A method comprising: operating, by a computing device, a first image-capture system to capture first image data of a scene, wherein the first image-capture system initially uses a first value for a first image setting to capture the first image data; and while the first image-capture system is capturing the first image data: operating, by the computing device, a second image-capture system to determine an updated value for the first image setting, wherein the first image-capture system and the second image-capture system are arranged on a given device and oriented in substantially the same direction; and sending an instruction to the first image-capture system that indicates to use the updated value for the first image setting to continue to capture the first image data, wherein the first image setting comprises an exposure setting for the first image-capture system, characterized in that operating the second image-capture system to determine an updated value for the first image setting comprises: operating the second image-capture system to capture a plurality of second images of a scene, wherein each image of the plurality of images is captured using a different value for the exposure setting; downsampling the plurality of second images; constructing a pixel-value histogram based on pixel values of the downsampled images; comparing the pixel-value histogram to one or more reference pixel-value histograms; and determining the updated value for the exposure setting based on comparing the pixel-value histogram to the one or more reference pixel-value histograms. operating, by a computing device, a first image-capture system to capture first image data of a scene, wherein the first image-capture system initially uses a first value for a first image setting to capture the first image data; and while the first image-capture system is capturing the first image data: operating, by the computing device, a second image-capture system to determine an updated value for the first image setting, wherein the first image-capture system and the second image-capture system are arranged on a given device and oriented in substantially the same direction; and sending an instruction to the first image-capture system that indicates to use the updated value for the first image setting to continue to capture the first image data, wherein the first image setting comprises an exposure setting for the first image-capture system, characterized in that operating the second image-capture system to determine an updated value for the first image setting comprises: operating the second image-capture system to capture a plurality of second images of a scene, wherein each image of the plurality of images is captured using a different value for the exposure setting; downsampling the plurality of second images; constructing a pixel-value histogram based on pixel values of the downsampled images; comparing the pixel-value histogram to one or more reference pixel-value histograms; and determining the updated value for the exposure setting based on comparing the pixel-value histogram to the one or more reference pixel-value histograms. operating, by the computing device, a second image-capture system to determine an updated value for the first image setting, wherein the first image-capture system and the second image-capture system are arranged on a given device and oriented in substantially the same direction; and sending an instruction to the first image-capture system that indicates to use the updated value for the first image setting to continue to capture the first image data, wherein the first image setting comprises an exposure setting for the first image-capture system, characterized in that operating the second image-capture system to determine an updated value for the first image setting comprises: operating the second image-capture system to capture a plurality of second images of a scene, wherein each image of the plurality of images is captured using a different value for the exposure setting; downsampling the plurality of second images; constructing a pixel-value histogram based on pixel values of the downsampled images; comparing the pixel-value histogram to one or more reference pixel-value histograms; and determining the updated value for the exposure setting based on comparing the pixel-value histogram to the one or more reference pixel-value histograms. operating the second image-capture system to capture a plurality of second images of a scene, wherein each image of the plurality of images is captured using a different value for the exposure setting; downsampling the plurality of second images; constructing a pixel-value histogram based on pixel values of the downsampled images; comparing the pixel-value histogram to one or more reference pixel-value histograms; and determining the updated value for the exposure setting based on comparing the pixel-value histogram to the one or more reference pixel-value histograms.