Picasa DNG Display - GH2 Long Night Exposures

Discussion in 'Image Processing' started by Boatman, Jun 2, 2011.

  1. Yesterday we had severe thunderstorms in our area. Last night on the news it was announced that a severe storm was moving though the Boston area. Knowing that I had a good vantage point on a hill near my house, I took my gear up to see if I could get some interesting distant thunderstorm shots. As it turned out, the lightening was too far away and too embedded in the clouds for any spectacular photographs, but I did gain some further knowledge of how the GH2 works in these situations and uncovered an issue with Picasa that I was not aware of. I also have realized I need to work with the camera to reduce noise in long exposures.

    A series of photographs is posted at https://picasaweb.google.com/homershannon/20116TStorms?authkey=Gv1sRgCMW8sce6r_vPtAE# . The EFX is available on the DNG files.

    It is well known that Picasa cannot properly display a GH2 RW2 file. Nor can Photoshop CS4 work with it. This file type has to be run through Adobe DNG Converter, which creates DNG files that can be displayed in Picasa and worked on in CS4. I had always assumed that the Picasa display of the DNG file was the rough equal to the Photoshop-opened file or a JPG file, if I made one. (For the thunderstorm shots I shot only in RAW.) What I discovered in the thunderstorm shots is that Picasa displays the DNG files very differently than Photoshop sees them after opening with Adobe Camera RAW. The DNG files are bright and very noisy. If fact, I nearly threw out the lot without working with them, thinking they were so bad. Fortunately, I decided to see how well Noise Ninja could clean them up before I discarded them. To my amazement, the Adobe-opened shots looked pretty decent, even without Noise Ninja. And there were other differences. In a series of shots using 16:9 format, items in the extreme edges of the photo are visible in Picasa and gone, without cropping, in CS4. (These items did not show up in the camera either, or I would have zoomed in to get them out of the frame.)

    Well, I know Picasa cannot process a GH2 RW2 file correctly. Now I know that it does not process a DNG file correctly either, even though in normal light you might not notice the difference. Hopefully Google will add the GH2-RW2 capability in a future release.

    A second issue is the noisiness of the images taken. (After processing in CS4). These shots were taken at ISO320, for the most part, and exposures ran from 1 second to 8 seconds. Five seconds seemed to be best. I've read some brief comments about stacking shorter images to avoid the noise in longer images, but in this case the short exposure images are much noisier than the exposures over 3 or 4 seconds. Other than getting a different camera, what settings, techniques or tools are recommended for improving night images?