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"Exposing to the right" is over exposed, what now?
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"Exposing to the right" is over exposed, what now?
John Sheehy wrote:
Porte Rouge wrote I set my exposure to slide the histogram to the right, without clipping ( when I have time), to capture the most tonal levels . So, now when I am editing the photos they are over exposed(not clipped). A sunrise is a good example. The deep colors are washed out. The obvious fix(to me anyway) in Lightroom or CS4 is to reduce the exposure. Now my question is, by reducing exposure in post, am I just ending up in the same place (histogram to the left) as if I had just ignored the histogram when I was shooting and set the exposure to properly expose the image using my light meter? I guess in short I am asking if Lightroom or CS4 loses tonal values when you reduce exposure in editing. They're not really over-exposed, they have simply put your highlights on a tone curve which makes the colors look pale. The whole point of you "exposing to the right" is to increase the signal- to-noise ratio. The "number of tones" explanation often given is incorrect. All digital cameras have too much noise at all tones to be limited by numbers of tones, at least in the RAW data. The number of tones in your output are unrelated to the number of tones in the RAW exposure; you do not lose all you've gained when the software darkens the image. OK, the noise is more the reason but posterizing can be a problem in dark areas... raising shadows in post for the deepest shadows, and in skies where the color pallet is very limited. Doesn't the noise level follow this same principle? Or is there an unrelated reason for the noise levels paralleling tone counts? -- Paul Furman www.edgehill.net www.baynatives.com all google groups messages filtered due to spam |
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"Exposing to the right" is over exposed, what now?
Paul Furman wrote in -
september.org: OK, the noise is more the reason but posterizing can be a problem in dark areas... The only cameras I know of with even a hint of RAW posterization are the Pentax K10D, which would profit from 13 bits instead of 12 at ISO 100 (not for 200 or higher), the Sony A900 also with a need for 13 bits at base, and the D3X when in 12-bit mode. These are only on the fringe of posterizing. raising shadows in post for the deepest shadows, and in skies where the color pallet is very limited. Doesn't the noise level follow this same principle? Or is there an unrelated reason for the noise levels paralleling tone counts? Any posterization you see in a RAW conversion is most likely caused by the math used in the converter, and nothing else. Of course, JPEG compression does some posterization of its own, especially if you use too much NR and it starts blocking up. |
#4
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"Exposing to the right" is over exposed, what now?
John Sheehy wrote:
Paul Furman wrote: OK, the noise is more the reason but posterizing can be a problem in dark areas... The only cameras I know of with even a hint of RAW posterization are the Pentax K10D, which would profit from 13 bits instead of 12 at ISO 100 (not for 200 or higher), the Sony A900 also with a need for 13 bits at base, and the D3X when in 12-bit mode. These are only on the fringe of posterizing. raising shadows in post for the deepest shadows, and in skies where the color pallet is very limited. Doesn't the noise level follow this same principle? Or is there an unrelated reason for the noise levels paralleling tone counts? Any posterization you see in a RAW conversion is most likely caused by the math used in the converter, and nothing else. Of course, JPEG compression does some posterization of its own, especially if you use too much NR and it starts blocking up. OK, this makes sense, the posterizing issue is not really visible in any sort of normal exposure. What about Floyd's comment below that the noise level remains the same but exposing to the right increases the signal so that overwhelms the noise? That seems to tie the two together in a comprehensible way. The LL link just makes a lot of sense, it can't be complete BS. http://www.luminous-landscape.com/tu...se-right.shtml -- Paul Furman www.edgehill.net www.baynatives.com all google groups messages filtered due to spam |
#5
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"Exposing to the right" is over exposed, what now?
Paul Furman wrote:
John Sheehy wrote: Paul Furman wrote: OK, the noise is more the reason but posterizing can be a problem in dark areas... The only cameras I know of with even a hint of RAW posterization are the Pentax K10D, which would profit from 13 bits instead of 12 at ISO 100 (not for 200 or higher), the Sony A900 also with a need for 13 bits at base, and the D3X when in 12-bit mode. These are only on the fringe of posterizing. raising shadows in post for the deepest shadows, and in skies where the color pallet is very limited. Doesn't the noise level follow this same principle? Or is there an unrelated reason for the noise levels paralleling tone counts? Any posterization you see in a RAW conversion is most likely caused by the math used in the converter, and nothing else. Of course, JPEG compression does some posterization of its own, especially if you use too much NR and it starts blocking up. OK, this makes sense, the posterizing issue is not really visible in any sort of normal exposure. What about Floyd's comment below that the noise level remains the same but exposing to the right increases the signal so that overwhelms the noise? That seems to tie the two together in a comprehensible way. The LL link just makes a lot of sense, it can't be complete BS. http://www.luminous-landscape.com/tu...se-right.shtml That is an *excellent* article. It also has a link to another article, titled "Understanding Histograms", which several contributors to this thread could benefit from (particularly the histogram of the moon shot and the high key tree image that are the last two shown at the bottom of the article): http://www.luminous-landscape.com/tu...stograms.shtml -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
#6
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"Exposing to the right" is over exposed, what now?
Porte Rouge wrote:
On Oct 8, 6:22*am, (Floyd L. Davidson) wrote: Paul Furman wrote: John Sheehy wrote: Paul Furman wrote: OK, the noise is more the reason but posterizing can be a problem in dark areas... The only cameras I know of with even a hint of RAW posterization are the Pentax K10D, which would profit from 13 bits instead of 12 at ISO 100 (not for 200 or higher), the Sony A900 also with a need for 13 bits at base, and the D3X when in 12-bit mode. *These are only on the fringe of posterizing. raising shadows in post for the deepest shadows, and in skies where the color pallet is very limited. Doesn't the noise level follow this same principle? Or is there an unrelated reason for the noise levels paralleling tone counts? Any posterization you see in a RAW conversion is most likely caused by the math used in the converter, and nothing else. *Of course, JPEG compression does some posterization of its own, especially if you use too much NR and it starts blocking up. OK, this makes sense, the posterizing issue is not really visible in any sort of normal exposure. What about Floyd's comment below that the noise level remains the same but exposing to the right increases the signal so that overwhelms the noise? That seems to tie the two together in a comprehensible way. The LL link just makes a lot of sense, it can't be complete BS.http://www.luminous-landscape.com/tu...se-right.shtml That is an *excellent* article. *It also has a link to another article, titled "Understanding Histograms", which several contributors to this thread could benefit from (particularly the histogram of the moon shot and the high key tree image that are the last two shown at the bottom of the article): *http://www.luminous-landscape.com/tu...ng-series/unde... -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) * * * * * * Hey, that's the same article you said this about: "But regardless of that, the cited URL above from luminous-landscape is *not* full of good stuff. They miss the point entirely, and provide nothing that is actually useful!" No it is *not* the same article. -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
#7
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"Exposing to the right" is over exposed, what now?
Porte Rouge wrote:
On Oct 8, 2:36*pm, (Floyd L. Davidson) wrote: Porte Rouge wrote: On Oct 8, 6:22*am, (Floyd L. Davidson) wrote: Paul Furman wrote: John Sheehy wrote: Paul Furman wrote: OK, the noise is more the reason but posterizing can be a problem in dark areas... The only cameras I know of with even a hint of RAW posterization are the Pentax K10D, which would profit from 13 bits instead of 12 at ISO 100 (not for 200 or higher), the Sony A900 also with a need for 13 bits at base, and the D3X when in 12-bit mode. *These are only on the fringe of posterizing. raising shadows in post for the deepest shadows, and in skies where the color pallet is very limited. Doesn't the noise level follow this same principle? Or is there an unrelated reason for the noise levels paralleling tone counts? Any posterization you see in a RAW conversion is most likely caused by the math used in the converter, and nothing else. *Of course, JPEG compression does some posterization of its own, especially if you use too much NR and it starts blocking up. OK, this makes sense, the posterizing issue is not really visible in any sort of normal exposure. What about Floyd's comment below that the noise level remains the same but exposing to the right increases the signal so that overwhelms the noise? That seems to tie the two together in a comprehensible way. The LL link just makes a lot of sense, it can't be complete BS.http://www.luminous-landscape.com/tu...se-right.shtml That is an *excellent* article. *It also has a link to another article, titled "Understanding Histograms", which several contributors to this thread could benefit from (particularly the histogram of the moon shot and the high key tree image that are the last two shown at the bottom of the article): *http://www.luminous-landscape.com/tu...ng-series/unde... -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) * * * * * * Hey, that's the same article you said this about: "But regardless of that, the cited URL above from luminous-landscape is *not* full of good stuff. *They miss the point entirely, and provide nothing that is actually useful!" No it is *not* the same article. -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) * * * * * * This is the link in both of Paul's posts: http://www.luminous-landscape.com/tu...se-right.shtml The article I made that comment about is entirely different. It is by Ray Maxwell and is titled "A Possible Problem with Expose to the Right! Or Settings for an Accurate Histogram". Here is a direct quote from the article I posted, showing a distinctly different URL than the one above: " http://www.luminous-landscape.com/tu...ht-hista.shtml Wow, good stuff. I had to run out and get my camera and check the ... But regardless of that, the cited URL above from luminous-landscape is *not* full of good stuff. They" Message-ID: Date: Mon, 05 Oct 2009 17:58:51 -0800 -- Note that I am not using my usual signature on this article, because you have quoted it along with the body of text in every single exchange, which is ridiculous! |
#8
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"Exposing to the right" is over exposed, what now?
Paul Furman wrote in
: OK, this makes sense, the posterizing issue is not really visible in any sort of normal exposure. It shouldn't be visible in any kind of exposure. My comments about the limit of the value of RAW bit depth or the number of RAW levels is based on torturous tests! What about Floyd's comment below that the noise level remains the same but exposing to the right increases the signal so that overwhelms the noise? The read noise (including any dark current) stays the same, in an absolute sense. In a relative sense, it changes. For shot noise, it changes in both an absolute sense *and* a relative sense. That seems to tie the two together in a comprehensible way. The LL link just makes a lot of sense, it can't be complete BS. http://www.luminous-landscape.com/tu...se-right.shtml Well, the reasons given for the benefit are not correct. You could take one shot with normal exposure, and one with +1 EC, now using the top RAW stop, and the benefit would still be there if you quantized the top stop to 300 levels, instead of ~8000. According to my calculations and emulations, no current DSLR needs more than 300 levels for the top stop (some older models with few, large pixels may need about 325). |
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