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Please explain TIF And RAW

 
 
Richard DeLuca
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      10-13-2006
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
correct??

Many thanks for helping me understand!
Rich
 
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Rudy Benner
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      10-13-2006

"Richard DeLuca" <(E-Mail Removed)> wrote in message
news(E-Mail Removed)...
> 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
> correct??
>
> Many thanks for helping me understand!
> Rich


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.

r.


 
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minnesotti
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      10-13-2006

Richard DeLuca wrote:
> 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.


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,
http://en.wikipedia.org/wiki/RAW_image_format

> 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.


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.

> 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
> correct??


All images lose information when digitally manipulated, TIFF or not.
TIFF has a lossless compression, if this is what you mean.

...

>
> Many thanks for helping me understand!
> Rich


 
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Charles Schuler
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      10-13-2006
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
images).



 
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Roy G
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      10-13-2006

"Richard DeLuca" <(E-Mail Removed)> wrote in message
news(E-Mail Removed)...
> 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
> correct??
>
> Many thanks for helping me understand!
> Rich



Hi.

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
editing.

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


 
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Ken Weitzel
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Posts: n/a
 
      10-13-2006
Charles Schuler wrote:
> 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
> images).


Hi...

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

Take care.

Ken

 
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Richard DeLuca
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Posts: n/a
 
      10-14-2006
In article <(E-Mail Removed)>,
Richard DeLuca <(E-Mail Removed)> wrote:

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,
Rich

PS:
I especially appreciate Roy's advice to only manipulate copies.
 
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Floyd L. Davidson
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Posts: n/a
 
      10-14-2006
Richard DeLuca <(E-Mail Removed)> wrote:
>PS:
>I especially appreciate Roy's advice to only manipulate copies.


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
information.

"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 <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) http://www.velocityreviews.com/forums/(E-Mail Removed)
 
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Don Stauffer in Minnesota
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Posts: n/a
 
      10-15-2006

Richard DeLuca wrote:
> 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
> correct??
>
> Many thanks for helping me understand!
> Rich


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
not.

 
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Mike Fields
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Posts: n/a
 
      10-15-2006

"Don Stauffer in Minnesota" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) oups.com...
>
> Richard DeLuca wrote:
>> 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
>> correct??
>>
>> Many thanks for helping me understand!
>> Rich

>
> 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
> not.



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)

mikey

 
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