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12/28/2007 09:58:29 AM · #1 |
Read a compelling argument in 'THE HDRI HANDBOOK" by Christian Bloch to the effect that even if you shoot RAW, eventually you lose information through the processing. Yet with HDRI, you never lose information. To smart for me to explain, but thought I will stimulate some discussion on the topic.
Thus, in your valued opinion, is the future of photography in HDRI and will high dynamic range imaging eventually in the future do to RAW what RAW is doing to JPEG? |
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12/28/2007 10:12:41 AM · #2 |
Not sure how to take the "even if you shoot raw, eventually you lose information through processing" bit - at least, as it relates to the question of what you gain in shooting raw versus jpeg.
With jpeg, you've thrown away data from the moment the jpeg is created. You've stripped at least 4 bits of data off the image (many cameras today are 12-bit cameras and the jpeg format only holds 8 bits). But jpeg is also a lossy compression scheme, which means it throws away data that "appears to be" redundant. Do this enough times and you seriously degrade the image.
Raw, on the other hand, captures all of the bits the sensor put out and stores them in a loss-less format. Thus, no data loss in the capture.
So comparing HDRI to Raw in that sense doesn't make sense. Assuming you shoot raw to do your HDRI they are complementary.
HDRI is simply the gathering of additional levels of exposure and tone mapping them into an image. And any amount of editing, whether done on an HDRI image or on a raw image, will result in some loss of data. Of course, if you start with a 32-bit HDRI you may be able to afford more data loss.
HDRI is somewhat limited in what it can do. You can't do an HDRI image of a soccer player, for example (or any shot of moving people or objects). So from that perspective, I also don't see HDRI replacing raw ... unless/until sensors start capturing the image in an HDR form (i.e. higher dynamic range sensors).
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12/28/2007 10:57:52 AM · #3 |
Originally posted by docpjv:
Thus, in your valued opinion, is the future of photography in HDRI and will high dynamic range imaging eventually in the future do to RAW what RAW is doing to JPEG? |
Right now, image censors, graphics cards and monitors are limited to capturing/displaying only so much data. HDRI allows us to overcome the shortommings of image sensors by combining multiple image captures to extend the amount of data.
True HDRI is simply beyond the capabilities of most display equipment so Tone mapping is employed and allows us to "cheat" and squeaze a wider range of data into an image that can be displayed on current monitors.
I think the term HDRI implies something thats it really not for in reality HDRI isnt really HIGH dynamic range it simply is a means of making images that are more true to life by overcoming limitations imposed by other technologies. High dynamic range really isnt high dymanic range when compared to what we see its only high dynamic range when compared to wat most sensors can capture.
With that in mind What I see the future holding is simply TDR or True dynamic range imaging becomming the norm. What I mean by that is sensors capable of capturing the complete spectrum of color and contrast the human eye can see. Monitors and graphics adapters that are also capable of producing and displaying true to life colors and contrast. |
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12/28/2007 11:43:05 AM · #4 |
At this point, the issue is not so much the cap0turing as it is the displaying; the sensors already capture a broader range of information than the screen (or a print) can accurately display.
For sure, the next generation of imaging will incorporate broader-range displays, as noted by others. That would be "true" HDRI. What we call "HDR" right now is just a means of processing to compress more tones into the same display-width.
R.
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12/28/2007 11:48:22 AM · #5 |
As Robert posted, all depends on the output device. Right now, 8 bits per channel is sufficient for print, and it's sufficient for most electronic display media. Until the display media demand more depth, we'll continue to use 8 bits per channel, because that produces the smallest file.
For archival use, where the image may be modified again, we want to retain all the information, and so we use higher bit depths, which right now usually implies RAW. |
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12/28/2007 11:52:01 AM · #6 |
| I think Kaveran has the right of it. I want a camera that can 'see' the scene the same as my eyes do - full detail from shadow areas to bright spots. That has nothing to do with display media and a whole lot to do with the current limitations of sensor dynamic range. That would be a very welcome technological feat. |
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12/28/2007 12:00:31 PM · #7 |
Originally posted by routerguy666:
I think Kaveran has the right of it. I want a camera that can 'see' the scene the same as my eyes do - full detail from shadow areas to bright spots. That has nothing to do with display media and a whole lot to do with the current limitations of sensor dynamic range. That would be a very welcome technological feat. |
The camera is only the half of it though. If the camera can capture it all, the display device must still be able to display the full dynamic range, and right now it cannot, so we have to tonemap to compress the data into the display's narrow range.
When we look at a scene with our eyes, we circumvent all the shortcomings of display technology, by perceiving the scene directly. |
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12/28/2007 12:52:12 PM · #8 |
| Let me rephrase then. I'd like, and hope that technology is moving towards, a camera that can capture full shadow and highlight detail in one image. Since I can take two images and expose them so that I get all shadow detail or all highlight detail, both of which my monitor is capable of displaying, it would be nice to be able to do it in one exposure. |
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