Absolutely all cameras produce these jpeg because it's the only way they
have to display the picture on the rear screen. The only difference is
that the resolution and compression settings differ from one
manufacturer to another.
Canon: Full resolution - compressed jpeg.
Fujifilm: reduced resolution - compression?
Nikon: Full resolution - jpeg slightly compressed (~ 80%)
Other brands:... (you must complete the list; -))
JP
Le 09/11/2017 à 15:23, Remco Viëtor a écrit :
On jeudi 9 novembre 2017 13:36:32 CET Ole Barnkob Kaas wrote:
As a side note Canon (at least on my 7D M2) saves a “thumbnail” inside the
RAW photo and can easily be extracted with e.g. exiftool.
The “thumbnail” is a full resolution JPG with corrections. So theres
actually no need to shoot RAW+JPG - if you know how to excel with exiftool.
It would be nice if you could disable this feature as it eats bandwith when
writing from buffer to CF-card. If you really need to shoot 10 pics/sec for
longer time.
Downside is that you have no quick way to see what's in the raw file. The
embedded preview is what's used by most viewers to display an image for a raw
file. As those don't have a demosaicing option build in, they wouldn't be able
to show a preview of a raw w/o embedded jpeg.
Also, a lot of cameras store half-resolution jpegs as embedded jpegs (afaik).
While those might have more than enough pixels for a screen display, for
printing they might be too small.
Remco
P.S. As a half-resolution image from a raw file does not require
interpolation, it's also very fast to generate: red and blue pixels can be
used 'as is', for the greens, you can average them, or just use 1. Of course,
you'll still have to at least apply white balance, white and black points and
a gamma transformation.
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