5 Replies Latest reply on Mar 30, 2016 8:29 AM by trshaner

    Best way: Adjusting exposure values for many images.

    GuJam

      Hello

       

      I am researching issues that occur with small unmanned craft used for aerial imaging in farming type situations.

       

      The issue I am working on now deals with changing light values for a single subject. Lets say I am photographing alfalfa and I have my camera set for a specific light value (we dont use auto anything for reasons I'll not get into now) during the duration of the image capture process lets say a thin cloud rolls by and it drops ambient light by a 1.5 exposure value. During this time I capture 50 photos the cloud goes about its business and im back to my initial light value. When I create a mosaic image from this set the 50 photos that were collected during the time the cloud was overhead show up as a dark band through the image there are probably 4 photos on each end that transition from light to dark then dark to light as the cloud begins to block the sun and then move on.

       

      Initially I was super excited about using "Match total exposures" in lightroom to solve this issue but the images dont have exfi meta tags so I used lenstagger to add meta data but after all this apparently "Match total exposures" is only useful if the actual shutter or F stop time / range changed causing a bracketed type exposure difference....It appears to be totally ineffective when the camera remains the same and the environment changes. Thoughts on this?

       

      I used "auto tone" with some success but it initially over exposes the photos and is somewhat subjective as in me having to squint and say "uhh brighter maybe"

       

      So if I have 58 photos that need to be matched to a total set of say 300 what method would provide the best results without taking up too much time??

       

      Thanks guys!

        • 1. Re: Best way: Adjusting exposure values for many images.
          Michael J. Hoffman Adobe Community Professional

          Hi GuJam,

           

          I don't know of a way to automate the process, but I can offer some suggestions to make it a bit easier.

           

          Excluding the transition photos (4 on each end) you could select the remainder that all have the same (roughly) exposure. Go to the Develop Module, and down in the lower right corner, next to "Reset," is a button marked "Sync..."

          2016-03-29_14-44-33.jpg

          Click the little toggle switch on the left side of the button, and it will change to "Auto Sync."

          2016-03-29_14-44-53.jpg

          Now, any adjustments you make to one image will be automatically applied to all 50 images, in the background.

           

          You'll still need to adjust by eye, and you'll still need to adjust the transitional images on both ends. But that's a little bit of a boost.

           

          Note: Don't forget to turn off Auto Sync when you're not using it! Otherwise you could end up adjusting bunches of images when you don't want to...

           

          Mike

          • 2. Re: Best way: Adjusting exposure values for many images.
            GuJam Level 1

            Hey thanks that helps a bit to speed things up.

             

            Im wondering if I could get better results by only adjusting exposure and doing it by hand. Bring up a base photo then compare each photo to the base photo and if its brighter or darker adjust EV a click or two...I'll have to give that a shot and see what happens.

            • 3. Re: Best way: Adjusting exposure values for many images.
              Jeff Schewe Level 5

              Actually there's an easy way to help automate making the Basic adjustments. Select a typical good exposure and make whatever adjustments are needed. Then select all the other images making sure your adjusted image is "most selected" then in the Develop module go up under the Settings menu and select the Match Total Exposures. This takes the adjusted image as the sample to match all the other images to. Works pretty well I use it a lot of doing panos.

              • 4. Re: Best way: Adjusting exposure values for many images.
                GuJam Level 1

                -Jeff

                 

                Thanks for the input!

                 

                I really really want Match total exposures to work but I cant seem to get it to do anything.

                 

                I came to the conclusion that it can only match photos that have some aspect of light metering changed (Fstop/ISO/Speed) If the enviroment changes and not the any of the camera's light metering system would Match total exposures actually adjust for dark and light images? It seems maybe it was created for bracketed images....OR maybe im just missing a something? Are you sure it will correct for environmental changes when camera settings remain the same?

                Thanks!

                • 5. Re: Best way: Adjusting exposure values for many images.
                  trshaner Adobe Community Professional & MVP

                  GuJam wrote:

                  Im wondering if I could get better results by only adjusting exposure and doing it by hand. Bring up a base photo then compare each photo to the base photo and if its brighter or darker adjust EV a click or two...I'll have to give that a shot and see what happens.

                  You can do this using the Library module Compare view and Quick Develop panel. The Exposure increments are 1.0, .33, and .17 (w/SHIFT KEY), but on my LR CC 2015 system it takes a full 1.0 seconds for the change to render onscreen.

                   

                  Using the Develop module with 'Use Graphics Processor' checked in LR Preferences there is virtually no lag when adjusting Exposure. If you see the same lag try using the Secondary display window in Compare mode with the Develop module. You don't need dual-displays to launch and use the Secondary display window. Click on the number '2' icon in the lower-left and then position and size the window so you have access to the Film Strip and Develop controls. Select the reference image and the first image to be adjusted. Make sure the image to be adjusted is "most selected' (brighter). After adjusting it CTRL-click on the next image to be adjusted and then CTRL-click the current image to deselect it. This should speed the process considerably.

                   

                  Here's an example:

                  Exposure Matching Using Secondary Display WIndow in Compare Mode.jpg