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Focusing software?


conniemayw 15 100 United Kingdom
19 Sep 2005 9:24AM
I recently used the trial version of FOCALPOINT and found it quite useful for those images that are just off focus-however it takes eons to perform its functions! (running it on an old pc though)
any recommendations for similar or observations would be very welcome
thanks in anticipation
connie

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CamelTrophy 14 26
20 Sep 2005 6:18AM
Heres my pennysworth....

Image files produced by scanners and digital cameras tend to
be softened due to the actions of electronic filters which are
used to remove rogue pixels - an effect known as aliasing.
This means the detail in image files can be improved by
resharpening them.
The most common method for performing sharpening is
Unsharp Masking (USM). Although this sounds like a misnomer
for an image sharpening process, it is actually based on an
old printing technique which was used to enhance image
edge details. When an image is in Lab mode, we recommend
sharpening is performed on the L (Lightness) channel:
Filter > Sharpen > Unsharp Mask
When in RGB or CMYK use Unsharp Masking (USM) with
particular care: image sharpening is definitely better underdone
than overdone. In RGB or CMYK gamuts USM sharpening
adjusts the colour of the image - so if over saturation is
noticeable it may be best to convert the image to Lab mode
or try the High pass technique that follows.
With a layered image, flatten the file before applying unsharp
masking to ensure the sharpening is applied equally. As this
implies it is also possible to apply sharpening to layers, or to
selected parts of an image.
One alternative is to use the Photoshop Sharpen filters, but
these do not offer the fine controls of Unsharp Masking:
Filter > Sharpen / Filter > Sharpen More

I suggest the Amount is dropped to 150 and increased
to 200 to make a bracketed comparison for fine tuning. A
setting of somewhere between 130-200 should be suitable
for most high resolution images for printed output.
Once you are comfortable with the effect, try small adjustments
to the Radius and Threshold as required. It is worth noting
the settings you use, especially if you have a single source,
a single output device and a preferred output size. It is also
common, for example, for social photographers to keep images
of people slightly softer than commercial images, as sharp
detail can be unflattering.

The higher the radius figure the more pixels are affected. USM
should only be used to sharpen the edge pixels so this figure
should generally be no more than 1-2 in the majority of cases
(this setting is in fact resolution and image dependent).
The threshold is used to determine which pixels are counted as
edge pixels. This measures the difference between pixels on
a scale of 0-255 (this number being the scale that produces
continuous tones in each colour channel). A figure of 5 will
alter all the pixels which differ by 5 shades or more.

One of the chief problems of image sharpening relates
the fact that output devices all tend to perform differently
and some printers apply automatic sharpening. This means
sharpening could be performed again when you send your
image to print.
For this reason it is best not to sharpen generically prepared
images. Instead we suggest you leave sharpening until the
last possible stage (after the image has been scaled and
converted for output).
USM can also produce colour shifts and halo effects at the
edges and heavy-handed use probably causes more damage
to digital images than any other imaging tool. So above
sharpening is better under done than overdone - you can
always add a little more sharpening later if needed but you
can never undo it again afterwards.

My preffered method of sharpening is to use the High Pass
filter. First duplicate the image layer:
Layer > Duplicate Layer
This will automatically select the top layer; now apply the
filter to the top layer:
Filter > Other > High Pass

Adjust the settings so the colour of the image does not appear
this means the colour of the image will also be affected)
and so the edges of the image are just visible.

Using the Layers Palette Blending Mode options (default is
Normal) select Soft Light. Click the eye symbol beside the
Duplicate Layer on and off to see the effect of the filter on the
image. If the effect is too soft select Hard Light instead.

The image can be saved in layers as a Photoshop file or Tiff
so you can adjust the effect later, or simply throw the top
layer away. However, if you are ready to print simply flatten
the image:
Layer > Flatten Image
Or use the Layers Palette Sub Menu to Flatten Image.




Hope it helps though

CT
conniemayw 15 100 United Kingdom
20 Sep 2005 9:31AM
thanks - i think that was worth more than a penny!! I do use usm at settings of amount 20 radius 50 and threshold 0. Then I fiddle about and if I need to then I use High Pass sharpening (soft light blend and usually only 1 to 3 pixels worth)However I just thought that another programme could maybe offer something better!!
thanks for your reply
regards
connie

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