why is this?

what really is 'unsharp mask'?

Sharpening is done a pixel level and you can only see the pixels at 100%--the monitor is just interpolating the image at a smaller percentage and you really cannot see what is happening.

A unsharp mask is a originally a film technique were a separate film mask was generated from the original negative and sandwiched with it for printing. The mask was made using a diffusion material and so it was not sharp.

Basically, the unsharp mask emphasizes edge contrast by using a soft negative image. This has the effect of increasing the the contrast of edges by building up the light side and lower the dark one. When too much masking is applied, you get halos--the contrast is simply too much.

The amount is simply how much contrast. The radius is describing the amount of blurring of the mask. You can think of the radius as a frequency slider, the higher the frequency detail (how fine it is), the lower the number, the finer the detail you are affecting. This setting is also very dependent on the number of pixels in an image. If you are working in RAW, 1 is a great place to leave it--this becomes a really complex topic which a forum post cannot really answer. The threshold is limiting the definition of an edge--the threshold is given in levels and so if you specify a level os 6, then if the luminance difference between pixels is 6 or less, then those are ignore and not considered an edge.

That is really the simple definition of an unsharp mask.

On Olympus cameras sharpening set at zero is what the camera deems to be "standard sharpening," not as you might expect "no sharpening." I set mine to minus 2 (which is as close as you can get to no sharpening) on the basis that I would rather decide how much sharpening to apply in pp according to how I'm going to use the image. You can always sharpen more but once applied you cannot take it away.

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OK here is an example of one that I think printed quite badly. Looking at it at 100% is scary!





Now with the 60D set to higher levels of USM it would have printed fine up to 16x20 (again sorry I don't have the camera any more so I can't really compare. But I have many photos set to the normal levels I'd use and those prints are great.) I can't remember what settings I had the camera set to, probably normal to low sharpening.

I've never been good with photoshop so I'm not sure what to do to make it better, which is why I'm asking here.

You shoot JPGs right? I would make sure your file/compression is set to Large/Fine and take a series of control shots with in-camera sharpening set to each option. One will be on target for what you want.

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Yeah I shoot jpeg. It's set to Large super fine. When I have some time in the next day or two I'll try to see if changing the sharpening down helps. Problem is it looks fine in some shots. Like my close-ups and macro it looks great and I've even had to use USM twice on a couple images. It's a bit like my old G11 was. So I'm assuming it's the in camera sharpening I'm not liking.

I'm no photo editing guru master, but I downloaded the crop you posted, and increased the contrast some and added some sharpening using paint.net(I'm afraid it's all I have where I'm at.) Do you think this looks any improved compared to the original crop you uploaded?

Your image is soft--the 100% is showing you. There are two things that are really going to help, contrast and sharpening. You should always change contrast before sharpening.

Contrast:

Here you want to use curves. Curves is simple. The box shows black at the left bottom and white at the top right. The diagonal line is the image. If the line is moved above the original position, the image gets lighter. If the angle of the line is greater than 45 degrees, the contrast increase.

I looked at your image. Open it up.

Go to a point at 2/3 to 3/4 to the top of the line and move it slightly up--you should see the highlights and mid-tones lighten. You should see an increase in contrast as well. The reason I started to the top is that most of the tones in the image are toward the bottom--the histogram seems to indicate slight underexposure. By moving the top of the curve up, I am moving the lighter tones to where they should be and the mid-tone and shadows should follow nicely.

Now, if the shadows and dark areas seem a little too bright, and they did for me, click on the lower section of the line and bring it down to meet the original line position--you should see a deepening of the dark tones. I found going below the original line position made the contrast too harsh and your blacks blocked up--this is not surprising as the image seems underexposed. With this image, you may not want to hard a black--the black T-Shirt blocks up fast making it look like a black hole. You can keep moving these two points to refine the curve.

When you get the contrast right, it is time for unsharp masking.

Unsharp mask.

This should be done at 100%

I found that a percentage of about 40% worked well for your image at a radius of 1.0--if what you did with the curves is different from what I did, you may need to go higher or lower with the amount.

With unsharp masking, the effect is subtle. When you click the preview button on and off, it should look like someone is wiping of a thin layer of grease from your image. Thing just tighten up slightly.

Now one thing we have not covered is what is happening to the image through the printer. If what you are doing here not the problem, we can talk about how this image you posted is different from the printed image. That might be a color management (CM) issue. Usually that is manifested as an unexpectedly large shift in contrast and color saturation usually cause by a profile mismatch.

I have never really used curves. I tend to use levels. I'll try your suggestion of using that. With the OMD in levels in a lot of my images I'm having to brighten them up a bit then they look more like what I see. I probably should take a class in photoshop. The last one I took was for 2.0! ha ha!!

With USM I keep the little window at 100% but tend to look at the larger preview. I didn't know you're supposed to use it at 100%, to my eye it's harder to do that, it's harder to imagine the rest of the image.

Can anyone recommend PS books that might help me with sharpening and other things. I can do a few things, but when it comes to printing large I'm not sure how to edit. I used to only print to 8x10, now that I prefer a much larger size I'm realizing my editing is off with the OMD. I just got prints (2 weeks late and VERY damaged no thanks to the USPS) one is the 60D scene of a waterfall 16x20 (143706829 photo - gardengirl13 photos at pbase.com). Looks great. They darkened it more then I like but the leaves all look normal. The print from the OMD which is only 4x6 (the photo above) and I can see smudging and what looks like over-sharpening. Now I have another 16x20 print from the OMD (144642801 photo - gardengirl13 photos at pbase.com) which shows no signs at all of over sharpening. It looks better then some of the 60D prints of the same type of subject.

Maybe it's just landscapes (leaves/grasses) that I'm struggling with?

I use the image at 100%, rather then the preview in the USM dialog box. I take a high contrast area in the image as that is where things will go wrong the fastest and if that is right, so will the rest of the image be.

Levels is just a three point curve. The top and bottom points in curves are the black and white points in levels. The gamma slider is like putting a single point in the center of the curve and moving it up or down.

Low contrast scenes like your forest are tricky as the trees are more contrasty and so by the time you get the leaves great, then the trees are too much. What you can do in that case is simply apply sharpening to a specific color channel instead of the master channel.

I would simply go to Amazon and have a look at the offering and see how folks rate it. I have not used a how-to book in years--I do actually train folks in Photoshop. You should also find resources online for this as well.