Sharpening

[deadman]

Seperate to my getting a new LCD monitor I now notice that a lot of my images and indeed others photos can look somewhat over sharpened. Or rather I see artefacts where I previously did not on my CRT (Which pales in comparison to the LCD I might add).

Monitors can be decieving. I am definitely reduce the sharpen on my camera and not go so heavy on unsharp tool in my paint prog.

How many others here use sharpening a lot?

[Pave]

Well, if you mean sharpening the pictures in their original size, I don't do it too often but if I need some crop (of a small bird for instance) I use it (on that crop) VERY often.
But I'm just an amateur and there are many others who have more experience.:)

[erichlund]

Seperate to my getting a new LCD monitor I now notice that a lot of my images and indeed others photos can look somewhat over sharpened. Or rather I see artefacts where I previously did not on my CRT (Which pales in comparison to the LCD I might add).

Monitors can be decieving. I am definitely reduce the sharpen on my camera and not go so heavy on unsharp tool in my paint prog.

How many others here use sharpening a lot?
The first question is do you shoot raw or jpg. I'm not familiar with the S2, but IIRC, it does have a raw capability. I always shoot raw, and the photos with no sharpening applied are soft out of my D200. This is as expected. In post processing, do all the steps you are going to do, such as color and dynamic range adjustments. Your final steps are cropping and then sharpening, IN THAT ORDER. You can crop early to get rid of really gross stuff, but final cropping should be reserved for the final, processed image. Sharpening should only be done to the final, processed image.

I won't begin to tell you the fine points of sharpening, because I'm only a beginner at it. Experts in this area use two and sometimes even three stages of sharpening, whereas I currently only use one.

Use USM (Unsharp Mask) in preference to in camera sharpening. The camera uses USM as well, but since it likely has 3 or 5 stages of sharpening, it cannot be very subtle. You have much more control when you use USM.

USM has three components, which have different names depending on the brand of tool you use, but the names are usually synonyms of these: amount, radius and threshold. USM enhances edges, which is what sharpening is all about.

Amount is the strength applied to the meeting point of two edges, and defines the contrast of the edge. In Photoshop, 80-120 is fairly typical, whereas in Nikon Capture, I use 50 to 70, so it varies by tool. I've seen people use values up to 500 with Photoshop, when combined with a very small radius.

Radius determines the width of the edge. Its use will vary depending on the intended target of the image. For instance, if you want a screen image as 75 pixels per inch and a print image at 300 pixels per inch, you would use a much smaller radius with the second, high resolution image. Typical radius for Photoshop range from .5 to 2, while I use larger values, from 2 to 5 in Capture. Amount has a very symbiotic relationship with radius. If radius gets too large, a high amount will cause halos to appear along edges. This is undesireable.

Threshold is the space between edges. A low number indicates that very little space is needed before a new edge can be defined. A high number forces more space between edges. If the number is too low, smooth areas can become speckled because individual pixels become edges. A high number can leave the image relatively unsharpened. Typical values are 0-5. Higher values (up to 255) have very little additional effect. Generally, use 0 or 1 for very detailed objects, 3-5 for faces, and 2-4 for typical work.

Some USM tools, like that of Nikon Capture, also let you sharpen in individual color bands (Reg, Green and Blue). This just adds further control, and I have not yet played with this.

USM cannot be undone once saved. Your original raw photo is your unprocessed film. Do all your other steps except final cropping and then save your work. This becomes your negative. Keep these first two forever. The next step is to crop and then use USM on your negative, based on your intended usage, and save this as the final, FOR THAT PURPOSE. For another purpose, go back to the negative, crop, sharpen and save again.