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02/23/2007 12:54:48 PM · #1 |
Okay, this problem can only be discussed when you use RAW files in your post processing. I´m not sure though, that this is a problem, but maybe someone can comment on this, and tell me if I´m right.
When you shoot RAW footage, the camera makes two copies of the shot. One original RAW file, and one jpeg. The jpeg is a copy of the RAW file, but with compression artifacts....AND the parameters settings! In the parameter, you can set brightness/contrast/sharpness etc. The problem is, that I have a hunch that the histogram is constructed out of the JPEG file, and NOT the raw file. So the histogram can be fooling you, if you have set the parameters to the extremes.
Example: You set the brightness all the way up in parameters-settings. So the histogram will show you a properly exposed picture in the highlights, but the original raw file (which you will be working on later), is underexposed. And you´re not aware of it.
Am I right here? Is the histogram constructed from the Jpeg? And IF so, what are the best settings in parameters, to get the ´truest´ histogram, with minimal modifications?
The parameters (CANON) scale goes from -2 to +2. What is minimal modification on this scale? At ´zero´ or at ´minus 2´?
Message edited by author 2007-02-23 17:55:20. |
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02/23/2007 01:02:10 PM · #2 |
WHat are you openign the raw with?
Keep in mind Adobe Camera RAW automaticly changes the exposure, contrast, brightness (somethign else), ass sharpness and color reduction. Unless u change the preset settings.
Canon's raw converter is problky gonna give u a bette rmore accurate to cannon's spec result. Just like the noise reduction is better in Fuji's software then in camera or in Adobe.
and this -2 to +2? If thats EV then its exposure compensation if your shooting the camera with EV +2 your overexposing the shot 2 full stops... you need to shoot with the EV unchanged to get normal results i only use ev compensation if i need to make the shot over bright or dark for low key.
Message edited by author 2007-02-23 18:03:23. |
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02/23/2007 01:09:50 PM · #3 |
| I´m talking about "in-camera-histogram". The one I use to check my pictures, right after I have shot them. |
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02/23/2007 01:16:25 PM · #4 |
Originally posted by Siinji:
Am I right here? Is the histogram constructed from the Jpeg? And IF so, what are the best settings in parameters, to get the ´truest´ histogram, with minimal modifications? |
You are absolutely correct. The on-camera histogram is based on JPEG data, whether or not you're writing a JPEG file with the RAW (RAW+JPEG mode). As such, it does reflect the parameter settings, and the tendency is for the histogram to indicate clipping sooner than it should. In order for the histogram to most closely match the RAW file, you need to set your parameters for contrast and saturation relatively low. Just what is the optimum setting for your model of camera, I can't say, but it's probably near the bottom of the scale for both.
There's another way in which the (luminosity) histogram lies. It only indicates clipping when the luminosity reaches saturation. Because the different channels have different weights when calculating luminosity, the outcome is that one channel can be clipped and the luminosity histogram will not show it. That is the value of an RGB histogram; it shows the individual channels, and eliminates this source of error.
The luminosity error tends to operate in the opposite direction as the camera-parameter-induced error.
Don't be afraid to "expose to the right," but instead develop a feel for how much clipping you can recover in RAW conversion. You can nearly always recover 1/3 stop, and potentially as much as 1 stop, depending on the camera. Some converters are better at recovering highlights; ACR does a notably good job with them.
Message edited by author 2007-02-23 18:16:49. |
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02/23/2007 01:30:00 PM · #5 |
Originally posted by RainMotorsports:
Keep in mind Adobe Camera RAW automaticly changes the exposure, contrast, brightness (somethign else), ass sharpness and color reduction. Unless u change the preset settings. |
I really need to get the software with 'ass sharpness'. I think that has been my post processing problems all along! :-) |
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02/23/2007 02:33:23 PM · #6 |
Originally posted by kawesttex:
Originally posted by RainMotorsports:
Keep in mind Adobe Camera RAW automaticly changes the exposure, contrast, brightness (somethign else), ass sharpness and color reduction. Unless u change the preset settings. |
I really need to get the software with 'ass sharpness'. I think that has been my post processing problems all along! :-) |
LOL... you're not alone :-)
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02/23/2007 02:38:21 PM · #7 |
Originally posted by kawesttex:
I really need to get the software with 'ass sharpness'... |
I accidentally maxed out the ass sharpness the other day, and ruined my nice leather office chair! |
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02/23/2007 03:00:07 PM · #8 |
Just learned something.
Now I must go have a beer.
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02/23/2007 04:05:54 PM · #9 |
Originally posted by American_Horse:
Just learned something.
Now I must go have a beer. |
So you can forget it? : ) |
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