1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

HDR photography question

Discussion in 'Members' Lounge' started by 95b16coupe, Dec 1, 2008.

  1. 95b16coupe

    95b16coupe New Member

    Messages:
    6,538
    Likes Received:
    224
    Joined:
    Nov 6, 2008
    Location:
    ct
    When doing an HDR photo, why take 3 or 5 pictures when you can take 1 photo and use a computer with photoshop to under/over expose the photo? I'm trying to find some info online, but I can't get any answers.
     
  2. eg6sir

    eg6sir Supa Mod Moderator VIP

    Messages:
    21,703
    Likes Received:
    321
    Joined:
    Aug 17, 2005
    Location:
    661 BK CA
    over/underexposing doesnt give the same effect as an HDR photo..
     
  3. 95b16coupe

    95b16coupe New Member

    Messages:
    6,538
    Likes Received:
    224
    Joined:
    Nov 6, 2008
    Location:
    ct
    but isnt' manually taking 5 photos with adjusting the range going to give me the same photos and using 1 photo and adjusting 4 more versions of it? then i can combine them to make an hdr photo. i wouldn't have to worry about motion in the picture or using a tripod.
     
  4. eg6sir

    eg6sir Supa Mod Moderator VIP

    Messages:
    21,703
    Likes Received:
    321
    Joined:
    Aug 17, 2005
    Location:
    661 BK CA
    i've tried it that way... doesnt give it the same effect.. its best to take 3 pictures... hell, check out ebay.. they have tripods for under $20
     
  5. 95b16coupe

    95b16coupe New Member

    Messages:
    6,538
    Likes Received:
    224
    Joined:
    Nov 6, 2008
    Location:
    ct
    the cost of the tripod isn't a big deal. i'm just lazy and want to take several photos instead of having to setup and take 5 manually, then move on.

    i was just trying to figure out why manually adjusting the lighting with photoshop is a bad option.
     
  6. eg6sir

    eg6sir Supa Mod Moderator VIP

    Messages:
    21,703
    Likes Received:
    321
    Joined:
    Aug 17, 2005
    Location:
    661 BK CA
    try it out... you may have a better outcome than i did
     
  7. DarkHand

    DarkHand Senior Member VIP

    Messages:
    5,117
    Likes Received:
    241
    Joined:
    Sep 30, 2002
    Location:
    Chicago, IL
    Photoshop can bring out details that are already in a picture, but different-exposed photos each contain information that just doesn't exist in the others.

    My very first HDR picture ever is a perfect example:

    Think about a dark room with a brightly lit window. If you take a picture that's properly exposed for the window, you'll have an underexposed room. Photoshop can bring some of that out, but there's simply less information there than there would have been if it were exposed properly.

    [​IMG]


    Conversely, if you expose for the room, the window will be completely washed out. No amount of photoshop work can bring back what isn't there; it's simply all white.

    [​IMG]


    HDR takes the best of both worlds, combining the properly exposed room with the properly exposed window. The catch is that it needs good information to begin with.

    [​IMG]


    You can in fact 'simulate' an HDR effect by adjusting the exposure of a single image multiple times and combining them as you would separate exposures. It will look markedly different than an actual multi-exposure HDR though, since it really doesn't contain any more information than the original image did.


    That's what the 'bracketing' function of the camera is for. Hit the shutter once, and the camera automatically takes all of your exposures for you. I happened to pick a camera that didn't have bracketing (Nikon D40x) and have to do it manually, but almost all other pro-sumer level DSLRs have a bracketing function.
     

    Attached Files:

    Last edited: Dec 2, 2008
  8. 95b16coupe

    95b16coupe New Member

    Messages:
    6,538
    Likes Received:
    224
    Joined:
    Nov 6, 2008
    Location:
    ct
    i see.

    since the photo may be too dark to begin with, you can't really brighten it up because there is no data. but if it's overexposed, you will have too much "white" and wont have any data.

    so unless you can take a miraculously perfect picture, you wont be able to hdr one photo.
     
  9. reckedracing

    reckedracing TTIWWOP VIP

    Messages:
    21,056
    Likes Received:
    1,180
    Joined:
    Dec 5, 2002
    Location:
    NY
    what does hdr mean?

    Tone-mapped image made from nine exposures of Trenčín, Slovakia at night.
    [​IMG]
     
    Last edited: Dec 2, 2008
  10. eg6sir

    eg6sir Supa Mod Moderator VIP

    Messages:
    21,703
    Likes Received:
    321
    Joined:
    Aug 17, 2005
    Location:
    661 BK CA
    high dynamic range
     
  11. DarkHand

    DarkHand Senior Member VIP

    Messages:
    5,117
    Likes Received:
    241
    Joined:
    Sep 30, 2002
    Location:
    Chicago, IL
    You got it!

    Moreso than that, it's physically impossible to gather the correct amount of light with current SLR camera technology. The 'range' of the camera just isn't there. Technology exists that it can be done in a single shot, but only with special equipment in the 6-figure range. Only a matter of time before that comes down though.
     
  12. eg6sir

    eg6sir Supa Mod Moderator VIP

    Messages:
    21,703
    Likes Received:
    321
    Joined:
    Aug 17, 2005
    Location:
    661 BK CA
    that 9 photo one makes me wanna try one of those
     
  13. 95b16coupe

    95b16coupe New Member

    Messages:
    6,538
    Likes Received:
    224
    Joined:
    Nov 6, 2008
    Location:
    ct
    it helps to be good with photoshop. it's not just taking 9 pictures and layering them. that guy is definitely a professional.

    good luck and post 'em up. ^_^
     
  14. eg6sir

    eg6sir Supa Mod Moderator VIP

    Messages:
    21,703
    Likes Received:
    321
    Joined:
    Aug 17, 2005
    Location:
    661 BK CA
    photomatix does it for you.. ;)
     
  15. 95b16coupe

    95b16coupe New Member

    Messages:
    6,538
    Likes Received:
    224
    Joined:
    Nov 6, 2008
    Location:
    ct
    it only does part of it. it just layers it for you. ideally, you would adjust the lighting and color of each exposure, then layer it. or you would want to layer it, then adjust the colors manually.

    if it was just about taking 9 photos and slapping it onto photomatix, there would be a lot more hdr photos.
     
Verification:
Draft saved Draft deleted

Share This Page