Why use HDR?

Discussion in 'General Gallery' started by chakalakasp, Aug 22, 2006.

  1. chakalakasp

    chakalakasp TPF Noob!

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    Here's an interesting comparison of the same scene shot with two photographic methods. The first was shot traditionally, metering for the sky. The second was shot using HDR, a photographic technique that involves tripoding the camera and taking photographs of the same scene again and again at different shutter speeds (to capture as much dynamic range -- light values -- as possible) and then combining them with an algorithm (I use Photoshop's). Once combined, you tone the photo as you normally would. The strength of HDR is that it allows the photographer to capture a wide range of light values without using gradiated filters. It actually beats filters handily, as filters are nowhere near as detailed in their masking as an algorithm can be. So, #1, normal, #2 HDR,

    #1
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    #2
    [​IMG]

    This was a shot of the NYC skyline at sunrise. Sunrise behind buildings is a great candidate for HDR, as light of the sky is so much brighter than the light on the face of the buildings, as the light hitting the face of the buildings is only the light that refracts in the atmosphere and reflects off of the surrounding terrain. However, our eyes and brains are sensitive and smart enough to still resolve color and detail on the buildings while resolving the detail in the sky, too -- but our cameras our not. Well, not without a little help. :)
     
  2. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    I don't like the sky in the 2nd one, compared to the first.

    For something like this, two exposures is really all you need. One for the sky and one for the foreground (city).
     
  3. DeepSpring

    DeepSpring TPF Noob!

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    Is something like this the digital equivalent of exposing a frame several times on film?
     
  4. Arch

    Arch Damn You! Staff Member Supporting Member

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    For HDR you need as many exposures as possible....... its not to be confused with photo merging (of two exposures)....... the more tonal values the HDR method uses the better......

    However in my experience it can give too many midtones and make an image look a little flat..... so i do agree the sky is better in the first..... its an interesting result to be able to see the city detail in this type of shot tho, i just prefer to use HDR to be able to show detail in shadows if i choose to expose it, rather than filling the scene with mid tones.
     
  5. chakalakasp

    chakalakasp TPF Noob!

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    Putting contrast back in the sky is extremely easy; I just chose not to (it looks more impressionistic that way). I think the reason we want contrast so much is that that's what we're accustomed to seeing in photography. Anything with lack of contrast is deemed flat, even if the flatness is caused by a very smooth and nuanced rendition of colors.

    It's true that this photo could have (with a whole lot of work) been done with just two exposure and a zonal merge, but it would not have retained nearly as much tonal and color detail as is evident in the full photo. Honestly, if you're going to photomerge, you may as well just save the trouble and spring for a gradiated filter.
     
  6. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    That's what I meant to say...that merging two photos would have looked better than using the HDR function in Photoshop. In this case anyway.

    I don't have CS2, so I've never tried HDR...but I have been able to create an image with a high dynamic range, simply by merging photos and using layer masks. This method allows me a lot of control but it can be time consuming.
     
  7. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    It's shots like this, that make me not want to use a graduated or split filter. The horizon is very rarely flat and even...it's often erratic like in this city scape. I prefer the results of merging & masking to the 'compromise' that is achieved with the filter.
     
  8. mschoelen

    mschoelen TPF Noob!

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    I tend to like sillhoettes (sp) better.
     
  9. Tiberius

    Tiberius TPF Noob!

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    HDR certainly isn't for "every" shot, and it's obviously not for sillhouettes. It's a great tool for a wide variety of shots, however.
     
  10. THORHAMMER

    THORHAMMER TPF Noob!

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    its not a bad outcome,

    but I personally stray away from HDR myself I enjoy using the strengths of each landscape in each shot, I personally would rather see the sky in all its beauty , or the cityscape in its beauty and have the sky blown out..(and possibly cropped out too ) Most of the HDR shots I have seen look really bad compared to the orininals, expect for some reason interior architectural shots look really awsome with the right lighting and HDR

    Its sort of a zen philosphy I apply to photos.

    Just to me Id rather have 100% of the beauty of one particular thing ie,
    sky, foreground, etc..... then spread myself too thin.

    On certain shots you can definately adjust both to look pretty decent,
    but I think it takes away from the intensity of the emotion you want to invoke,

    of course commercial shots are another story, then you have to compromise many times....
     

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