, I explain how to read your light meter, so check that out if you’re unsure.
Exposure Bracketing Control
Whether there’s a shortcut button somewhere on your camera body or the control is in the menu, learn where you can set your exposure bracketing. It’s helpful to be able to do this quickly for unexpected scenarios.
Metering Options
Like exposure bracketing, this control could be a shortcut button or accessible in the menu.
Exposure Compensation
This setting is a more stylistic adjustment than a practical one. Exposure compensation is simply ordering your camera to under or overexposure your shot by the amount you dictate. Therefore, regardless of your shooting mode or metering choice, whatever the camera determines is the correct exposure, it will override to capture the image at the exposure compensation you set. Again, this is more for stylistic purposes if you prefer the image to be intentionally under or overexposed. Regardless, it’s good to know where to find that setting.
How to Adjust the Exposure when it’s Wonky
In the post about the exposure triangle, I explain how to add and subtract stops of light using shutter speed, aperture, and ISO. Balancing these three variables is the basis for adjusting the exposure of an image. However, that post covered the technical side of the exposure triangle. Here, I will run through a brief explanation of the aesthetic effects of adjusting shutter speed, aperture, and ISO beyond exposure.
Shutter Speed
This variable is undoubtedly the simplest to understand. The shutter speed is the speed at which the shutter opens and closes.
A fast shutter speed freezes moving objects in the frame like a running soccer player, falling leaves, or crashing waves. A slow shutter speed produces motion blur like car light streaks, a blurred waterfall, or moving pedestrians on a sidewalk.
Adjusting the shutter speed is a stylistic choice as much as it is a technical one, but it’s also practical. If you take handheld photos, camera shake can be an issue with slower shutter speeds. Depending on your camera and lens combination, you will typically experience camera shake at less than 1/60th of a second. If you have to shoot that slow, I recommend using a tripod.
Key Takeaway
You can adjust your exposure by stopping up or down using shutter speed, but it does have a stylistic effect (either intentionally or unintentionally) on the image in the way of motion blur or freezing.
Aperture
Aperture is slightly more challenging to explain. Simply put, it affects how much of your image will be in focus. A low aperture will result in a smaller plane of focus (narrow depth of field), where a high aperture will result in a larger plane of focus (wider depth of field).
Here is a diagram that helps to explain aperture visually.
The decision on the aperture setting is in the hands of the photographer and their vision. For example, portraits are often taken at lower apertures to blur the background, where landscapes are usually taken at higher apertures to keep everything from foreground to background in focus.
Key Takeaway
Adjust your aperture to adjust the exposure but understand what a higher or lower aperture will do to the final image.
Side Note:
It is crucial to pay close attention to the focusing of your camera when using lower apertures; because it’s a narrower depth of field, it’s easier to miss the focus on your subject. Even a camera with excellent autofocus capabilities needs you to tell it where exactly you want it to focus.
ISO
ISO is relatively simple: a higher ISO will allow more light to the sensor, increasing the exposure. However, there is a trade-off. Shooting with a higher ISO, you will experience more grain and noise and less colour vibrancy and contrast in the image.
There is an excellent ISO test to perform on your camera because every camera will handle ISO differently.
Take the same photo at different ISOs, adjusting the exposure to be the same using shutter speed or aperture. Start at ISO 100 or so and increase to 6400 or 12800. Then, compare the RAW, unedited images side-by-side in post-production. You will likely see a significant difference at some point, but it’s up to you to determine when it becomes unacceptable. Now you know your maximum ISO for your camera and your personal preference.
Key Takeaway
Your ISO can act as a bit of a wild card with exposure, but it’s essential to understand how far you and your camera are willing and able to take it.
In Summary
There are a few best practices to keep in mind when exposing your image:
- Expose to the right of the histogram without blowing out your highlights.
- In extraordinarily harsh lighting conditions, utilize exposure bracketing to capture three to five exposures of the same image for maximum flexibility in post-production.
- Use metering options to have your camera set the exposure based on individual lighting situations.
Additionally, there are a few key exposure settings and controls on your camera to know:
- The Histogram
- The Light Meter
- Exposure Bracketing
- Metering Options
- Exposure Compensation
Know where to find and how to use these features to optimize each exposure on the fly.
Finally, understand the three variables to the exposure triangle and what they do to the aesthetic of your image:
- Shutter speed gives motion blur or object freezing in place.
- Aperture affects the depth of field and how much of your image can be in focus.
- ISO is a wild card, but pushed too high will result in grain, dull colours, and low contrast.
Conclusion
These are a few different factors to consider when adjusting the exposure of your image. As I mentioned in the post on the exposure triangle, some camera shooting modes allow the camera to do some of the work for you. However, it is still essential to understand what the camera is doing when using these modes. We don’t want any surprises in post-production!
I hope this post helped you learn how to adjust the exposure of an image effectively. It’s a balancing act, and it’s not easy to get it just right every time. Read your camera’s manual to learn where the features and functions are but then get out and take some shots! Practicing is the only way to get better.
Let’s give it a shot!