A Deep Dive Into Match Total Exposures in Lightroom Classic

There's a function in Lightroom Classic that most users don't know exists and even if they do, they probably don't understand how it works (this was me at one point). Let's dive in.

What is Match Total Exposures and When Should You Use It

Suppose you have two images photographed in the same lighting condition with different camera settings and want the overall exposures to match. In that case, Match Total Exposures will automatically calculate the appropriate exposure slider value so that the target image(s) match the reference image.

Let's look at a real-life example. The two images below were shot with two different cameras with two different settings. The image on the left was shot at 1/320, f2.8, ISO 250 while the image on the right was shot at 1/320 at f3.5 and ISO 160.

For both images, the exposure slider is set at 0. As expected, the image on the right is darker. The images have the same subjects in the same lighting situation with different camera settings. You could increase the value of the exposure slider on the image on the right until it visually matches the image on the left. However, there's a better way!

This is a perfect opportunity to use Match Total Exposures to get the images to match in overall exposure. Let's run Match Total Exposures using the image on the left as the reference and the image on the right as the target image.

The exposure on the slider value on the right image was changed to 1.29 after Match Total Exposures was performed in Lightroom Classic.

Super important note — Match Total Exposures should only be used in situations where the subject matter and the lighting conditions are the same. Otherwise, Match Total Exposures will not produce the desired result. A great time to use Match Total Exposures is in wedding photography where two photographers are using different camera settings to photograph the same subject at the same time under the same lighting conditions. I could go into a deeper dive on the math that is used to calculate the resulting exposure slider value (it's a calculation that uses exposure value) but I will leave that for another blog post. 😉

How Do I Perform Match Total Exposures

First, select your reference image and then select the target images. The active image (highlighted slightly more) is the reference image, the other images selected will be the target images. In the example below, the reference is image 4 and the target images are 5 and 6.

Then you can trigger Match Total Exposures in Lightroom Classic using a few different methods.

1. Select the menu item, in the Develop module go to Settings > Match Total Exposures

2. Use the native Lightroom Classic shortcut which is Option + Shift + Command + M

3. Use Power Keys to remap Match Total Exposure to something simple, like Command + M

Using Match Total Exposures can really speed up exposure adjustments when used in the appropriate situations.