1 Reply Latest reply on Nov 25, 2009 11:36 PM by Mylenium

    Any way to gradually adjust exposure change?

    Rashomon19

      I make time lapses and there is a very common frustration where flicker is created by small exposure changes due to the aperture blades not falling in the same position or when using an auto mode where exposure changes and the camera changes exposure values.  To problem is worsened when doing a time lapse during sunset/sunrise when one expects the exposure to change drastically but needs to compensate in order to get the entire scene.

       

      I've experimented with using Lightroom's "Match Total Exposures" feature which is great at adjusting the exposure to even out the discrepancies between changing exposure values.  But this doesn't take into account the exposure of the scene is expected to change.  So when doing this for a sunset, as I increase the shutter speed to account for the setting sun, Match Total Exposures adds negative EV because it recognizes the longer shutter speed would be over exposing the selected "correct" photograph.

       

      I would very much like to find a way to use the Match Total Exposures feature to first even out the exposure changes from the changing parameters, and then apply a batch gradual exposure change to the series in After Effects to create a time lapse sequence so that it will know to allow for these changing lighting conditions.

       

      But to do this, because I would need to export the photos from Lightroom, either the beginning or the end (depending on which photo I selected to be my optimum lighting condition for the "Match Total Exposures" feature) will be dramatically under or overexposed.  By saving as RAW or 16-bit Tiff would I be able to preserve the dynamic range so when I bring it into After Effects I will be able to recover to the correct exposure values without loosing image quality?

        • 1. Re: Any way to gradually adjust exposure change?
          Mylenium Most Valuable Participant

          http://www.gbtimelapse.com/

           

          Not only would it make sense to get their plug-in but also to read up their theoretical blurb (which is quite good in covering the facts). Regarding "retaining quality" you may also wish to explore Photoshop's Merge to HDR to create an averaged reference image out of 3 or 5 images. While it may produce ghosting here and there, it could serve to create a smoother version which you then could subtly overlay over your other footage to reduce flicker. The rest is pretty much a moot point - even a 12bit/ 14bit RAW file can only contain so much info, so if your exposure is completely off, all the filters in the world cannot bring it back. Also note, that there is no need to convert unprocessed RAW files to anything else - AE can open many of them natively with its own version of Adobe Camera Raw, though it lags behind ACR/ Lightroom with format support....

           

          Mylenium