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  1. #1
    Join Date
    Dec 2007
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    2,562

    Are all histograms the same??

    Are all histograms the same?? When I look at the histogram on my camera the exposure looks good but when I open it up in Camera Raw there are sometimes blown highlights.

    Frank
    Sony A77
    Sony A580
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    Sony 18-70 Kit Lens
    Minolta AF 35-70
    Minolta AF 50 f/1.7
    Tamron 70-300 f/4-5.6 Di LD
    Tamron 60mm Macro
    Tamron 17-50 f/2.8
    Tamron 2x Converter
    Sony HVL-F42AM
    Quantaray 70-300 4.5-5.6 Macro
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    http://www.flickr.com/photos/22083244@N06/

    http://s305.photobucket.com/albums/nn219/sparkie1263/

  2. #2
    Join Date
    Feb 2006
    Location
    Des Plaines, IL
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    The question is ...

    is the histogram after internal JPG processing of the camera? I do not think you see the RAW image on the LCD, either. I could be wrong ... I've not been that intensive in dealing with it.

    This is a question for those heroes over at Dyxum. They want to fight for the mountain top ... ask 'em.

    Damn good question, though. Thumbs up for asking, Frank.
    Last edited by DonSchap; 09-07-2010 at 06:22 PM.
    Don Schap - BFA, Digital Photography
    A Photographer Is Forever
    Look, I did not create the optical laws of the Universe ... I simply learned to deal with them.
    Remember: It is usually the GLASS, not the camera (except for moving to Full Frame), that gives you the most improvement in your photography.

    flickr & Sdi

  3. #3
    Join Date
    Dec 2007
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    2,562
    Is the image on the LCD a JPG processed image even if you are shooting RAW?

    Thanks
    Frank
    Sony A77
    Sony A580
    Sony A 100
    Maxxum 400si.
    Sony 18-70 Kit Lens
    Minolta AF 35-70
    Minolta AF 50 f/1.7
    Tamron 70-300 f/4-5.6 Di LD
    Tamron 60mm Macro
    Tamron 17-50 f/2.8
    Tamron 2x Converter
    Sony HVL-F42AM
    Quantaray 70-300 4.5-5.6 Macro
    Slingshot 200 Bag



    http://www.flickr.com/photos/22083244@N06/

    http://s305.photobucket.com/albums/nn219/sparkie1263/

  4. #4
    Join Date
    Feb 2006
    Location
    Des Plaines, IL
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    Yep ... that's the question. Local intelligence says it is a "processed" image ... but, I don't know that for certain. I did not build the thing. Great question, though ... get Dyxum involved ... see what falls out.
    Don Schap - BFA, Digital Photography
    A Photographer Is Forever
    Look, I did not create the optical laws of the Universe ... I simply learned to deal with them.
    Remember: It is usually the GLASS, not the camera (except for moving to Full Frame), that gives you the most improvement in your photography.

    flickr & Sdi

  5. #5
    Join Date
    Dec 2007
    Posts
    2,562
    I just posted it there. I will let you know what I find out.

    Thanks
    Frank
    Sony A77
    Sony A580
    Sony A 100
    Maxxum 400si.
    Sony 18-70 Kit Lens
    Minolta AF 35-70
    Minolta AF 50 f/1.7
    Tamron 70-300 f/4-5.6 Di LD
    Tamron 60mm Macro
    Tamron 17-50 f/2.8
    Tamron 2x Converter
    Sony HVL-F42AM
    Quantaray 70-300 4.5-5.6 Macro
    Slingshot 200 Bag



    http://www.flickr.com/photos/22083244@N06/

    http://s305.photobucket.com/albums/nn219/sparkie1263/

  6. #6
    Join Date
    Mar 2009
    Location
    Netherlands
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    76
    The image on the LCD is processed to JPG even in RAW so you always have a JPG on your LCD.
    You should take a few test shots to see if you have to compensate your histogram on the LCD for RAW images.

  7. #7
    Join Date
    Nov 2008
    Location
    Monmouthshire, UK
    Posts
    2,152
    S3000 is correct, the histogram that appears on the LCD is representative of a processed JPEG.
    It will alter depending on the in-camera settings you choose, for instance applying a "creative style" or changing the White Balance.
    Choosing RAW does not alter the Histogram from it's JPEG representation.

    The Histogram is most affected by the White Balance adjustment curve applied to the Sensor Data because of differing Channel sensitivities.
    For instance, say the Green channel is 1.0, it can take a linear multiplier of up to 2.5 to equalise the RED Channel.
    Because Sony (anyone) don't want accusations of blown highlights, the worst scenario, they take a conservative approach to the Histogram representation such that a scene within the camera's dynamic range will be somewhat underexposed. This is why, when we process from RAW, there is a seemingly miraculous additional 1+EV stops of headroom.

    It is possible to "fool" the camera into showing a RAW Histogram by using Uni White Balance settings. This involves neutralising any JPEG settings and choosing a WB value that results in the camera applying multipliers of 1.0 to all three channels. Because the Green Channels is the most sensitive by dint of having more green pixels (mimicking the human eye), the resultant image is heavily green tinted but at least the Histogram tells the truth.

  8. #8
    Join Date
    Dec 2007
    Posts
    2,562
    Thanks for all the detailed explanations.

    Frank
    Sony A77
    Sony A580
    Sony A 100
    Maxxum 400si.
    Sony 18-70 Kit Lens
    Minolta AF 35-70
    Minolta AF 50 f/1.7
    Tamron 70-300 f/4-5.6 Di LD
    Tamron 60mm Macro
    Tamron 17-50 f/2.8
    Tamron 2x Converter
    Sony HVL-F42AM
    Quantaray 70-300 4.5-5.6 Macro
    Slingshot 200 Bag



    http://www.flickr.com/photos/22083244@N06/

    http://s305.photobucket.com/albums/nn219/sparkie1263/

  9. #9
    Join Date
    Feb 2006
    Location
    Des Plaines, IL
    Posts
    9,560

    Red face Just some practical experimenting ...

    To further understand this ... I ran some "Quality" tests on the α700 ... RAW against JPEG Very Fine ... changing the Creative Styles, which directly affect the JPEG processing in the camera ... and regardless of whether it was in RAW or JPEG ... the LCD reflected the Creative Style selection, as Peter detailed.

    In this case, it was a very saturated Vivid +3 +3 +3 from my standard custom AdobeRGB +1 +2 -2 -1 "reduce the high-ISO noise while you are in JPEG mode" setting. (Shhh ... don't tell anyone, it'll be our secret setting for getting ISO-3200 stuff to look a lot better. This is where the α700 really excels with Creative Styles customization.)

    ::: Don waves his hand in a dismissive, Jedi-like fashion, suggesting ... "You know of no secret settings" :::

    Okay, well it worked in the movie.

    Anyway ... the LCD and resultant histogram is a JPEG interpretation ... as we all now have shared. Thank you for asking that very important question, Frank, as it truly has improved my understanding of what is a happenin' in there and I hope the readership has benefited from it.
    Last edited by DonSchap; 09-08-2010 at 06:52 AM.
    Don Schap - BFA, Digital Photography
    A Photographer Is Forever
    Look, I did not create the optical laws of the Universe ... I simply learned to deal with them.
    Remember: It is usually the GLASS, not the camera (except for moving to Full Frame), that gives you the most improvement in your photography.

    flickr & Sdi

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