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  1. #1
    Junior Member
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    Dec 2007
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    Rochester, MN, USA
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    38

    Help please.....

    Playing with RAW images, and using the Sony software that came with my Alpha, and now I'm confoozled...

    How the hell do I use

    1. EV-don't even completely understand what it is???
    2. White balance-kinda understand, but this one has color temp, color correction, and specify a gray point?????
    3. Hue-understand basically, but need to know interactions with other options..
    4. Saturation-I think I got this one down.
    5. Sharpness-when would NOT want a pic to be sharp???
    6. Noise Reduction- Again, when would you NOT use it??
    7. Contrast- I think I understand this one, but would like to know how it interacts
    8. Tone Curve- When would you mess with this??

    Sorry for the multiple questions, but trying to play with some RAW images, and the menu comes up with all of these options, and I'm just not sure what to do...

    Kinda overwhelmed...

    Thanks for all of your patience...
    SIC VIS PACEM PARA BELLUM

    "No matter whether a person belongs to the upper or lower ranks, if he has not put his life on the line at least once, he has cause for shame" Nabeshima Naoshige (1538-1618, A.D.)

  2. #2
    Senior Member Medley's Avatar
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    Nov 2006
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    Hillsboro, OR, USA
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    919

    Re: Help please.....

    Not familiar with the Sony software, but these adjustments are rather generic for Raw converters, so here goes:

    Quote Originally Posted by physasst
    1. EV-don't even completely understand what it is???
    EV stands for Exposure Value. As you probably already know, the aperture, shutter speed, and ISO settings for an image combine to determine it's exposure. Occasionally, the image will come out too dark (underexposed) or too light (overexposed). When you shoot in Raw mode, the exposure is recorded, but is not "locked in". This adjustment allows you to adjust the overall lightness or darkness of the image, within certain limits. It is generally one of the most-used adjustments (at least in my case ).

    Quote Originally Posted by physasst
    2. White balance-kinda understand, but this one has color temp, color correction, and specify a gray point?????
    Color Temp.- I'm sure you've heard of "warm lighting" and "cool lighting". this refers to the color temperature, and is measured in degrees Kelvin. Warm lighting gives off a yellow glow, and gives a yellowish tint to all objects in the room. Cool lighting, on the other hand, emits a bluish tone. Think of either of these hitting a white object, and you can envision how they the lighting can alter what the camera "sees" as being the color white. This adjustment compensates for the lighting, which is what White Balance is all about.

    Color Correction- Not having any direct knowledge of the software, I can't give much practical advice here.

    Specify a Grey Point- If you know how to go about it, this is an extremely helpful adjustment, but it requires some forethought in shooting your images. Many dealers sell "grey cards", which are simply cards of a specific shade of grey (though sometimes, more than one shade). So for any given lighting condition, your first shot is a shot of the grey card (for best results, the grey card should fill the image). Then proceed with the rest of your shots. The theory is that you KNOW what color the grey card should be, and any following images should be "off" by the same amount as the grey card image, SO LONG AS THE LIGHTING HASN'T CHANGED. That's important. If the lighting changes (you go to a different room, etc...), simply re-shoot the grey card. Then, when you edit them with your software, you should be able to select all the images in a group, point to the grey card, and say "This is how we define "grey" for all these images. Bingo, White balance accomplished.

    One last caveat to this is that the "define greypoint" tool has to be defining the same grey as the card. The are any number of shades of grey between white and black. Most software denotes them as some percentage. For example, 50% grey is halfway between white and black, while 60% grey is a bit darker. In Photoshop, you can double-click a greypoint "eyedropper" to define what you mean by "grey". You should have some way to adjust it in your software also.

    Quote Originally Posted by physasst
    3. Hue-understand basically, but need to know interactions with other options..
    4. Saturation-I think I got this one down.
    The Hue and Saturation tools I generally don't mess with much in the Raw converter. It's mostly useful in calibrating a camera where precise color matching is necessary. The problem is, if you change lighting conditions, you throw everything out of balance. So it's really only useful under controlled lighting conditions, such as a studio.

    Quote Originally Posted by physasst
    5. Sharpness-when would NOT want a pic to be sharp???
    6. Noise Reduction- Again, when would you NOT use it??
    I've grouped these two together because they interact with one another. In reality, they're pretty much polar opposites. Applying sharpening across the entire image enhances the noise, making it more apparent. Conversely, applying noise reduction across the whole image not only blurs out the noise, but applies the same blur to the edges of the image, softening it. The solution is to apply sharpening and noise reduction to specific parts of the image, but that is generally not easily done in most Raw converters. Most adjustments are applied globally (to the whole image).

    The proper question is not "When would you not want an image to be sharp?" but "At what point should I sharpen the image?". Conventional wisdom says that an image should be sharpened once, and only once. And unless you REALLY know what you're doing, that's very, very good advice. Most people will probably tell you that sharpening is one of the last things that they do. So really, the question becomes "How much editing am I going to do to this image?" If the images are going to straight from the camera to the printer, then the sharpening options on your camera are the best place to apply sharpening. If your going to print them straight from the Raw converter, then the Raw converter is the best place. And if you're going to edit them in some other application, such as Photoshop or Photoshop Elements, then THAT is probably the best place to do your sharpening.

    Noise reduction works on the same basic principles, but noise can be camera-specific, and a certain amount of noise reduction here can help significantly, if you go about it correctly.

    Quote Originally Posted by physasst
    7. Contrast- I think I understand this one, but would like to know how it interacts
    The biggest interaction here is going to be on sharpening and noise. Sharpening a digital image entails increasing the contrast to a specific part of the image- the edges. Increasing the contrast after sharpening increases the contrast to the entire image, adding even more contrast to the edges. Since noise is essentially the same as the image edges- pixels of different contrasts next to one another- increasing the contrast will probably make the noise more visible as well. To minimize this, I generally make contrast adjustments early on, usually right after the Exposure adjustment. Keep an eye on image sharpness and noise to see how they're affected.

    Quote Originally Posted by physasst
    8. Tone Curve- When would you mess with this??
    Generally speaking, I don't- at least not here. Again, a lot depends on how much editing you're going to do AFTER this. The tone curve can be handy for making adjustments to some parts if the image, while leaving the rest unchanged. For example, if you have some trees in the background that came out very dark, and you want to lighten them without changing the contrast of the whole image, it could be done with the Tonal Curve. You can also use it for more specific Contrast adjustments, affecting JUST the light or dark pixels, for example. Once you learn how to use it, it can be helpful for correcting specific problems.

    If you have questions (and I'd be really surprised if you don't, ), fire away. I'll answer them as best I can.

    Hope this helps you some.

    - Joe U.
    I have no intention of tiptoeing through life only to arrive safely at death.

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