"Jufi" <bowser@[EMAIL PROTECTED]
> wrote:
>"Alienjones" <Alienjones@[EMAIL PROTECTED]
> wrote:
>> Nearly all RAW files are nothing more or less than TIFF files. There is
>> no such thing as raw sensor data in a camera RAW file.
>
>doesn't make sense... TIFF files cannot have their WB adjusted like RAW
>files.
An image saved in an TIFF image format can have it's WB
adjusted. Perhaps not as dramatically as could be done
using the raw sensor data, but...
However, RAW files are TIFF files only in the sense that
they use the standard file format to locate data in the
file. They do *not* use the same data format to express
the image. The TIFF image format is an RGB format, and
RAW files are not.
What that means is a program to read a RAW file can use
a "standard" method of finding various component data in
the file. That simplifies coding a program greatly.
But the ****tion of the program that processes the sensor
data in RAW files is *nothing* like the code that would
be used to display a TIFF image.
It's sort of what would happen if you built a really
nice set of shelves in a closet, and your brother/sister
looked at them and realized just how good they are, so
he/she builds a closet with similar shelves. But one
closet is for men's clothing and the other is for
women's clothing. (Or one is for food and the other is
for children's toys, etc etc.)
Same TIFF shelves, but different data formats.
>> Where the basic difference in white balance is... The RAW file contains
>> information known as camera settings which the picture you see on your
>> screen when you look at a RAW file is composed from.
>
>Yes, I know the RAW file contains the "as shot" info, but does that
affect
>the image? I doubt it.
It might, it might not. Some software is designed and
intended to reproduce exactly what the camera produces
(as a default). Other software is not.
>> You have the choice of altering this original camera information when
>> you edit a raw file, something that is only marginally available when
an
>> image is developed and compressed into a JPEG.
>
>Exactly, the only parameters that have been APPLIED to a RAW file are
focus
>and exposure. There's lots of other info attached, but that's all it is.
There can be, and with some cameras there definitely is,
a great deal more processing applied to sensor data
before is is saved to the RAW file than just light
values. There are some cameras that do White Balance
adjustments at the analog level, and some that appear to
do at various kinds of noise reduction at that level.
There is little doubt that some cameras do significant
processing after digitization, even to RAW data. It is
exceedingly difficult to determine exactly what is or is
not being done because companies are keeping that
information secret. (If Nikon or Canon can cause
customers to believe their camera produces better color
or less noise, they *don't* want to tell the other
company how they did it. Once it all becomes well known
and every camera has it, then all of them will be very
happy to tell us how their implementation is better than
the other guy's. But not yet...)
>> There has been a lot of wrongful presumptions made about JPEG images by
>> many people I would have thought might have had a clue but don't.
>>
>> Those cameras which allow you to select uncompressed JPEG as a save
>> option, produce remarkable clear and stunning photos... Provided you
>> have enough skill to get it right in the camera. A lot of people from
>> the film camera era have that ability.
>>
>> As for RAW being the panacea to do everything? Uh, uh. You'll be sorry
>> to hear this but Rita is right. White balance is a fundamental
>> requirement for correct exposure.
>
>But it's not applied to the RAW file, is ;it?
WB can be done on the analog data from the sensor, which
will result in improved dynamic range over WB
manipulation done on the digitized data. It appears
that Nikon's high end cameras do that (Nikon has as much
as said they do), and it is very likely that others do
to. But because it produces results with differentiate
brands, none of them are will to give details about how
or what they do.
>> All you get in RAW files is the ability to choose a different WB, you
>> can do that with a correctly exposed JPEG in many RAW editors too, if
>> you want to degrade the the picture or give it a colour cast.
>>
>> Nest time you do some photography, shoot raw + JPEG and compare the
>> results. You might be surprised how few times you do actually get it
>> right in the camera.
I shoot RAW+JPEG using Nikon cameras. I set the JPEG to
the least possible processing to prevent the JPEG
settings from affecting the camera's exposure
metering/indicating system. The JPEG settings affect
the blink on over exposure display and they affect the
histogram, as well as the exposure meter. I want only a
quickly available JPEG proof, not a final product, and
certainly do not want the production of that proof to
interfere with getting properly exposed images.
--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@[EMAIL PROTECTED]
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