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 p.1 #14 · Color management - color shift from jpg to raw | |
However,the human eyes viewing a scene are the ultimate judge of accuracy I would think.
Accuracy? No. The visual cortex is very good at adaptive seeing, making something look like you think it should look like, and it can do it instantly, even if your eyes are going back and forth between what you see on the screen and what is in front of the camera.
There are a couple of problems with your premise:
Whether or not the preview screen is calibrated and profiled independently -- kind of a moot issue actually, the facts are that at the version the camera sends to the preview screen is a processed JPEG in either a very small (sRGB) or moderately large (Adobe RGB (1998) color space, depending on how you have set up your camera for JPEG shooting, while the real world very often contains colors that are outside those limited gamuts (or color palettes if you prefer).
We also don't know whether the camera makers use relative colorimetric or perceptual rendering when doing the internal raw to JPEG processing. Without going into a long diversion about that, the choose can have a profound affect on how those out of gamut colors are brought into ("clipped") the the color space you have set your camera up to use for JPEG processing and how they make those out of gamut colors relate to the colors that are in gamut, as well as changing the relationships of the colors that are i n a truly large gamut, like ProPhoto RGB, or Lightroom's native "Melissa RGB" variant of ProPhoto RGB once they are squeezed down into the smaller color spaces.
JPEGs are 8 bit per channel, Lightroom renders raw files as 16 bit per channels -- meaning 256 (0-255) steps vs over 16,000 steps. So with a JPEG subtle and sometimes not so subtle color shade differences are lost.
While healthy human eyesight can generally distinguish somewhere in the 8 to 9 bit per channel range of color and tone -- 256 to 512 steps -- depending on the illumination level, glare, etc. those extra bits are really important when a program is processing your photo.
What the camera is sending to the preview screen (and is that initial thumbnail view) is a highly compressed JPEG being sent to the preview -- similar tones and scholar shades are lumped together.
The very smart people who write a camera's firmware and spec a camera's LCD preview screen aren't so much interested in accurate color as in what is known with good reason as pleasing color. They want what you see to naturally look good, and make you feel good about your photos (and your choice of cameras). There isn't anything wrong with a pleasing color rendition, but it is different from "accurate" color and tonal renditions.
M y advice is to treat what you see on the camera's preview screen as a rough guide, a very good polaroid test if you like, of the photograph you actually made, but not as the end all and be all of your photo.
Whether or not you care about this is up to you. They are after all your photos and you have the unassailable right to make them look any way you want them to. Unless you are unhappy with the way they look, no one can tell you are wrong. I just wanted to share with you some insight into what is going on and to clear up your misconception.
best wishes,
Ellis
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