This is a guide covering exposure value.
In this glossary definition you’ll learn about:
- Exposure value definition
- How to calculate exposure value
- What exposure value scale is
- Normal exposure definition
- Some applications of exposure value
- And more
Have you ever entered a situation where your fellow photographers are talking about EV yet you don’t have a single shred of what they’re talking about?
Well, they are talking about Exposure Value, and in this article, we will explain everything you need to know about it.
Let’s dive in.
What is Exposure Value?
The exposure value is merely a method of combining your shutter speed and aperture into a single value.
Exposure value holds a more behind the scenes role if compared to your other accessories (think tripod, remote shutter release, Speedlite, etc.).
Photographers will use this term to talk about their exposure. To help you understand the concept of EV better you should understand exposure first. Exposure itself is the amount of light that you capture or record. You can control it by your aperture, shutter speed, and ISO. These settings physically impact the amount of light that can enter your camera.
Exposure is how much light we capture. Its value is connected to the camera meter that evaluates a scene. The value is then expressed via the exposure indicator on a positive and negative scale (+/-). In general, when adjusting the exposure triangle you aim to bring the exposure indicator to zero. This exposure indicator is essentially your exposure value.
Why the exposure indicator? Because the exposure indicator is connected to your camera’s meter, which is technically the camera’s brain. The camera meter will measure the average brightness of a scene and it wants the average brightness to be 50% so it’s well exposed.
Not every photo should be at zero exposure value, photographers and scenes will usually require their images to be brighter or darker. For artistic purposes.
How Do You Calculate Exposure Value?
To calculate the EV for a certain setting, you’ll most likely use this absolute exposure value formula:
The N is your f-stop, while the t is for Shutter Speed. Just like in other formulas, you will often find a couple of combinations that result in the same EV.
This formula is pretty old school and it assumes that you will not change from the basic ISO (ISO 100).
Looking at the exposure value formula at first glance does raise some interesting questions. Such as the side effects of shutter speed and aperture, their ability to change the depth of field, and motion blur.
I think it’s a good time to explain the difference between exposure value and ISO.
Using ISO can be one of the best ways to increase your EV without messing with the already calibrated aperture and shutter speed. ISO allows you to increase the EV by approximately 3-4 stops before noise becomes visible.
Usually, to reach the desired EV, photographers would either increase or decrease their ISO or shutter speed.
They do not really change the aperture unless they are deciding to change the depth of field. If your concern is just brightness, you can change any setting to reach your desired EV.
On your exposure indicator will be a plus and minus side with single-digit increments. In between those single digits there is some marking that is for ⅓ increments.
Smaller increments allow you to be more precise with your measurements and adjustments.
What is the Exposure Value Scale?
More often than not, the EV scale will range from around -6 to +17. Although in theory there are no limitations to go in both directions. If you choose a setting of f/22 and a shutter speed of 1/4000 for instance, you’ll likely achieve a +21.
Sadly, these settings are too dark for most of your photography subjects and scenes unless you crank up the ISO.
The less light that your shutter speed and aperture captures, the larger your EV number is. So in a nutshell, a darker setting will give you greater EV and vice versa.
EV is commonly used to describe the camera setting you use and also the brightness of a particular scene. Which makes a higher EV translate into a setting for shooting a bright subject/scene. As a point of reference, a bright midday scene would usually need an EV around +15.
Your combination will determine how much light your camera will capture. For darker scenes or low light conditions, a low-value EV such as -5 can help you avoid potentially underexposing the image. Here is one of the many exposure value charts that are available online:
Don’t forget that increasing or decreasing by one “stop” will double or halve the amount of light entering the camera respectively. This also applies when decreasing the EV by one value.
If an EV of 2 captures some amount of light, then EV 3 will half that amount of light, and so on. On the other hand, an EV of 1 will double the amount of light from an EV of 2.
Interestingly, the amount of EV that you need will never stay the same for different conditions. Although it might be obvious that both aperture and shutter speed affect the exposure, motion blur, and depth of field.
There exist some benefits to reviewing your images and the EV you took it in.
A post-production application can easily help you go through the process of sorting images based on their ISO’s.
There might be a certain amount of EV that you frequently use, a pattern for certain photographs or some correlation between two different situations that use the same EV value.
By carefully examining your work at the end of the day, you can get a better understanding of properly exposing your photos.
The topic itself isn’t something that every photographer must master, but it does go a long way if you choose to implement it.
What is Normal Exposure?
The term normal exposure is used to describe levels of exposure that are similar to what we normally see. So when your exposure indicator is zero, it is equivalent to normal exposure. Not underexposed and not overexposed.
You can achieve this by balancing out the exposure triangle (exposure, shutter speed, and ISO). Although, being able to create the normal exposure doesn’t give you a mastery of exposure.
As normal exposure is good, knowing how to be creative with it is more important. Professional photographers will sometimes overexpose or underexpose their subjects/scenes to create their desired atmosphere.
Starting with the depth of field to sharpness, all of those elements should be balanced and intentionally adjusted.
By getting the basics done with the help of an exposure value or absolute exposure value chart, you will get one step closer to mastering exposure.
The concept may be old and a bit outdated, but it still has its uses. Whether it be for buying cameras or laying a solid foundation for learning exposure.
It will also be particularly useful for your photography blog and flexing your knowledge on a technical term in the community.
What Are Some Applications of Exposure Value?
At first, the concept of EV may sound unnecessary when taking images in a real-life situation. Even professional photographers tend to look at their histogram to review an image if its overexposed or underexposed.
They will also just manually adjust their settings based on their preferences and needs.
Always keep in mind that some concepts may seem inapplicable to certain situations, especially when you’re just learning how to incorporate them.
EV may not be something photographers would instantly flock to once they know how it operates.
Fortunately, EV still has its practical applications even if unnoticed. Your knowledge around EV can help you when deciding cameras to purchase, since manufacturers may advertise it using the EV value. This context allows your full understanding of EV to help you recognize the capabilities of your camera.
Also manufacturers nowadays often do not fudge up their EV numbers by using a wide aperture lens for the measurements. Sometimes manufacturers will use EV to describe the camera’s dynamic range and the camera’s ability to auto-focus at low light conditions.
In theory, a dynamic range of 14 EV means that the camera can capture detail over 14 stops of EV. Most of this information is unimportant unless you really need information about light sensitivity.
Oh, you could use the absolute exposure value chart and formula to help guide you when shooting in new conditions. But, for me, it feels like my photos are less personalized and it feels like I’m shooting in automatic.
Using it as a reference for future photo sessions will be useful, hence the reason I think it is useful to help your understanding of exposure.
So, let us wrap up this article:
- So, what is exposure value? Well, it’s an old-school technical term for measuring your exposure. It is connected to both your exposure indicator and helps to measure the brightness of your scene.
- There is an absolute exposure value formula that uses shutter speed and aperture. Higher EV value is suitable for brighter scene and lighting conditions, while the lower EV is more suitable for low-light conditions.
- You can reach a higher EV by just raising the exposure triangle. If you have any concerns about the depth of field and sharpness you can easily raise the ISO settings. Most cameras nowadays can go up to 3200 ISO without emitting visible noise, which is probably 3-4 stops.
- The exposure scale will typically range from -6 to +15. In theory, there may be higher or even lower EV but in practice it may be less realistic. When used, it may be useless because a 1/22 aperture and 1/4000 shutter speed would be extremely dark. This makes it pretty useless in day-to-day photography.
- Normal exposure is an exposure that is similar to how your eye perceives the environment. Using your chart, you’ll get a better understanding of normal exposure. This opens the door to future artistic manipulation of exposure, maybe making it more dramatic, more mysterious, or more upbeat, the list goes on!
- The current applications of exposure value are quite minimal. It does help you understand the information used by manufacturers to sell their products. Photographers nowadays rely more on their histogram and exposure triangle.
The usage of EV may not be practical. A little work in EV goes a long way in the photography business you know since it does help your basic exposure understanding. Try it out and good luck!