Combining exposures for increased dynamic range?

Discussion in 'Photoshop' started by Antti Heiskanen, Sep 24, 2003.

  1. I have photographed series of pictures of lit buildings and monuments.
    The contrast range in almost all pictures exceed the capabilities of
    my camera (Canon EOS 10D, but of course it would do the same on film)
    so I'm interested in combining 2 or 3 different exposures to get a
    photo with increased dynamic range (no blown out highlights or too
    dark shadows). The different exposures have naturally been taken from
    tripod and recorded in RAW-format. What is the easiest way to combine
    pictures to get publication-quality results?

    I could convert the images in Capture One to 16bit TIFFs and open them
    in Photoshop 7 to a image file with three layers, and then simply use
    eraser to remove too dark or light areas from different layers. Or
    perhaps I could use lighten/darken layer options? Or perhaps layer
    masks (but I have never used them). This all seems quite tedious so I
    wonder if there is a plugin or action that would make the task faster,
    but without compromising image quality?

    -Antti
     
    Antti Heiskanen, Sep 24, 2003
    #1
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  2. This is actually a good application for Panorama Tools, since it allows
    sub-pixel precision when matching up points from the individual images.

    I've used this myself, when taking a photo of my wife in the shade of a
    palm three, then making a second exposure that was correct for the
    brightly lit sea and sky.

    TawbaWare has a special-purpose Image Stacker that is setup to combine
    images, but I don't know if it would allow you to also compress the
    dynamic range:

    http://www.tawbaware.com/imgstack.htm

    Terje
     
    Terje Mathisen, Sep 24, 2003
    #2
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  3. I don't know exactly how to do it but there is an interesting article in
    Popular Photography (Oct. 2003) on how Photoshop was used to combine
    interior shots where the lighting was moved around. The article provides
    few details but the composite result is darned good.
     
    Charles Schuler, Sep 24, 2003
    #3
  4. Antti Heiskanen

    shaky Guest

    [snip]

    Separating a dark area from a light one with an eraser and leaving no
    telltale signs can be very tricky. The challenge is the same as making
    good selections in difficult situations. Once one can master that, many
    other editing chores become easy by comparison.
     
    shaky, Sep 24, 2003
    #4
  5. Antti Heiskanen

    Paul Furman Guest

    Here's an example that I did but I'm no pro and it ws a lot of work:
    http://www.edgehill.net/MergeSample.jpg
    Basically I took out the black from the dark exposure with the magic
    wand and pasted the remaining dark sky over the white sky. I got a nasty
    looking glow at the edge of the tree trunk and leaves that had to be
    manually smudged out.

    One thing I'm playing with here is to select a color range from the
    select menu and chose mid-tones on the dark image (pasted over the light
    one) then also from the select menu, save that selection as a Layer Mask
    (drop-down says New by default). This makes a graded mask with a more
    gradual transition and you can paint or erase to correct the mask with
    the channel active to expand or retract the mask with a fuzzy
    transparent brush. I'm just figuring this out as I write it <g>. I can
    still use the smudge on either layer or the channel.

    Using PS5.5
     
    Paul Furman, Sep 24, 2003
    #5
  6. Phil Stripling, Sep 24, 2003
    #6
  7. Antti Heiskanen

    Paul Furman Guest



    Interesting!
    I wonder if that's the same thing that can be done by setting a
    duplicate layer to screened or overlay mode? That technique works well
    with a single bad exposure but when I tried combining two different
    exposures, it turned into a muddy mess so I'm not sure this would work
    for Antti's aplication.
     
    Paul Furman, Sep 24, 2003
    #7
  8. Antti Heiskanen

    Alice Gless Guest

    Alice Gless, Sep 24, 2003
    #8
  9. Antti Heiskanen

    Paul Furman Guest

    OK I tried that in two modes: average and stack... and it didn't work
    very well. Making one of the images 50% transparent in PS has about the
    same effect. Sort of works but not real spectacular and sort of more muddy.
     
    Paul Furman, Sep 24, 2003
    #9
  10. Antti Heiskanen

    Tony Spadaro Guest

    There are several methods. I usually make a selection of the area with
    detail in one shot and paste that into the same area of the main shot. It
    doesn't take much time. You can also make differeing areas work from a
    single picture - here is a description:
    http://www.chapelhillnoir.com/mani/digi/mcompres.html
    -
    http://www.chapelhillnoir.com
    home of The Camera-ist's Manifesto
    The Improved Links Pages are at
    http://www.chapelhillnoir.com/links/mlinks00.html
    New email - Contact on the Menyou page.
     
    Tony Spadaro, Sep 24, 2003
    #10
  11. Antti Heiskanen

    Paul Furman Guest

    Summary below. Just plain old erasing!

    http://forums.dpreview.com/forums/read.asp?forum=1008&message=5992623
    " I could tell when I started to take the picture that my camera
    couldn't capture what I was seeing, and then decided to try two
    exposures. I did goof in one spot, that white pillar down the middle. I
    worked a little too fast.

    I just opened both files in PSE, did a Select All on one of them, Copy,
    then Pasted it into the other. It automatically created a new Layer when
    I pasted it in. Then set the Opacity level to about 50% and make sure
    they line up ok. Then take the eraser tool and Erase areas where I want
    the other level to show through. If the shapes are not real complicated
    to erase, it goes pretty quickly. Then change Opacity back to 100%,
    Flatten the layers and save."


    http://forums.dpreview.com/forums/read.asp?forum=1008&message=5805499
    ".. this was done using Photoshop but could be easily done in PSElements
    or a editing program that uses layers. As I said, I'm still a beginner
    using Photoshop. All I did was created 4 layers

    -- 1. for the background which included the building and sky;
    -- 2 for the colored clothing and trees -- this became the main layer
    -- 3 for white aprons

    -- 4 for the faces (exposing for the faces meant a levels adjustment
    that would blow out all of whites and background.)

    Using the eraser tool, I just removed those portion of the layer that
    weren't needed and then merged the layers. Simple, labor intensive but
    effective."
     
    Paul Furman, Sep 24, 2003
    #11
  12. Click!
    http://robertdfeinman.com/tips/tip1.html
     
    /\\BratMan/\\, Sep 24, 2003
    #12
  13. Antti Heiskanen

    ZZ Guest

    ZZ, Sep 24, 2003
    #13
  14. Antti Heiskanen

    Jim B. Guest

    I believe there are a couple of methods outlined at a website called
    luminous landscape that give step by step directions to merge two exposures,
    one for highlights and one for shadows. The methods work exceptionally
    well. Sorry I cant remember the exact name of the website, but it is fairly
    well known to the photography crowd. You may wish to look there.

    Jim
     
    Jim B., Sep 25, 2003
    #14
  15. I think this is the site you're talking about:

    http://luminous-landscape.com/tutorials/blended_exposures.shtml

    I'm not sure it answers the original question, though...
     
    Robert A. Barr, Sep 25, 2003
    #15
  16. Antti Heiskanen

    Tony Spadaro Guest

    Tony Spadaro, Sep 25, 2003
    #16
  17. Antti Heiskanen

    Paul Furman Guest


    Hmm, that points to someone who automated the thing with an "action" but
    their site says it's unavailable and will be replaced with a plugin
    soon. I wonder how they automated it. All the other techniques are manual.

    hmmm...

    Ah ha!

    OK, this is taken from another recently mentioned tutorial:
    I've put it together on this page
    http://www.edgehill.net/overlay
    but will keep the text here if you don't want to load up all the images.
    (it's an ugly picture but was very challenging, including strong
    contrasts and out of place contrasts also)

    1. Match up the images with the dark one on the top layer.

    2. Copy the light image into a new file and convert it to greyscale.

    3. Back in the composite drawing, load a selection from the temporary
    file (select menu - load). It will show with the marching ants in a
    simplified form but is actually a greyscale selection than can be made
    into a channel mask in the next step.

    4. Set the dark image layer current and from the select menu, save the
    selection as a channel mask by pulling down "new" and chosing "dark
    mask". Deselect to get rid of the ants and it's done.

    5. There are some odd muting effects though. Turn on the new mask
    channel to see the grayscale selection in red. There may be odd places
    within the dark area with natural highlights that have been muted
    unnaturally with a weird halo at their edges.

    6. Turn off the dark layer to see them and correct them by setting the
    mask current and using the smudge tool to bring a similar level of
    masking to these spots, to bring the highlights back. Turn the mask off
    to see the results. You can use the paintbrush and eraser with varying
    levels of opacity to match but that's difficult. At some point you may
    find yourself repainting the whole thing at which point there was no use
    in the shortcut. Better results can be had by doing it manually but it's
    a lot of work that way.
     
    Paul Furman, Sep 25, 2003
    #17
  18. Yeah, this is exactly the technique I use, except that I use PanoTools
    to convert the dual (or more) images into a single masked multi-layer
    PSD file.

    This avoids all the need for manual adjustments to get perfect
    registration between images, and as an added benefit, it also corrects
    for lens abberations.

    Terje
     
    Terje Mathisen, Sep 25, 2003
    #18
  19. Antti Heiskanen

    Jim B. Guest

    Jim B., Sep 25, 2003
    #19
  20. Antti Heiskanen

    geoff murray Guest

    The easiest way of all is to purchase Fred Miranda's action called Dynamic
    Range Improver. Very quick and easy with excellent results.

    Geoff
     
    geoff murray, Sep 26, 2003
    #20
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