Often in my videos, I’ll say that I exposed this image to the right or on another image I might say something like, I exposed this image to the left. Other times I might be heard saying that I exposed this one for the highlights or I exposed for the sky on this one. Invariably when I do say anything about exposing an image differently, I’ll receive emails from folks asking me to better explain what I meant by it as well as why and how I did it. Every now and than I even get an email from someone telling me why I was wrong to expose it that way!
In this article I’ll explain what Exposing to the Left (ETTL) and Exposing to the Right (ETTR) mean, and the advantages and disadvantages of exposing an image one of those two ways over exposing the image in a more balanced way.
Limitations of Digital Cameras
Todays digital cameras are a wonder of technology but the truth is they’re no comparison to the combination of the human eye and brain. The exposure latitude of a digital sensor is limited when compared to that which can be discerned by a human. With a digital camera, as tones get brighter in a scene they’ll become unrecordable with a digital sensor beyond a certain intensity, causing individual colors to saturate and the lightest textures to turn solid white — this is called, clipped highlights.
At the other end, cameras record fewer dark tones than that which can be seen with our eyes. Often we may perfectly expose a scene to find that the shadows lack depth, definition and color with a bulk of the subtle darker tones showing as absolute black — this is called, clipped shadows.
A Photographer’s Strategy to Deal with Digital Camera Limitations
As a photographer we’ll often assess a scene making a decision as to which tones are most important to the scene and set our camera’s settings in such a way to ensure that those tones be recorded without clipping. Say for example that a landscape scene has a beautiful expansive bright sky with several large fluffy white clouds. If a photographer feels that the detail in those clouds is the most important thing to the scene, then they would want to preserve detail in those clouds and the sky by exposing for the sky — often called exposing for the highlights.
On the other hand, say the scene is under the canopy of a rain forest. The majority of the tones will probably be darker with a lot of detail in the shadows. In that case, the photographer will likely prefer to expose in such a way that would favor those darker tones — often called exposing for the shadows.
Recitation of Terms
The terms Exposing to the Right (ETTR) and Exposing to the Left (ETTL) refer to the way a histogram looks for a given image that is exposed in such manner.
Expose to the Right (ETTR)
An image is exposed in such a way so the histogram is shifted as far right as possible without clipping the highlights. The image will look over-exposed. In post, the image is adjusted to a more standard exposure. This is sometimes referred to as Exposing for the Shadows.
Main Advantages
- Minimizes image noise because with todays image sensors, darker tones tend to be recorded with more noise than lighter tones.
- Maximizes the number of tones recorded because todays image sensors tend to not record as many shadow tones as highlight tones. Exposing to the Right allows the sensor to work more in it’s “sweet spot” maximizing tones and detail.
Main Disadvantages
- High risk of clipping the highlights since there is less forgiveness when exposing to the right.
- High risk of unrealistic color shifts because one color channel may clip before another causing colors to change, often dramatically.
When and How to Employ
Say you’re below the canopy of that rain forest. It’s relatively dark and damp in most places with a bit of light streaking in here and there. There is interest and detail everywhere whether it be in the shadows or in those streaks of light beaming down through the canopy of trees. You come to realize that if you expose more toward the middle, much of the detail in the shadows will be lost as well as much of the detail in the highlights — the dynamic range of the scene is just too great to record if your exposure is balanced. You make the decision to expose to the right. You’re going to over-expose the scene a little to make sure that your camera captures all the detail in the shadows with as little noise as possible. You’re probably going to sacrifice much of the detail in those streaks of light but it’s the creative decision you choose.
To accomplish:
- Set your camera to spot metering
- Meter one of the darker things in the scene before you that you want to ensure retains detail in your image.
- Remember that exposure setting or keep holding the shutter button halfway-in to hold that exposure in your camera as you recompose the scene to your liking.
- If you held the shutter button halfway-in to hold exposure, take the picture after recomposing and verifying focus. If you didn’t hold the shutter button in halfway but instead took note of the proper exposure, set your camera to manual and tune the settings to that noted exposure then take the picture.
- In post you’ll have to add some negative exposure compensation and bring down the highlights and whites in the scene.
A Real World Example
When using a flash it’s a bit easier to expose to the right. All one needs to do, if shooting manually, is turn the power up on their flash enough so the histogram gets effectively pushed to the right without excessive clipping of the highlights. If utilizing automatic flash such as ITTL or ETTL, merely adding some positive flash compensation will push the histogram to the right.
While photographing the eye of one of our cats, I made the determination that the detail in her iris was of utmost importance. The iris was relatively light but there were a lot of capillaries and subtle shades of color in her eye that I wanted to make sure were captured with as little noise as possible so I decided that I’d expose to the right. I was using a Nikon D800e with a Sigma Ring Flash. First I determined the “correct” balanced exposure of the scene then turned the flash power of the ring flash up enough to overexpose the scene by about a 2/3rds of a full stop. There wasn’t a lot of white fur that could blow out and if it did, I didn’t feel it would hurt the resultant image.
In post, the most important thing I needed to do was to bring the total exposure down as well as the highlights. I believe I ended up adding minus 9-tenths of a stop (-0.9) negative exposure compensation that actually ended up underexposing the image a bit. Here is the result:
You may be wondering, “He could have done the same thing with a normal exposure” — I of course would disagree. There are so many subtle, near black, but not absolute black, capillaries in her eye that would have been recored as pure black if I balanced the exposure causing the image to appear to be flatter and less dynamic. More importantly, the noise would be increased thereby decreasing the detail of a highly detailed image.
Expose to the Left (ETTL)
An image is exposed in such a way so the histogram is shifted as far left as possible without clipping the shadows. The image will look under-exposed. In post, the image is adjusted to a more standard exposure. This is sometimes referred to as Exposing for the Highlights.
Main Advantages
- Preserves detail in the highlights and avoids color channels being clipped causing color shifts.
- Requires less light which may allow a lower iso thereby offsetting any increase in noise one might encounter in the shadows.
Main Disadvantages
- High risk of increased noise in the shadow tones because the darker, noisier tones will be brightened in post.
- Fewer discreet tones are captured by the camera.
When and How to Employ
Whenever you have a situation where the highlights of the scene are of most interest or contain the most detail, you’ll likely want to expose to the left (ETTL). Situations such as this are quite common in landscape scenes that have expansive, interesting, yet bright skies. If your exposure is balanced, you run the risk of blowing out the sky losing detail so you make the decision to expose for the sky — expose for the highlights — expose to the left so you’re sure that the detail in that beautiful sky is recorded.
To accomplish:
- Set your camera to spot metering.
- Meter the sky. Simply point your camera up at the sky and get a reading.
- Remember that exposure setting or keep holding the shutter button halfway-in to hold that exposure in your camera as you recompose the scene to your liking.
- If you held the shutter button halfway-in to hold exposure, take the picture after recomposing and verifying focus. If you didn’t hold the shutter button in halfway but instead took note of the proper exposure, set your camera to manual and tune the settings to the noted exposure settings then take the picture.
- In post you’ll have to add some positive exposure compensation, open up the shadows and set the black point for the picture. If the image has a lot of noise, you’ll have to use the detail panel in Lightroom to lessen it or a plugin such as Topaz Denoise.
A Real World Example
I wanted to get a dramatic shot of the statue of David. The sky was stunningly detailed but very bright causing the statue to be backlit and very dark. I made the decision to expose for that dramatically detailed sky and to deal with the backlit David and any resultant noise in post. I simply metered for the sky and ended up with this:
This image was a bit more complex to post process so I actually had to bring it into Photoshop to mask out the sky so that I could more effectively work on David without him haloing. When finished, I ended up with this:
You’re probably thinking that the processed image of David was an HDR shot. I assure you it isn’t. I did have to bring ole’ Davey over to Photoshop, mask out the sky and put him alone to his own layer. Doing so allowed me to do the work needed to bring out the detail in his body without causing excessive haloing.
Balanced Exposure
Truth is, most scenes look great when exposed normally. This is particularly true in more controlled situations such as in a studio or on a model shoot.
If you’re just starting out in photography you may not immediately recognize when a scene would benefit to be exposed to the right or left. I encourage you to use the histogram on your camera — it will help you to more intimately understand the scene before you so that you can effectively capture it. Also, turning on the highlight warning feature of your camera will cause any blown out parts of the image to blink when you chimp the shot. If you’ve ever heard a photographer say that he has “blinkies turned on” that means he has the highlight warning turned on.
Post processing programs such as Lightroom have features that will display blown out highlights or clipped shadows in a more obvious way. Of course seeing them in Lightroom after the fact may be of little use to the image at hand but I believe if you utilize these features and get familiar with them it will go a long way helping you recognize when a live scene might induce blown out highlights or clipped shadows.
Is One Way Better than the Other and Which Should You Use?
Often I hear a photographer say something like “I never expose to the left. Too much noise.” One time I read an article where a photographer wrote that there’s never a situation where he feels that he should expose to the right. Well, to me, those attitudes are very limiting and stunting. I’m reminded of a biography I read when I was a kid about the golfer Jack Nicklaus and I hope you don’t mind if I use it as an analogy.
As a young pro golfer, Jack Nicklaus could very effectively, as you might imagine, hit the ball straight. He also, when needed, could very effectively hit the ball causing it to begin to fly straight then curl several yards to the right before landing. This is called hitting a fade (for a right handed golfer). What Nicklaus couldn’t do very well was the opposite — hit the ball straight with a small right to left tail on the flight. This is called hitting a draw (again, for a right handed golfer).
Nicklaus found that most golfers on the tour could do one or the other very well but not both. Some could effectively hit draws while others, like him, more effectively hit fades. Furthermore he noticed that some golf courses were laid out to favor one type of ball flight over the other. One such course that favored a golfer that could draw the ball was The Augusta National Golf club where the Masters Tournament is played.
Jack wanted to win a Masters title but the layout of the course wasn’t suited to his fade so he had to learn to effectively draw the ball. He of course did. He ended up winning 6 Masters Championships and finished second 4 more times. He has been quoted as saying that he would not have won a single Masters if he didn’t learn how to effectively draw the ball.
Being able to hit the ball straight and with a fade then learning how to draw the ball allowed Jack Nicklaus to be the best golfer he could be and one of the best golfers of all time.
Learning how to produce a properly exposed picture along with learning how and when you should expose to the right or expose to the left will make you the best photographer you can be.
