Please explain TIF And RAW

Discussion in 'Digital Photography' started by Richard DeLuca, Oct 13, 2006.

  1. Hi,

    I know you all must get asked this question many times, but I'm brand
    new to digital (but am film savvy) and don't find the answer on a quick
    perusal of the newsgroup.

    I understand that JPEGs lose information when they are manipulated, but
    what about RAW? My camera (Panasonic Lumix DMC-LX1) allows settings for
    all, but the instructions aren't very clear, at least to this newbie.

    I love darkroom work, so am going to want to fiddle with many of my
    digital images as well. I think I do understand that TIF has no
    information loss no matter how often you may make changes. Is that

    Many thanks for helping me understand!
    Richard DeLuca, Oct 13, 2006
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  2. Richard DeLuca

    Rudy Benner Guest

    Ok, I will be brave.

    What the camera sees becomes the data part of a raw file, what the camera
    thinks it should do to adjust that data is appended to the raw file as
    meta-data. If you take that same image data, and allow the camera to process
    the image the way it chooses to within the constraints of your settings and
    you do not compress the resultant file, you will have a tiff file. If you
    compress the tiff file, you will have jpeg.

    Does that help at all? I did not think so.

    Rudy Benner, Oct 13, 2006
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  3. Richard DeLuca

    minnesotti Guest

    Do a search on the Internet for "RAW". For example, you may read the
    following article, and follow the links at the very end of it,
    First, I heard of RAW, and I decided I wanted it, then I heard
    Panasonic LX1 had a good RAW capability, and I downloaded a sample RAW
    file, and I liked the manipulation with it (Silkypix, RawShooter
    Essentials, UFRaw -- don't use the Raw converter from Panasonic), and
    that was when I bought the camera. In this order. "JPEG lose the data"
    when RAW is saved as JPEG, because the file is compressed.
    All images lose information when digitally manipulated, TIFF or not.
    TIFF has a lossless compression, if this is what you mean.

    minnesotti, Oct 13, 2006
  4. RAW means unprocessed ... totally ... the color information has not been
    extracted via the interpolation algorithm. This needs to be done in
    post-processing. Most in-camera enhancements are missing from RAW files ...
    sharpening ... white balance ... contrast and so on. RAW files are
    considered as digital negatives.

    TIFF files have been processed and interpolated and can be read by many
    other utilities. The do have more information than JPGs.

    RAW is proprietary and TIFF is non-proprietory.

    Both are rather large files (compared to JPGs).

    Pros shoot RAW to allow more latitude in post-processing and they are
    willing to buy more storage and invest the time (including transferring
    Charles Schuler, Oct 13, 2006
  5. Richard DeLuca

    Roy G Guest


    RAW files are the data which is taken straight from the sensor. Nothing has
    been done to it. It needs to be converted to an image file, like Tiff or
    Jpeg or whatever, before you can make use of it. Each Camera tends to have
    its own brand of RAW files.

    There are a variety of converters available, some free, some extremely
    expensive, some allow lots of options while making the conversion and some
    don't. The ones you get with cameras tend to be rather limited.

    Tiff is a kind of image file. It is widely used, and will work in almost
    every Editing program.

    Jpeg is another one, but when editing has been done to the pixels in the
    image and then Saved, damage will be done to the image. The more
    compression applied the more damage is done, and the damage is cumulative
    for every Save, and soon becomes very obvious.

    Every time you edit any image some damage will be done.

    With Tiff that will be very slight and will not be noticed even after a lot
    of Edits and Saves.

    They are always much larger files than Jpegs, and do take up more storage
    space on your computer, but HDDs are now very large and cheap, so that is
    not much of a problem.

    If you want high quality Prints then stick to RAW and Tiff, if you are only
    working for digital display then save as Jpeg, once you have finished

    Remember to only do editing work on a Copy of your original file, so that if
    you mess up, you can always go back and start again on another copy.

    Roy G
    Roy G, Oct 13, 2006
  6. Richard DeLuca

    Ken Weitzel Guest


    In addition to all the other raw benefits, raw files are much much
    smaller than (uncompressed) tiff.

    Take care.

    Ken Weitzel, Oct 13, 2006
  7. Thank you all for the concise but understandable replies. Combined with
    the results of Googling the subject, I'm beginning to understand the
    basics of digital imaging. This is gonna be fun!

    Best Regards,

    I especially appreciate Roy's advice to only manipulate copies.
    Richard DeLuca, Oct 14, 2006
  8. Save the original image data in some format that is not "lossy".
    For example, the RAW format from your camera! You can also
    convert the data to formats like TIFF or PPM without losing

    "Only manipulate copies" means that if you are editing an image
    in any way, *do* *not* *ever* save it back over the top of your
    archived original. Final versions as well as intermediate saves
    should all go to a "working copy".

    Lossy formats (such as JPEG) should only be used for the "final"
    product, and never as an intermediate copy that you will then
    open again for more editing. JPEG makes assumptions about the
    image based on what we can actually see, and to save file space
    throws away data that does not currently have a visual impact.
    Of course if you then try to edit it again, you cannot then make
    use of the data it has discarded. On the other hand, once you
    have a *final* version, saving it to JPEG saves space on your
    hard disk.

    Along that same line, there are some common manipulations to
    images which are often applied manually that work the same way.
    "Sharpening" filters should be applied as the last step, after
    everything else has been done and in particular the size is
    fixed, because the effects vary with the size of the image and
    an appropriate amount of "sharpening" for an image reduced in
    size by half is very different than for the original.
    Floyd L. Davidson, Oct 14, 2006
  9. TIFF files make some assumptions when they format and save the file, so
    yes you do loose some information that was on the chip. This info
    primarily affects dynamic range. If you expose well, this is not much
    of a problem. It IS true that once the image is first saved, TIFF
    retains what is left.

    If what you are getting at is, "should I use TIFF as the file format
    while I am editing?" my answer is NO. Use the native file format of
    your editor- PS if you are using Photo shop, etc. These file formats
    do not compress, and retain all info also. They also retain editing
    info, such as layers and such, that tiff and other universal formats do
    Don Stauffer in Minnesota, Oct 15, 2006
  10. Richard DeLuca

    Mike Fields Guest

    One good rule to follow (you'd think I was selling disk drives)
    is to always keep the original -- make whatever you do a
    derivative of the original but with a different name. That way,
    you can always get back to where you started. (and, no,
    I have nothing to do with disk drive sales other than to
    buy them for my use)

    Mike Fields, Oct 15, 2006
  11. Richard DeLuca

    Alan Meyer Guest

    Actually Rudy, for a one paragraph explanation, I thought that
    was really good.

    Alan Meyer, Oct 15, 2006
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