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Thread: Image Sharpness

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    Default Image Sharpness

    My questions are: How do I determine that an image is sharp? Especially of Raw images. Camera set to neutral? How do I find the point of sharpness?

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    Frank- Do it visually, on your computer screen, while viewing the image at 100%. This latter point is crucial because at 100% no interpolation or extrapolation of pixels is occurring in software. Concentrate on image components in the plain of focus. Process is the same regardless of image source- RAW versus jpeg.

    Send a PM to Alfred Forns and he can change your name. We use real names at BPN.

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    Hi Frank
    Not a technical reply from me which I will leave to the experts like John.
    However what I do is go thro' images for clean eyeshots.
    These stand out clearly from the crowd.
    If in doubt a quick head crop with Picasa will show whether worth persevering with that image.
    Cheers: Ian Mc

  4. #4
    Alfred Forns
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    Frank John is on the money with the 100% viewing The sharpening is designed to work at that magnification.

    btw you did not say what the sharpening was going to be used for? For posting just sharpen till it looks good. I like to take them a little over so they start looking strange then back off. For printing you they need to look over sharpened.

    Also note that any sharpening in camera will not affect the raw image just he jepg. It helps when you are viewing the image on the LCD !!

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    Quote Originally Posted by Ian McHenry View Post
    Hi Frank
    Not a technical reply from me which I will leave to the experts like John.
    However what I do is go thro' images for clean eyeshots.
    These stand out clearly from the crowd.
    If in doubt a quick head crop with Picasa will show whether worth persevering with that image.
    Cheers: Ian Mc
    I'm no expert either Ian but you make a good point that a quick look at the eye for sharpness is a very good thing to check when it comes to wildlife photography or people-portraits for that matter.

  6. #6
    Dave Taylor
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    It can also help to do a selective sharpening only to the eye(s), and mask out any sharpening of detail-less areas like the sky. I believe that there used to be an issue (prior to CS3) for sharpening anything at any other view than 100 or 50 or 25 percent - it would interpolate the values so you were not actually seeing the real results unless you were at those values. This has been fixed in CS3 and CS4 though. I still agree that sharpening at either 100 for local sharpening or at 50 for more global adjustments.
    Another good point, in Lightroom. While sharpening (you have to be zoomed at 1:1 or more), if you hold down the "option" key (on a Mac), it will turn the image to a kind of gray scale, and allow you to see the areas that are being sharpened even easier. It works for all 4 variables within the Sharpening palette in LR2. Just keep holding the opt. button down as you adjust the slider. Works really slick for avoiding halos and other artifacts.

  7. #7
    Alfred Forns
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    Frank for Sharpening the easiest and most foolproof way it to use PhotoKit Sharpener. Might want to check out the website !!

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    All,
    I think Frank is asking for how to recognize when he has a sharp image. DSLR images typically are a little soft at the 100% pixel level, so it may not be obvious unless one had a reference. For example, how is a new photographer able to judge between lens sharpness, the camera's blur filter and technique? One could use the best technique and never get there because the lens is not sharp. Then different cameras have different sharpness because the blur filters are different. For example, the 5D Mark II is the sharpest I've seen out of camera, the 1D Mark II makes images that are softer at the 100% level, and on the LCD, they often look quite soft (the jpegs are softer than reality--e.g. when viewed on a computer monitor.)

    So Frank, what camera and lens are you using? Given that then maybe someone can post a 100% pixel image to show the sharpness they are getting with the same camera and lens. Then you can compare with what you are getting. Is that your problem?

    Alternatively, could people post a comparison of a perfectly sharp image, and one that is just a touch off. e.g. the pupil looks perfect in the eye versus one where the pupil is just slightly blurry. That is the standard I often use: is the pupil perfect?

  9. #9
    Axel Hildebrandt
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    I agree with Roger regarding the pupil being sharp. I only use RAW and have the in-camera sharpness quite high (1D3) since it only has an impact on the jpg I see at the screen on the back of the camera.

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