“Expose to the right” has been a popular saying and method of exposure for digital photographers for years, and it works in some cases. I’ll show you how to go the other way and make it work also. Maybe the time of “expose to the right” is almost over (in some cases). Here’s why…
The reasoning behind “expose to the right” was that if you pushed your histogram to the right when you took your shot, you would have less noise in your image, particularly in the shadow areas. This is because there is sensor noise and it becomes worse in any shadowed area. Why? Because the inherent noise in the sensor is visible when there is no light shining on the sensor to overcome it. Just try photographing an all black, dark scene, and deliberately underexpose it. You will see the noise in the image when you view it on the camera or in your computer.
Some definitions: "expose to the right" = bright image, you take the photo with the histogram primarily to the right (overexposed). "expose to the left" = dark image, you take the photo with the histogram primarily to the left (underexposed). "normal exposure" = balance of bright and dark over the full dynamic range of the camera sensor
“O.k., but what changed” you ask?
First, cameras have gotten way better at reducing the noise. You can shoot darker images (underexposed) now than ever before and not worry about too much noise showing up in your photo.
Second, software has gotten way better at removing the noise. Neat Image and even Lightroom itself are great at removing the noise.
Third, capturing and exporting photos in RAW format allows greater control of photos in software later. A larger range of adjustments can be made to reduce the noise. When shooting in JPEG, the camera imprints the noise right into the JPEG file, allowing less latitude for adjustments and less chance for good noise reduction later.
Fourth, underexposed images (exposed to the left) shot in RAW format can have their exposure adjusted upward in software (like Lightroom) and still maintain proper lighting throughout the photo. You’ll see why this is important next.
Fifth, slight underexposure will make your colors in the photo “pop.” The eye looks for the black in any image in order to “set” the color levels in the mind. Seeing good blacks makes the colors in an image look brighter. This is all in your head, but it works. Another way of looking at this is that the mind sees blown out highlights immediately. Just critique any photo and you will do this automatically. You rarely would look for areas of too much darkness (blacks). You see the highlights first and you disqualify the image if it is too bright in any areas. But silently, your mind is also looking for those dark areas to set the color range because luminosity sets the color (without luminosity there is no color (black)), so don’t distract it with too much highlight!
Sixth, with good blacks in an image from underexposing slightly (-1/3 to -2/3 EV), this makes the details look sharper to the eye. This is because there is a definitive black lining around features. This again works in your head. Your eye sees darkness near lighter/colored areas, and thinks that there is contrast (there is), and perceives the details as being sharper. All without you sharpening anything in post-processing! Now, if you sharpen in post-processing, just think how much sharper you can get your images! People will ask you how you did that.
The case for “expose to the left.”
“But, why do I want to ‘expose to the left’?”, you ask. Let’s look at the opposite: If I “expose to the right”, I have the potential to “blow out” the highlights in my photo. The highlights turn all white, like if you have ever taken a photo that had the sun in it and the core of the sun was just one white blob. You can not recover the detail in the blown out highlights. They are gone forever.
But, if I “expose to the left”, I will preserve those highlights and there will be detail left in them. The rest of my photo will look dark, but I can adjust the exposure upward afterward in my Lightroom or similar RAW processing software. Yes, I will have more noise in those dark areas, but I can use Lightroom or a dedicated noise-removal software package to take out the noise. It is more work, but the overall exposure of the final image will make it all worth it. The brighter areas of the image will be better-looking because they will have retained detail.
It is easier to recover detail in the shadow areas by increasing the exposure in post-processing than it is to recover highlight details when working with an overexposed photo. If you have ever tried to recover highlights in a photo editing program by brushing the areas, you know that the image you are working with becomes “muddier” looking. This is because you have lowered the brightness in the areas of your photo that should be bright, and have “flattened the colors” of the image. Sure the histogram is more to the middle, but the image has lost valuable dynamic range.
However, with an underexposed photo, those details in the shadows will come out when the overall exposure is increased. The highlight areas are then not overexposed, but increase along with the overall image exposure, keeping balance of light and dark in the photo as it was when you took it. The overall dynamic range is preserved, but just shifted upward without clipping.
Try it for yourself, and you will see that you can drastically improve your final images this way. Pay attention to the noise and reduce it to acceptable levels. Shoot in low ISO ranges as you should be anyway, and you’ll be all right. To “expose to the left”, besides going for a higher aperture f-number (smaller aperture opening) or a faster shutter speed (open for a shorter time allowing less light to enter), you can also just expose normally then hit your camera’s exposure compensation and take it down a notch of two (-1/3 to -2/3 EV). This is easiest for me.
Here are some additional reasons to expose to the left and not to the right:
- Chroma or color quality is not handled well by the camera sensor if there is too much light coming into it so exposing to the left gets better color from a purely technical point-of-view.
- Bright colors in the sky can be really affected by the expose-to-the-right approach.
Also remember that no rule is hard and fast. If you truly need the lowest noise image possible for stock photos or other purposes, then your camera noise will be lowest at low ISOs and when exposing to the right. So “expose to the right” in these cases.
Thank you for reading what I wrote — I hope you enjoyed it.