Thanks
I have printed out the two tutorials part 1 and part 2
And now this thread also... lots to digest here for me.....but I am getting it
I think I have a tendency to over sharpen I think
If I don't see a difference at normal view then I want to increase everything.
I think I need to remember to keep it at 100 or 200% magnification
And not pay to much attention to normal view
But this seems to help:
There are no universal right USM values that will work for every image. But there is a fairly simple 3 step procedure for finding good values for each particular image. Start by turning up all the values to very high levels: Amount: 500; Radius: 5; Threashold: 0. Zoom in on an area of interest to about 100%. Make sure you are in LAB and have the L channel selected, but all channels visible. Then:
Tune the Threshold value by increasing until the noise in areas with no detail goes away. Usually for this will be a number between 15 and 30, but your mileage will vary dependend on ISO, raw conversion, light conditions, and subject matter. The threshold controls the when sharpening kicks in. Larger values here mean that sharpening happens only for more procounced transitions. So a low threshold value implies more sharpening. Set this value to 0 and you'll end up with a lot of sharpening where you don't want it, essentially sharpening noise and makeing it visible. Set it to 100 and you'll end up with no essentially no sharpening at all. I usually end up somewhere between 15 and 30.
Tune the Radius value by decreasing it until the halos no longer overlap and obscure detail. The Radius value controls how wide the halos are. With Amount set to 500, the halos will be quite visible which makes this easier. You may need to look at more than one part of your shot to get this right. I find I often end up with numbers between .7 and 3. The right value is a dependent on both the resolution and subject matter of the image. The subject matter is important because halos will overlap when two transitons are close to each other. In the "Believe" shot, the grain on the tombstone has lots of very fine transitions: the speckles in the granite and so the radius I chose to make nice visible halos in the print really doesn't work for the granite. The halos overlap and make a mess.
Tune the Amount value by decreasing it until halos are not actually visible, but the image still looks sharper than the original. Amount controls the opacity of the halos. At 500 they are close to completely opaque and at 0 they are invisible. Use the preview check box to switch back and forth between the sharpened version and the original. At this point you are trying to make the magic trick actually work. The illusion should be effective without the trap door being visible. I often find that values betwee 200 and 400 work here. Again, this is very dependent on the image being sharpened. It has a lot to do with the contrast between the light and dark areas in the transition, how light or dark the image is. If you use too small a number here, the sharpening will make no noticeable improvement and you might as well not have done it. Too large an amount and your viewers will see the sharpening and not your image.
Usually it's the light halos that are visible and force smaller amounts. I'm going to cover a technique that allows for greater amount for the dark and halos in Part 2.
Comments
I have printed out the two tutorials part 1 and part 2
And now this thread also... lots to digest here for me.....but I am getting it
I think I have a tendency to over sharpen I think
If I don't see a difference at normal view then I want to increase everything.
I think I need to remember to keep it at 100 or 200% magnification
And not pay to much attention to normal view
But this seems to help:
There are no universal right USM values that will work for every image. But there is a fairly simple 3 step procedure for finding good values for each particular image. Start by turning up all the values to very high levels: Amount: 500; Radius: 5; Threashold: 0. Zoom in on an area of interest to about 100%. Make sure you are in LAB and have the L channel selected, but all channels visible. Then:
- Tune the Threshold value by increasing until the noise in areas with no detail goes away. Usually for this will be a number between 15 and 30, but your mileage will vary dependend on ISO, raw conversion, light conditions, and subject matter. The threshold controls the when sharpening kicks in. Larger values here mean that sharpening happens only for more procounced transitions. So a low threshold value implies more sharpening. Set this value to 0 and you'll end up with a lot of sharpening where you don't want it, essentially sharpening noise and makeing it visible. Set it to 100 and you'll end up with no essentially no sharpening at all. I usually end up somewhere between 15 and 30.
- Tune the Radius value by decreasing it until the halos no longer overlap and obscure detail. The Radius value controls how wide the halos are. With Amount set to 500, the halos will be quite visible which makes this easier. You may need to look at more than one part of your shot to get this right. I find I often end up with numbers between .7 and 3. The right value is a dependent on both the resolution and subject matter of the image. The subject matter is important because halos will overlap when two transitons are close to each other. In the "Believe" shot, the grain on the tombstone has lots of very fine transitions: the speckles in the granite and so the radius I chose to make nice visible halos in the print really doesn't work for the granite. The halos overlap and make a mess.
- Tune the Amount value by decreasing it until halos are not actually visible, but the image still looks sharper than the original. Amount controls the opacity of the halos. At 500 they are close to completely opaque and at 0 they are invisible. Use the preview check box to switch back and forth between the sharpened version and the original. At this point you are trying to make the magic trick actually work. The illusion should be effective without the trap door being visible. I often find that values betwee 200 and 400 work here. Again, this is very dependent on the image being sharpened. It has a lot to do with the contrast between the light and dark areas in the transition, how light or dark the image is. If you use too small a number here, the sharpening will make no noticeable improvement and you might as well not have done it. Too large an amount and your viewers will see the sharpening and not your image.
Thanks for all the help guy & galsUsually it's the light halos that are visible and force smaller amounts. I'm going to cover a technique that allows for greater amount for the dark and halos in Part 2.
Fred
http://www.facebook.com/Riverbendphotos