Posts Tagged ‘HDR’

Shooting HDR sets if you don’t have an AEB (Automatic Exposure Bracketing) setting on your camera

02 Nov 2011

Not every camera has an AEB (Automatic Exposure Bracketing) setting. Here’s the technique that I was using before I realized that my camera’s had an AEB setting…

You can still capture bracketed photos with any camera that has an Av (Aperture Priority), Tv (Exposure Priority), or Manual mode, and with a very small amount of practice, you can get it pretty quickly.

Here’s how to collect your set of three shots with no AEB setting:

  1. Put the Camera into AV mode
  2. Put the aperture setting somewhere in the middle (4-5.6 range)
  3. Press the shutter or shoot a shot to see what the settings are that the camera chooses for you.
  4. You will use this information to adjust your aperture in preparation for the shot.

Here’s how: Your two constraints are:

      1.  You want your slowest shutter time (brightest picture) to be no slower than 1/60th  of a second
      2.  You don’t want to run out of contrast when you have a very fast shutter speed at the limit of the camera (meaning you want a shutter speed slower than 1/1000 or 1/1600).

The adjustment is pretty easy, with a couple of rules of thumb:

      – Start with the aperture at f4.0. Shoot a test photo, or get the camera to display the settings for you (the images in the manual are too small to see whether the appropriate info displays as you shoot. If not, go into playback mode, and hit the “disp” button).
      – If the shooting time is faster than 1/400, then move your aperture to f5.6
      – If the shooting time is slower than 1/240th, move your aperture to f3.2
  • NOTE: these are my guesstimates – after you’ve shot a few “brackets”, you will get a feel for what 3 bracketed photos look like, and you can adjust manually…
      • – With the new aperture setting, shoot a test photo, or get the camera to display the settings for you.
        – You now have the info you need to take the photo. Switch into “manual” mode, and set the aperture to the number you decided upon. You will not touch aperture again for this series of shots
        – Set your timing to be (approximately) 4x as fast as the speed the camera “suggested” and displayed. i.e. if it suggested 1/200th, set it for 1/800th. If it suggested 1/250th, set it for 1/1000th.
        – Frame your photo, lining up landmarks so that you know your approximate framing. Take your first shot
        – Adjust the timing to be the suggested timing. Re-frame to line up your landmarks. Take your second shot.
        – Adjust your timing to be (approximately) ¼ the speed the camera suggested. If it suggest 1/250th, set it for 1/60th. If it suggested 1/400th, set it for 1/100th. Frame your photo, lining up landmarks so that you know your approximate framing. Take your final shot

    You now have your 3 photos (plus possibly 1 or 2 “junk” photos). Now’s when you get to use PSP to have
    some fun with them.

    Advertisements

    Creating your own HDR (High Dynamic Range) photos

    01 Nov 2011

    I’ve had a few inquiries about some photos I’ve posted to Facebook, photos like this one:
    Thailand - Islands off Phuket (HDR Image)

    The photos were shot using a technique called “High Dynamic Range” imaging (Wikipedia Article). HDR Imaging is not a new technique, but what is new is how easy it is to produce HDR images thanks to software such as  Corel’s PaintShop Pro X4.

    Quick HDR Overview:

    The concept behind HDR imaging is pretty straight forward: three shots are taken of any given scene – one at “normal” exposure, one under-exposed, and one over-exposed, and the three shots are combined to pull out details that are not visible in a typical photograph.

    Here’s an example set:

    Shot at normal exposure Shot Over-Exposed Shot Under-Exposed
    Normal
    Exposure: 1/160 sec.
    Over-Exposed
    Exposure: 1/40 sec.
    Under-Exposed
    Exposure: 1/640 sec.

    If you check out the over-exposed version of the shot, you’ll notice the extra colour that gets pulled out from the foliage, and the colour of the tiles in the pool. The under-exposed version of the same shot pulls out the details in the clouds that are washed out in the two other versions of the photo.

    Here’s what the combined photo looks like:

    High Dynamic Range version of the same scene

    High Dynamic Range version of the same scene

    You can see that the HDR version of the image shows both the details of the cloud, and the colours and details of the pool and foliage.

    So how do you create HDR images yourself?

    On the camera

    1. Check in your camera manual for a setting called “Automatic Exposure Bracketing”. If available, and not indexed separately in the camera’s manual, it will likely be listed under the Av (Aperture Priority) or Tv (Exposure Priority) sections.
    2. Follow the instructions in the manual to set up Automatic Exposure Bracketing mode.
    3. Depending upon the camera model, this may involve needing to press the shutter only once (most point ‘n shoots), or you may have to press it three separate times (more typical for D-SLR’s). Check to confirm you have 3 shots of the same image by going into “playback” mode.

    In PaintShop Pro X4

    1. Under the “file” menu, hover over “HDR” until another menu appears
    2. Select “Exposure Merge…”:
      This opens up another window in the application that is 100% focused on HDR photography. It looks like this:
      HDR Edit Mode in PaintShop Pro X4

      You now need to load up your bracketed photos into the program. To do so, click on the “+” sign near the bottom of the window, and select the bracketed photos

    3. Align your photos:
          – In the area at the left of your screen, you will see the Alignment Method is set by default to “Edge-based”. Click on “Edge-based”, and select “Feature-based” instead – it does a better job.
          – Select “Auto Crop”, then press the “Align” button
          – Once the process finishes, you should be able to select your three thumbnails at the bottom and see that the view on the main screen is now fully aligned, even if you didn’t use a tripod to do create your photo set.
    4. Remove the ghosts:
      Use the tools at the bottom to “Paint In” or “Paint Out” portions of the image, such as in the case of a moving person or vehicle in the image, or foliage blowing in the wind. I’ll let you experiment with this part, but here are a few hints:

          – when you paint something in on one of the images, you are also painting it “out” on other images
          – do your alignment before your painting, or else it will erase the painting
          – use a bigger brush for defining the areas, then correct with the “eraser”
          – don’t forget to include the shadows in the areas painted in or out!
    5. Hit the Process button to move on to the next stage of editing
    6. At this point, you can just hit the next “Process” button at the bottom of the screen, and you have a merged photo which much better displays the richness of the scene you captured. Alternatively, you can apply some of the effects available (either as presets, or as individual settings) to create a photo you find is pleasing. One thing to note: If you try some of the effects, you can always get back to the “plain” merged image by clicking on the reset button at the bottom of the left panel – but you may have to scroll down using the scroll bar to the right of the photos to make that button visible!
    7. On the final page, you get the option to “Fine-Tune” your image – with tools at the top for straightening and cropping the image, as well as some other basic image editing options. After any such adjustments, just hit “Save and close” to save your finished work.

    If you can, please let me know any areas where you hit problems, so that I can update the post for others.

    A couple of final notes:

      – The software is available as a 30 day trial here, so you can try this out at no cost!
      – If you start to shoot larger numbers of photos, you may want to consider using the “batch” mode – it will create the basic merged file for you for all of your sets of images, then you can decide which shots to revisit for further editing.

    – Enjoy –