1Ds Image Format Question..

Started Sep 3, 2003 | Discussions thread
Ken Phillips Forum Pro • Posts: 16,364
If it's not a TIFF ...

... then how does ANY program that can read a tiff open it? The thumbnail section definitely follows the rules ... as to the extra data, you are on your own. (Although I have code to strip it out.)
Ken

Derekasaurus Rex wrote:
Your comments about the TIFF file format are correct. I used to
think Canon was writing RAW data according to the TIFF
specification (as you mentioned was possible), but it seems they
aren't. If that's the case, why does Canon call it a TIFF at all?
They might as well put a .gif or .png suffix on it; it would be
equally misleading, would it not? I don't understand why they don't
call it a CRW, which is what it is.

Mike Fulton wrote:

Actually, TIFF absolutely is an image format, in fact the name is
an acronym for TAGGED IMAGE FILE FORMAT.

There is a very detailed specification for how TIFF files are
supposed to be put together. This specification is flexible enough
to support a wide variety of different image types. The image in a
TIFF file could be 1-bit, 4-bit, 8-bit, 16-bit, 24-bit, 48-bit,
compressed, non-compressed, JPEG-compressed, LZH-compressed,
and so forth. You can even have multiple images within the same file,
each in a different format.

In fact, the specification is flexible enough that most
applications really only support a fairly small subset of the whole
thing.

It would be possible to put raw image sensor data into a valid TIFF
file. Applications that otherwise handle TIFF wouldn't know what
the data meant, but it could still be a validly constructed TIFF
file.

But that's not what Canon is doing.

They aren't making a valid TIFF file with raw sensor data. The
".tif" files they create DO NOT follow the TIFF specification at
all. They're simply applying the ".tif" filename extension to a
file that really should have a ".crw" extension.

Mike

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