Tell me again, what's the big deal about RAW images?

Discussion in 'Digital SLR' started by Norm Dresner, Jul 8, 2005.

  1. Norm Dresner

    Norm Dresner Guest

    Okay, I've finally installed Photoshop CS2 and now have a program that can
    manipulate the RAW image format from my Nikon D70.

    In a completely uncontrolled test (I'll do a formal shoot-off later) I took
    a few pictures of flowers in the garden using the RAW format for recording
    and imported them into Photoshop. At least with the Mark One Eyeball
    Sensor, I didn't see anything different than I would have expected to see if
    I had used the JPEG-Fine mode I've been using, other than files that are
    twice as big (6MB vs 3MB).

    Is there something I'm supposed to be able to do with the RAW format images
    that I can't do with the JPEGs?

    Is the resolution better?


    Norm Dresner, Jul 8, 2005
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  2. Easier to fix white balance and you avoid in-camera algorithms that might
    not always be as good as what you can do in post-processing.
    Dynamic range is better.

    Check this:

    RAW takes time and it might not be worth it in your case. It offers no huge
    advantages for most shots.
    Charles Schuler, Jul 8, 2005
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  3. Norm Dresner

    DonB Guest

    If you like to spend lots of time to get your image perfect in your
    eyes, RAW is for you. If you just want excellent images, high quality
    JPEGS are fine.
    If you showed an expert 2 different images, he would be guessing to say
    which was RAW,
    DonB, Jul 8, 2005
  4. Norm Dresner

    Pete D Guest

    Under "difficult" conditions you should probably use it though.
    Pete D, Jul 8, 2005
  5. I suggest you get and study:

    _Real World Camera Raw with Adobe Photoshop CS2_ by Bruce Fraser.

    You might want to read this also:

    It is the only way to start to work with your digital images if you
    are serious about quality.

    "I have been a witness, and these pictures are
    my testimony. The events I have recorded should
    not be forgotten and must not be repeated."

    -James Nachtwey-
    John A. Stovall, Jul 8, 2005
  6. Norm Dresner

    Owamanga Guest

    In other words, they both look as average as each other.
    Yes, correct / improve a number of aspects about them during the
    import process.
    So, you are telling me that:

    The exposure was spot on, and you didn't need to increase/decrease the
    exposure or shadows slider to give a more pleasing/stunning image.

    The color balance was perfect, and it didn't look any better slightly
    cooler or warmer than the camera's choice.

    The lens amazingly showed no vignetting that you wanted to eliminate
    or even enhance for artistic reasons.

    The saturation was spot on.

    The sharpness, luminance smoothing and color noise reduction was
    exactly correct.

    .....because, I don't believe you ;-)

    Go back, twiddle the sliders and if you still think the JPEG looks as
    good or better, switch to shooting JPEG.

    Also, be certain that you are *not* using the Nikon RAW importer
    inside Photoshop, it's junk.
    Owamanga, Jul 8, 2005
  7. I usually don't spend much more than 30 seconds (if that long)
    importing a RAW image into PhotoShop. Considering the control I have,
    the results are worth it.
    Randall Ainsworth, Jul 8, 2005
  8. Norm Dresner

    Sizer Guest

    If your picture is exactly as you want it, then jpeg is fine. But the
    jpeg is 'frozen'. The 12-bit values are white balanced, exposure
    adjusted, sharpened, saturated, etc. and then whacked down to 8-bits. Any
    changes you attempt to make to it will lower the quality of the result.

    The NEF lets you make much more dramatic changes to the picture without
    losing quality. If you accidentally screw up a great shot and have no
    easy way to go back and take the shot again the NEF gives you much more
    leeway in saving it. It's not a panacea, and the resulting picture won't
    look as good as if you'd taken the picture properly, but it'll certainly
    look better than what you could get out of the jpeg. The D-Lighting/boost
    shadow stuff is especially effective.

    Since storage is cheap now and the D70 doesn't really take any longer to
    process NEFs than JPGs I shoot everything in NEF and occasionally it
    saves me. YMMV!
    Sizer, Jul 8, 2005
  9. Norm Dresner

    Norm Dresner Guest

    You're saying that I can manipulate the color balance better in the raw
    format than I can by using levels and curves on the JPEG in Photoshop,
    Since the number of bits per pixel is the same in both, there's got to be
    something else going on then, right?

    I'm guessing but I think what you're implying is that the camera, to produce
    the JPEG, assigns binary values to the various brightness levels in a
    non-linear and non-uniform way, right?

    If that's the case, then the RAW format more closely resembles the range of
    brightness in the original image but since the number of bits per pixel is
    the same (at least think it is), then the brightness seen on the screen has
    to have the same range, doesn't it?

    Norm Dresner, Jul 9, 2005
  10. Norm Dresner

    Tom Scales Guest

    Actually the number of bits per pixel is NOT the same. RAW = 16 bits, JPEG
    = 8 bits. JPEG compresses the dynamic range dramatically.
    Tom Scales, Jul 9, 2005
  11. Norm Dresner

    McLeod Guest

    If you're comfortable with the processor in your camera making all the
    decisions on saturation, exposure, white balance, sharpening,
    luminance smoothing, and noise reduction then you should probably
    shoot jpegs and not worry about it. If you really want to learn more
    about the advantages of shooting raw you should probably download free
    from Adobe:

    There are 4 parts to the workflow article, just change the section
    numbers to get all of them.
    McLeod, Jul 9, 2005
  12. Norm Dresner

    Paul Mitchum Guest

    That's not exactly true. Most RAW file formats are 12 bits per channel
    (bpc), and typically what you'd do is import that into Photoshop as 16
    bpc, and then save as a TIFF or JPEG or whatever, at however many bpc
    you need.

    The advantage is that the difference between 12 bpc and 8 bpc isn't
    automatically lost in JPEG compression, and if you end up making a JPEG,
    you can correct for loss of dynamic range and control the compression

    Some folks might not cherish the idea of going through this process in
    order to tweak the hell out of the image this way, and for those people
    the JPEG fine setting is just that: fine.
    Paul Mitchum, Jul 9, 2005
  13. Norm Dresner

    Paul Mitchum Guest

    The resolution of the RAW file itself isn't any better or worse in terms
    of pixel count, but you can interpolate a larger image very easily
    during the import process. This enlargement will look much, much, (that
    is: *MUCH*) better than an enlargment of a JPEG.

    Lossy compression is the enemy. I wish camera manufacturers would start
    allowing their cameras to output PNG. In fact, I wish I could run linux
    on my DSLR. O-Well. :)
    Paul Mitchum, Jul 9, 2005
  14. Paul Mitchum wrote:
    Perhaps you could run Linux if your camera was built into a PDA. I'm sure
    it would be much better than any DSLR! <G>

    David J Taylor, Jul 9, 2005
  15. Tom Scales wrote:
    Not quite true - the JPEG is gamma corrected, meaning that the dynamic
    range is similar to that of the sensor, but the luminance steps in the
    JPEG are non-linear.

    David J Taylor, Jul 9, 2005
  16. Less than 2 minutes got me very good results in curves only. Yes, I
    worked on the jpeg and compression hasn't helped much, as the histogram
    shows. Without see the cup itself it's hard to know what looks best,
    but I'm not so sure RAW is a big deal for colour casts.
    Sharp Shooter, Jul 9, 2005
  17. Norm Dresner

    Andrew Haley Guest

    The colour gamut of your camera (and your Mark One Eyeball) is far
    greater than that of your PC's monitor or your printer. So, when
    displaying a digital image it's necessary to map a large colour space
    onto a smaller colour space. This process is known as colour
    rendering". (The colour spaces used in camera are usually sRGB or
    Adobe RGB. Adobe RGB is a larger space so it can record more colours,
    but it's still a lot smaller than that of the camera.)

    If you use JPEG, the colour rendering is done by your camera at the
    point of taking the photograph, without any control from you. The
    result of this can be a photograph of oranges and tomatoes that appear
    to be the same colour, because both are outside the colour gamut used
    in the JPEG. If you had used RAW, the oranges and tomatoes would have
    been recorded as being different colours, and you could have adjusted
    the image later to make them look distinct. If you use JPEG there's
    nothing you can do: the different colours have been lost.

    It might well be that you got lucky with the flowers in your garden --
    perhaps all of them were within the colour gamut of the colour space
    used in your JPEGs. But that's pretty unlikely really, as flowers are
    wildly colourful, especially in direct sunlight.

    Andrew Haley, Jul 9, 2005
  18. Norm Dresner

    Norm Dresner Guest

    These look like some very interesting documents and I'll study them before I
    ask any more questions.

    Norm Dresner, Jul 9, 2005
  19. Norm Dresner

    JPS Guest

    In message <QKAze.401133$>,
    Only if you have to change white balance, apply curves, get more
    highlights or shadows, etc.
    Technically, no, but you can get more detail sometimes if you process
    RAW makes it possible to make adjustments in one step (doing them twice
    or more increases posterization), and get more dynamic range out of the
    JPS, Jul 9, 2005
  20. Norm Dresner

    JPS Guest

    In message <_8Eze.146200$>,
    I *wish* RAW were 16 bits. It is generally 12 bits.
    JPS, Jul 9, 2005
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