Overexposuring analog film?

Discussion in 'Digital Photography' started by Sandman, May 28, 2012.

  1. Sandman

    Sandman Guest

    In article <>,
    (Floyd L. Davidson) wrote:

    > >To determine whether you have cold/hot-spots, I could totally
    > >understand the use of a histogram, but I just can't remember seeing an
    > >image in post product and it having a problematic amount of cold/hot.
    > >Sure, it has happened, but not to the degree where I have thought that
    > >I should have had a way to determine and adjust it when I shoot it.

    >
    > An example would be taking a picture of a person's face
    > on a cloudy day, with the sky as the background. There
    > is little reason to worry about whether the sky is
    > clipping or not, as there is no detail there anyway.
    > But you wouldn't want the white parts of the person's
    > clothing to clip, nor earrings, nor teeth, nor
    > reflections off the forehead or cheeks.
    >
    > By using the blinking highlight display that can easily
    > be differentiated. Or, if one wants to avoid even the
    > cloudy sky being into clipping, the regular historam graph
    > would show that very clearly.
    >
    > Judging that by eye while looking at the image on a very
    > small LCD screen while shooting will get results scattered
    > over at least 2 and maybe 3 or 4 fstops.


    It's not like I don't trust you or anything. Usually when I shoot I
    look at the image on the LCD display and determine whether it is
    within the range of post processing usually. I.e. it may be a bit
    incorrectly exposed, but I've never been in a situation that I can
    think of where I've shot an image, looked at it and when loading it
    into Aperture it is grossly under/overexposed and beyond saving.

    Again, don't take anything of this as me questioning your methods or
    the use of a histogram :)

    > >Plus, doesn't a lot of DSLR's offer cold/hotspot flashing for images?
    > >I'm sure I've seen that.

    >
    > That is another form of histogram.


    Sure, and that type of histogram I use all the time. This way I can
    see what parts of an image is beyond saving. If none are, and the
    image looks "ok", then I feel certain that any slight exposure
    adjustments can be done in post.

    > >> If you make an exposure and the right edge of the graph
    > >> is about at the middle line along the horizontal axis
    > >> you know that the exposure could be increased by
    > >> approximately 2-1/2 stop before highlights would be
    > >> clipped. And if the graph shows a vertical line on the
    > >> far left edge, it is very clear that highlights are
    > >> clipping and exposure must be reduced if clipping is to
    > >> be avoided.

    > >
    > >SO, basically, you'd use it to see, at a glance, what your limits are
    > >for the current subject? How much of this could easily be dine in post
    > >production?

    >
    > Exposure should normally be nailed at the time the
    > shutter is released.


    Ok, but why, really? We're talking about images where the human eye
    (according to you) cannot tell by looking at the LCD whether it is
    slightly under/overexposed, yet it seems like you're suggesting that
    fixing that slight error in post is undesirable - but I'm wondering if
    it's some kind of "purist" (not meant as a derogatory term) mindset,
    or if there is some form of actual in-camera physics that I'm unaware
    of that makes 100% accurate exposure (as opposed to what, 90%?) is
    that important.

    Or is it perhaps just a desire to do ass little post as possible? That
    I could understand as well. Although - the procedure we've established
    here for using the histogram seems to be as time consuming as using
    the histogram in post :)

    > But it is also absolutely true that histograms are an
    > essential tool while processing/editing! Adjustments to
    > brightness and contrast, to saturation, and for
    > sharpening, should all be done with a very careful eye
    > on the histogram.


    Right, and here I use it *all the time*. Aperture has a very nice
    histogram display that reflects live when tweaking the image. I
    usually use it to narrow the histogram (i.e. take away the empty space
    in far left/right to enhance the clarity of the image .

    > >I.e. if the image looks ok in the LCD after I shot it, and I have
    > >hot/cold flashing to determine whether something is several
    > >under/overexposed - sure I could tweak the image within the limits in
    > >post production? I.e. what do I gain by reshooting it with a new
    > >timing in-camera at that point?

    >
    > If it is flashing to indicate clipping by "several
    > under/overexposure", it will probably make very little
    > difference what you try while post processing. Clipping
    > means the data is *gone*.


    Exactly my point. Maybe you misread. If - instead of using the
    histogram - I rely on my visual judgement and the hot/cold clipping
    in-camera to determine whether the image is "within bounds"? I am
    trying to figure out what the histogram adds to this scenario.

    > >Be sure to realize that I'm not actually *questioning* your usage of
    > >the histogram, I'm not using it myself, so I can't make any other
    > >comments than my guesses above :)

    >
    > Yes, it is quite clear that you are entertaining the
    > concept as a mental exercise, and haven't actually
    > worked with it! That is of course a good thing to do.


    Just wanted to be clear that I'm not trying to argue anything over the
    other :)

    > As I an many others who have a lot of experience with
    > this kind of technical aspect will tell you... you *do*
    > want to take it a step farther and physically work with
    > it for at least a while. You very likely will find using
    > histograms to be very very useful...


    Starting from now, I will have the histogram as my standard preview
    mode in the camera. It's a shame that my D3s doesn't support showing
    the histogram and hot/cold flashing at the same time...

    > but it is also perfectly acceptable to decide they aren't for you.
    > Different people approach the art of photography in different ways,
    > and I would like to inspire you to do what comes natural for you,
    > rather than inhibit you to what works for me! You need to explore
    > it well enough to understand exactly what it is and what it is not,
    > and then make a choice that fits you.


    Sounds about right :-D

    > Just don't pass it off as unuseful because you aren't
    > doing it now and don't understand where it would help.
    > Learn it well, then decide.


    Oh, I am most certainly *not* passing it off as unuseful

    > >> Do a web search on it, and you can spend hours reading
    > >> and learning!

    > >
    > >I just might do that :)

    >
    > Keep you busy for the rest of your life...





    --
    Sandman[.net]
     
    Sandman, May 31, 2012
    #21
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  2. Sandman

    Martin Brown Guest

    On 31/05/2012 07:59, Sandman wrote:
    > In article<>,
    > (Floyd L. Davidson) wrote:
    >
    >>>> If you make an exposure and the right edge of the graph
    >>>> is about at the middle line along the horizontal axis
    >>>> you know that the exposure could be increased by
    >>>> approximately 2-1/2 stop before highlights would be
    >>>> clipped. And if the graph shows a vertical line on the
    >>>> far left edge, it is very clear that highlights are
    >>>> clipping and exposure must be reduced if clipping is to
    >>>> be avoided.
    >>>
    >>> SO, basically, you'd use it to see, at a glance, what your limits are
    >>> for the current subject? How much of this could easily be dine in post
    >>> production?

    >>
    >> Exposure should normally be nailed at the time the
    >> shutter is released.

    >
    > Ok, but why, really? We're talking about images where the human eye
    > (according to you) cannot tell by looking at the LCD whether it is
    > slightly under/overexposed, yet it seems like you're suggesting that
    > fixing that slight error in post is undesirable - but I'm wondering if
    > it's some kind of "purist" (not meant as a derogatory term) mindset,
    > or if there is some form of actual in-camera physics that I'm unaware
    > of that makes 100% accurate exposure (as opposed to what, 90%?) is
    > that important.
    >
    > Or is it perhaps just a desire to do ass little post as possible? That
    > I could understand as well. Although - the procedure we've established
    > here for using the histogram seems to be as time consuming as using
    > the histogram in post :)


    Since the title of this thread is overexposuring (sic) analog film I
    think you should realise that for colour film there was *no* post
    processing beyond altering the final printing exposure. In a digital era
    you can digitise and rescue some quite hopeless cases.

    Slide film in particular was very unforgiving on exposure latitude so
    there was a real obsession with getting the exposure exactly right
    before pressing the shutter release. And pros would always bracket their
    most important shots to ensure one good one. Amateurs tended to feel the
    cost of materials more and were less inclined to do this.

    In a digital world provided that the image is no more than one stop
    under exposed you will lose some signal to noise and shadow detail but
    you can recover something pretty decent with a wave of a mouse.

    In the old days there was something similar in the chemistry for silver
    halide films where uranium intensifiers could be used to improve the raw
    image on seriously under exposed negative film.

    http://www.photomemorabilia.co.uk/Johnsons_of_Hendon/Johnson_Chemicals/Uranium_Intensifier.html

    It largely worked by changing the colour of the silver image from black
    to a denser red safelight colour for printing.

    --
    Regards,
    Martin Brown
     
    Martin Brown, May 31, 2012
    #22
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  3. Alan Browne <> wrote:

    > Enter the physics weenies who will now say that recording photons in a
    > quantum sense and charges is the pure essence of digital ... but that's
    > just stretching the point - esp. as the actual conversion to "digital"
    > takes place as a voltage (ADC) conversion when bucketing the information
    > off of the device).


    \begin{weenie}
    You're confusing the technical solution chosen to count electrons
    with the fact that electrons do have a fixed charge and count ---
    and that we are already counting single electrons.
    \end{weenie}

    -Wolfgang
     
    Wolfgang Weisselberg, May 31, 2012
    #23
  4. PeterN <> wrote:

    > Short and sweet, in photographers language:


    > If anything is outside the borders, it represents clipping. Try to
    > expose so that the image is as close to the right as possible,


    .... if you are prepared to change the exposure in postprocessing as
    needed (you probably don't want the black cat in the coal cellar
    to show up as light grey in the final JPEG) and are therefore
    shooting RAW ...

    > without
    > actually touching the right,


    .... unless you are overexposing parts by choice, of course ...

    > or top border.


    Top border is OK, it just means very many of that
    brightness/colour. If you're shooting the moon with a wide
    angle lens, expect to hit the top for the large amount of dark
    of the sky.

    > A D3s has the capacity to
    > display a separate histogram for each color channel, as well as for the
    > entire image.


    Most modern cameras should be able to do that.

    Note however that the histogram is of the image (usually JPEG) that
    is converted from the RAW --- not of the RAW itself. Unless you
    purposefully detune your JPEG generation with custom curves you'll
    get overexposure warnings where the RAW isn't overexposed yet
    .... so you need to interpret the histogram with your experience
    of the headroom or missing headroom.

    -Wolfgang
     
    Wolfgang Weisselberg, May 31, 2012
    #24
  5. Martin Brown <|||newspam|||@nezumi.demon.co.uk> writes:

    > Since the title of this thread is overexposuring (sic) analog film I
    > think you should realise that for colour film there was *no* post
    > processing beyond altering the final printing exposure. In a digital
    > era you can digitise and rescue some quite hopeless cases.


    And selecting paper contrast (yes, there was some variability in color
    paper contrast; though not as much as for B&W, and not as widely used).

    You can also use contrast masking to tame some of the extreme
    differentials. Again, that wasn't widely used, certainly not by
    duffers; but it was part of the toolbox of any first-rate printer (not
    me; was never a first-rate darkroom printer).

    > Slide film in particular was very unforgiving on exposure latitude so
    > there was a real obsession with getting the exposure exactly right
    > before pressing the shutter release. And pros would always bracket
    > their most important shots to ensure one good one. Amateurs tended to
    > feel the cost of materials more and were less inclined to do this.


    Also pros would sometimes do in-camera dupes, especially if shooting for
    stock.

    > In a digital world provided that the image is no more than one stop
    > under exposed you will lose some signal to noise and shadow detail but
    > you can recover something pretty decent with a wave of a mouse.


    Same was true for color negative film. (Well, wave of the control
    keypad on the video analyzer.). Or two stops, even.

    > In the old days there was something similar in the chemistry for
    > silver halide films where uranium intensifiers could be used to
    > improve the raw image on seriously under exposed negative film.
    >
    > http://www.photomemorabilia.co.uk/Johnsons_of_Hendon/Johnson_Chemicals/Uranium_Intensifier.html
    >
    > It largely worked by changing the colour of the silver image from
    > black to a denser red safelight colour for printing.


    Intensifying negatives I'm familiar with, but I'd never heard of
    "Uranium Intensifier".
    --
    David Dyer-Bennet, ; http://dd-b.net/
    Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/
    Photos: http://dd-b.net/photography/gallery/
    Dragaera: http://dragaera.info
     
    David Dyer-Bennet, Jun 1, 2012
    #25
  6. (Floyd L. Davidson) writes:

    > Sandman <> wrote:
    >>Starting from now, I will have the histogram as my standard preview
    >>mode in the camera. It's a shame that my D3s doesn't support showing
    >>the histogram and hot/cold flashing at the same time...

    >
    > Mine does... so yours probably does too! :)


    My D700 does as well, so the odds really look good there.
    --
    David Dyer-Bennet, ; http://dd-b.net/
    Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/
    Photos: http://dd-b.net/photography/gallery/
    Dragaera: http://dragaera.info
     
    David Dyer-Bennet, Jun 1, 2012
    #26
  7. Sandman

    Sandman Guest

    In article <fWFxr.15856$>,
    Martin Brown <|||newspam|||@nezumi.demon.co.uk> wrote:

    > > Or is it perhaps just a desire to do ass little post as possible? That
    > > I could understand as well. Although - the procedure we've established
    > > here for using the histogram seems to be as time consuming as using
    > > the histogram in post :)

    >
    > Since the title of this thread is overexposuring (sic) analog film I
    > think you should realise that for colour film there was *no* post
    > processing beyond altering the final printing exposure.


    Indeed. This subthread was about using the histogram view on the LCD
    of digital cameras, though. :)






    --
    Sandman[.net]
     
    Sandman, Jun 1, 2012
    #27
  8. Sandman

    Sandman Guest

    In article <>,
    (Floyd L. Davidson) wrote:

    > Sandman <> wrote:
    > >Starting from now, I will have the histogram as my standard preview
    > >mode in the camera. It's a shame that my D3s doesn't support showing
    > >the histogram and hot/cold flashing at the same time...

    >
    > Mine does... so yours probably does too! :)


    That must be a setting I haven't found yet.

    In Menu -> Play -> Display mode I have all modes turned on.
    "Highlights" is one of them (which just flashes overexposure, really),
    how do I get hot/cold in the histogram view?




    --
    Sandman[.net]
     
    Sandman, Jun 1, 2012
    #28
  9. Sandman

    Sandman Guest

    In article <2012060103175116807-savageduck1@REMOVESPAMmecom>,
    Savageduck <savageduck1@{REMOVESPAM}me.com> wrote:

    > On 2012-06-01 02:04:20 -0700, Sandman <> said:
    >
    > > In article <>,
    > > (Floyd L. Davidson) wrote:
    > >
    > >> Sandman <> wrote:
    > >>> Starting from now, I will have the histogram as my standard preview
    > >>> mode in the camera. It's a shame that my D3s doesn't support showing
    > >>> the histogram and hot/cold flashing at the same time...
    > >>
    > >> Mine does... so yours probably does too! :)

    > >
    > > That must be a setting I haven't found yet.
    > >
    > > In Menu -> Play -> Display mode I have all modes turned on.
    > > "Highlights" is one of them (which just flashes overexposure, really),
    > > how do I get hot/cold in the histogram view?

    >
    > That is my experience.
    > Nikon convention seems to be common across the pro/prosumer range when
    > it comes to display. To the best of my knowledge Nikon DSLRs do not
    > support showing flashing highlights and the histogram at the same time.
    > It is simple enough to scroll between the two display modes with the
    > front command/control wheel. as far as "hot/cold" goes, this must be
    > Floyd's or your term which Nikon certainly doesn't use. Nikon only has
    > Highlight flashing in separate displays selectable by that front
    > command/control wheel.
    > Unless of course you have chosen to reverse the front and rear wheels.
    >
    > Again, Floyd might have some additional knowledge which he might care
    > to pass on to us less aware Nikon users. Unless this is just a
    > misunderstanding & communications problem.


    Also, I don't switch between the display modes with neither the front
    or rear scroll wheel, I use the up/down d-pad to switch between them.

    And - I see now that I can get the RGB-histogram and hot-flashing at
    the same time! Not a regular histogram and hotflashing, but the
    RGB-seperated histograms (i.e. four) and then the image preview will
    hotflash.

    It's a pity, because I get a number of other useful info points in the
    regular histogram view that I don't get in the RGB histogram view


    --
    Sandman[.net]
     
    Sandman, Jun 1, 2012
    #29
  10. Sandman

    Sandman Guest

    In article <2012060104313050073-savageduck1@REMOVESPAMmecom>,
    Savageduck <savageduck1@{REMOVESPAM}me.com> wrote:

    > On 2012-06-01 03:55:41 -0700, Sandman <> said:
    >
    > > In article <2012060103175116807-savageduck1@REMOVESPAMmecom>,
    > > Savageduck <savageduck1@{REMOVESPAM}me.com> wrote:
    > >
    > >> On 2012-06-01 02:04:20 -0700, Sandman <> said:
    > >>
    > >>> In article <>,
    > >>> (Floyd L. Davidson) wrote:
    > >>>
    > >>>> Sandman <> wrote:
    > >>>>> Starting from now, I will have the histogram as my standard preview
    > >>>>> mode in the camera. It's a shame that my D3s doesn't support showing
    > >>>>> the histogram and hot/cold flashing at the same time...
    > >>>>
    > >>>> Mine does... so yours probably does too! :)
    > >>>
    > >>> That must be a setting I haven't found yet.
    > >>>
    > >>> In Menu -> Play -> Display mode I have all modes turned on.
    > >>> "Highlights" is one of them (which just flashes overexposure, really),
    > >>> how do I get hot/cold in the histogram view?
    > >>
    > >> That is my experience.
    > >> Nikon convention seems to be common across the pro/prosumer range when
    > >> it comes to display. To the best of my knowledge Nikon DSLRs do not
    > >> support showing flashing highlights and the histogram at the same time.
    > >> It is simple enough to scroll between the two display modes with the
    > >> front command/control wheel. as far as "hot/cold" goes, this must be
    > >> Floyd's or your term which Nikon certainly doesn't use. Nikon only has
    > >> Highlight flashing in separate displays selectable by that front
    > >> command/control wheel.
    > >> Unless of course you have chosen to reverse the front and rear wheels.
    > >>
    > >> Again, Floyd might have some additional knowledge which he might care
    > >> to pass on to us less aware Nikon users. Unless this is just a
    > >> misunderstanding & communications problem.

    > >
    > > Also, I don't switch between the display modes with neither the front
    > > or rear scroll wheel, I use the up/down d-pad to switch between them.

    >
    > Yup! That has always been an option. I am more comfortable using the
    > front scroll wheel. Different strokes for different folks.


    What I meant was that I *can't* use either scroll wheel, I can imagine
    the thumb wheel to be quite handy for such a thing. Another setting
    mayhaps.



    --
    Sandman[.net]
     
    Sandman, Jun 1, 2012
    #30
  11. Sandman

    Sandman Guest

    In article <>,
    (Floyd L. Davidson) wrote:

    > >And - I see now that I can get the RGB-histogram and hot-flashing at
    > >the same time! Not a regular histogram and hotflashing, but the
    > >RGB-seperated histograms (i.e. four) and then the image preview will
    > >hotflash.

    >
    > The "regular histogram" is not actually of much value,
    > it's the four RGB plus luminance display that is useful.


    Oh, I always assumed the combined was what we talked about. Sorry :)

    > >It's a pity, because I get a number of other useful info points in the
    > >regular histogram view that I don't get in the RGB histogram view

    >
    > The smaller blinking highlight display is not as useful
    > as the larger one, so if it is used as more than just an
    > indication that something is clipping (if you want to
    > know exactly what is clipping) then the full screen
    > display is more useful.


    Good point. I think I usually use highlights to see whether or not
    it's clipping, not particularly in detail what parts. The smaller
    image clearly shows how much of the sky that is clipping, but sure,
    more detail is better. DSLR's need ten inch screens soon so we can
    cram all the info we want into the display :)





    --
    Sandman[.net]
     
    Sandman, Jun 1, 2012
    #31
  12. Sandman

    Sandman Guest

    In article <2012060104512943658-savageduck1@REMOVESPAMmecom>,
    Savageduck <savageduck1@{REMOVESPAM}me.com> wrote:

    > On 2012-06-01 04:31:10 -0700, (Floyd L. Davidson) said:
    >
    > > Sandman <> wrote:
    > >> In article <2012060103175116807-savageduck1@REMOVESPAMmecom>,
    > >> Savageduck <savageduck1@{REMOVESPAM}me.com> wrote:

    > >
    > > Ignore Savageduck, he wants to hear himself talk, but has no
    > > knowledge pertaining to the discussion.

    >
    > Gee! Thanks!
    > While I appreciate the depth of your technical knowledge, particularly
    > with regard to Nikon equipment, your arrogant pomposity leaves much to
    > be desired.
    >
    > Regarding my knowledge on the subject of Nikon DSLRs, I have used them
    > exclusively since moving from film to DSLR. While I might be on the
    > lower slopes of that learning curve, or near your lofty seat at the
    > apex of that curve, I have after some 50+ years of photography
    > experience, both film and digital, learned to recognize those who I can
    > learn something from. Admittedly none of that was as a "Pro". You are
    > certainly among those I have gained from, but that has been from
    > reading some of what you have had to say, rather than through
    > interaction, or dialog with you.
    >
    > That said, from time to time I make an attempt to contribute to the
    > discussion as an active participant in these photo-groups. Folks can
    > choose to do with my contribution what they will.


    For what its worth, I appreciated your contribution to this particular
    thread. Your post made me look deeper and find out that I can indeed
    see highlighting and histograms at the same time. So, very helpful :)


    --
    Sandman[.net]
     
    Sandman, Jun 1, 2012
    #32
  13. Savageduck <savageduck1@{REMOVESPAM}me.com> writes:

    > On 2012-06-01 02:04:20 -0700, Sandman <> said:
    >
    >> In article <>,
    >> (Floyd L. Davidson) wrote:
    >>
    >>> Sandman <> wrote:
    >>>> Starting from now, I will have the histogram as my standard preview
    >>>> mode in the camera. It's a shame that my D3s doesn't support showing
    >>>> the histogram and hot/cold flashing at the same time...
    >>>
    >>> Mine does... so yours probably does too! :)

    >>
    >> That must be a setting I haven't found yet.
    >>
    >> In Menu -> Play -> Display mode I have all modes turned on.
    >> "Highlights" is one of them (which just flashes overexposure, really),
    >> how do I get hot/cold in the histogram view?

    >
    > That is my experience.


    Note he's also asking for flashing cold; I haven't seen my Nikon cameras
    (or any others) do that.

    > Nikon convention seems to be common across the pro/prosumer range when
    > it comes to display. To the best of my knowledge Nikon DSLRs do not
    > support showing flashing highlights and the histogram at the same
    > time.


    My D700 does; even in the mode where it does a small preview and four
    histograms at once (R, G, B, and l).

    But I think there was maybe a menu setting needed.
    --
    David Dyer-Bennet, ; http://dd-b.net/
    Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/
    Photos: http://dd-b.net/photography/gallery/
    Dragaera: http://dragaera.info
     
    David Dyer-Bennet, Jun 1, 2012
    #33
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