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Difference between Focus, Sharpen, and Unsharp Mask?
- Thread starter jsteph
- Start date
At pixel level, I recall what a "sharpen tool" does, is basically exaggerating the boundary between neighboring groups of similar pixel. e.g. when a light-gray group meets a dark-gray group (hence somewhat 'blurred'), tool does two things at the boundary: (1) paint a line of black pixel within the light gray region, (2) paint a line of white pixel within the dark gray region. The overall result then looks 'sharpened' along the boundary.
Quite logically, for colored regions, sharpen tools would play around the Color Wheel, looking for complementary colors to exaggerate differences.
This is what 'Sharpen filter' or 'Sharpen tool' does.
This also means if the tools overdo its task, an unwelcomed line of 'outerglow' occur at the boundary.
That's why the Unsharp Mask. It offers user-definable parameters, like (i) the amount of exaggeration, (ii) the radius of operation & (iii) the threshold used for 'grouping similar regions'.
If (i) is the only desired correction, i think a handy alternative is to use Edit->Fade Sharpen, IMMEDIATELY after using a Sharpen Filter. It offer a wider choice 'what amount of overdone exaggeration' you want to undo. (luminosity is my favorite choice).
Is 'focus' another feature of Photoshop. No idea, seldom use it, eagle to learn if yes.
Quite logically, for colored regions, sharpen tools would play around the Color Wheel, looking for complementary colors to exaggerate differences.
This is what 'Sharpen filter' or 'Sharpen tool' does.
This also means if the tools overdo its task, an unwelcomed line of 'outerglow' occur at the boundary.
That's why the Unsharp Mask. It offers user-definable parameters, like (i) the amount of exaggeration, (ii) the radius of operation & (iii) the threshold used for 'grouping similar regions'.
If (i) is the only desired correction, i think a handy alternative is to use Edit->Fade Sharpen, IMMEDIATELY after using a Sharpen Filter. It offer a wider choice 'what amount of overdone exaggeration' you want to undo. (luminosity is my favorite choice).
Is 'focus' another feature of Photoshop. No idea, seldom use it, eagle to learn if yes.
- Thread starter
- #3
itlama,
Thanks for the reply, that was informative. The Focus feature (in our admitedly old version of PS--5.5) was a brush tool grouped with the Smudge and Blur tools. But I also use PhotoImpact and it has a Focus feature that operates on a whole selection (rather than with a brush), just like the Sharpen and Unsharp Mask. Visibly, all 3 seem to do very similar things, so I'm just confused.
My main reason is that I'm using a Nikon 7600 coopix, and I've noticed a distinct softness in all of its output compared with similar Canons and Olympus. I read that Canon simply does in-camera editing (either Sharpen,UnsharpMask, or Focus) with it's digic processor. So I'm just trying to get the same sharp output, but I don't want to over-process.
--Jim
Thanks for the reply, that was informative. The Focus feature (in our admitedly old version of PS--5.5) was a brush tool grouped with the Smudge and Blur tools. But I also use PhotoImpact and it has a Focus feature that operates on a whole selection (rather than with a brush), just like the Sharpen and Unsharp Mask. Visibly, all 3 seem to do very similar things, so I'm just confused.
My main reason is that I'm using a Nikon 7600 coopix, and I've noticed a distinct softness in all of its output compared with similar Canons and Olympus. I read that Canon simply does in-camera editing (either Sharpen,UnsharpMask, or Focus) with it's digic processor. So I'm just trying to get the same sharp output, but I don't want to over-process.
--Jim
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