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Raw files compression
#2
Hi Frank,



Why would you do this in your RAW editor? This is typically something one would do on a 16-bit processed file, a .tif or .psd, from a processed RAW.

Other than that, a bright blue sky which is fairly evenly lit may actually have very few steps going from bright blue to even brighter blue, and pulling those steps apart will make those steps show up as banding. At most, adjust the curve in RAW a little, and sharpen a little and/or add a little contrast just to undo the effect of the AA-filter, and that is really it. Save to a 16-bit file to work on.



There are two things one can do to avoid this as much as possible, or 3 if you are prepared to shoot HDR:



1) Shoot HDR

2) Underexpose the sky (a) if that is an important part of the picture, or use (strong) ND grads (<img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/cool.gif' class='bbc_emoticon' alt='B)' /> or even both

3) Always work on 16-bit files until you are completely done with processing including resizing. Only when finished convert to 8-bit jpegs or similar



1) and 2) are optional, 1) sometimes is impossible, and 2), especially (a) potentially adds noise at the lower end of the tonal scale. 3) is a must.



Other than this, personally I would always shoot lossless. Any of the other two options imply that something is lost in the recording, and that which is not recorded, cannot be retrieved at a later time.



HTH, kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....
  


Messages In This Thread
Raw files compression - by Xastoul - 05-12-2012, 04:51 PM
Raw files compression - by wim - 05-12-2012, 07:32 PM
Raw files compression - by Xastoul - 05-12-2012, 09:06 PM
Raw files compression - by wim - 05-12-2012, 10:43 PM

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