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  1. #11
    darinwc's Avatar
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    Dont fault people for learning techniques to overcome equipment limitations.
    Thats what LF Photographers do with a large neg and movements, right?

    Some will brag about the new thing they can do but thats just people.

  2. #12

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    Quote Originally Posted by bjorke View Post


    (how it works, very roughly: if you make a blurred copy neg from a neg (use an enlarger or stat camera out of focus and 1::1 -- or make two copies, one sharp and one not), then sandwich them together, the areas where they are teh same - no detail - will be black. The areas where the blurred and focused images are different - the details - will let light through. Based on this you can start to use the mark (or its inverse) for burning and dodging.....)
    The first time I saw unsharp masking it was a technique for reducing the contrast of astronomical photographs. What you did was to make a thin slightly blurred positive from your negative, then sandwich the negative and positive together and print. What happens is that shadows on the negative are given some extra density by the positive, while highlights are not affected. This reduced the overall contrast of the negative so you can print the highlights down more without making your shadows too dark.

    Alternatively, if your negative has a normal contrast range, you can use
    unsharp masking for sharpening. Because the contrast of the sandwich is reduced, you can also choose to print on higher contrast paper which increases acutance.

  3. #13

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    Quote Originally Posted by bjorke View Post
    BTW, people (even in the digirealm) have started to catch on to the idea that wide-blur, low-intensity unsharp masking (and inverse masking) can recreate many of the tone mapping effects popular in "HDR" processing.
    This doesn't seem right to me - these techniques are only going to work if the detail is present in the original digital file. The original purpose of HDR was to work around the fact that digital sensors are only 12-16 bit devices. As such, they have a very limited dynamic range. HDR allows you to take a few frames at different exposures and combine them into a digital file that has 32-bit pixels. With 32-bits, you have much much more dynamic range. Once you have that 32-bit file, I can see how an unsharp mask techniques can then be applied to get the effects you describe.

  4. #14

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    Ultimately, I think HDR will be replaced by Digital cameras with 32-bit sensors. Since current 12-14 bit digital cameras seem to have a dynamic range of about 5 stops, I would estimate that a 32-bit sensor would have a dynamic range of 10-11 stops.

  5. #15

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    The maximum log brightness range of a print -- any print -- is at best about 2.2 - 2.3.

    How you fit the subject brightness range onto the print brightness range is part of learning to make good pictures. Use the wrong technique with the wrong subject, and the Zone System and HDR are equally crap. Do it right, with the right subject, and they're equally good.

    One difference is that more people put more effort into the ZS, working around its limitations and carefully considering the aesthetic result. With HDR, it's easier just to push the buttons and rely on the software. But there's still an awful lot of trash with both systems, because too many people regard photography as only a technical challenge, for sharper lenses or longer tonal ranges or both.

    So God isn't in either. If She exists, She is in the photographer's eye, brain or heart.
    Free Photography Information on My Website
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  6. #16
    thebanana's Avatar
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    If She exists, She is in the photographer's eye, brain or heart.
    Indeed.
    "While you're out there smashing the state, don't forget to keep a smile on your lips and a song in your heart!"

  7. #17
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    Quote Originally Posted by dslater View Post
    This doesn't seem right to me - these techniques are only going to work if the detail is present in the original digital file. The original purpose of HDR was to work around the fact that digital sensors are only 12-16 bit devices. As such, they have a very limited dynamic range. HDR allows you to take a few frames at different exposures and combine them into a digital file that has 32-bit pixels. With 32-bits, you have much much more dynamic range. Once you have that 32-bit file, I can see how an unsharp mask techniques can then be applied to get the effects you describe.
    The particular "look" of HDR images is tonal compression in the extreme areas. Thiscontext-sensitive tone-mapping requires a "deep" picture, but I see a lot of "HDR" images on flickr that are made from a single RAW file, which may in many cases have less tonal range than a color neg

    "What Would Zeus Do?"
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  8. #18

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    On the other hand it could be easier to choose a medium that won't let you record everything 'indiscriminately' - avoiding certain decisions because they have already been made for you...

    To use an analogy similar to an earlier one, companies record huge amounts of data - are all those details useful? are they useful in isolation from other details? Only if they are, or can be, analysed and interpreted in a manner that has some meaning and value to the relevant people.

    HDR is not necessarily high resolution either; nor does it need you to engage the subject any less - especially given that the current most accessible method of the technique for the enthusiast usually requires 3 exposures.

    Regarding 'fear of the world', who is the more frightened - the person who ignores the details that are present? or the person who tackles them head on? (whether or not they choose to disregard them later on)

    No art is particularly easy to master and, even if mastered, it still may not be appreciated - plus the 'reliance' on software is pretty much the same as the 'reliance' on film manufacturers or lens makers etc...

    Anyways, is god in the details? Sometimes... Sometimes not...

  9. #19

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    Quote Originally Posted by bjorke View Post
    The particular "look" of HDR images is tonal compression in the extreme areas. Thiscontext-sensitive tone-mapping requires a "deep" picture, but I see a lot of "HDR" images on flickr that are made from a single RAW file, which may in many cases have less tonal range than a color neg
    Yes - I think in many of these cases, the users do not really understand HDR. it is likely that they could achieve the same result without converting the 16-bit image data to 32-bits.

  10. #20
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    Quote Originally Posted by dslater View Post
    Ultimately, I think HDR will be replaced by Digital cameras with 32-bit sensors. Since current 12-14 bit digital cameras seem to have a dynamic range of about 5 stops, I would estimate that a 32-bit sensor would have a dynamic range of 10-11 stops.
    Bit depth has nothing to do with dynamic range. It only has to do with the number of intermediate tones between extremes.

    If a sensor can record detail over a 1000:1 brightness range (approx 10 stops), then increasing from 24 to 32 to 48 to 96 bits is not going to change the upper and lower limits of that range -- it will only change the number of intermediates.

    To get a higher dynamic range, you need a physical sensor that is responsive over a greater range of light. Once you've accomplished that, then you'll need higher bit depth to accomodate all the data -- but it's the sensor and not the bit encoding that makes this possible.

    The 32-bit files in HDR are necessary because each individual pixel holds the R/G/B information from 5, 8, 10, etc individual captures. So you need extra bit depth just to hold all that data. But it's not the bit depth per se that creates the higher dynamic range -- it's the content of that pixel information that does.
    Paul

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