Refocusing

With out-of-focus blur, an image is blurred the same amount in all directions.  It is important to correctly differentiate this from motion blur where the blur is only in one direction.  For more help with this, see the Tutorials.

Example

Photo of an ear, out of focus
Before
Photo of an ear, refocused
After

This “Before” image of a girl’s ear was re-focused using a Blur Width of “20” to produce the “After” image.

Refocusing Procedure

There are 6 steps to re-focus an image:-

Step 1 - Start with the Best Image Possible

The more pixels you give Focus Magic to work with, and the more accurately the color of each pixel is defined, the better the result will be.  Wipe any dust off the photo before scanning it in.  Scan it in with a high resolution (dpi) and edit out any bits of dirt.  If you are saving it as a JPG, then save the JPG file with the highest quality setting (i.e. the lowest compression possible).

Step 2 - Set the "Image Source"

The “Image Source” optimizes the focusing algorithm for that particular source.  The focusing algorithm is more conservative for sources which are less accurate (eg. TV – Poor Quality), and is more aggressive for sources which are more accurate (eg. Digital Camera).  Non-linearities are also taken into account for photographic film and CCD’s.  The difference to the output is quite small, but worth it if you know what the image source is.

Step 3 - Determine the Best "Blur Width"

In order to focus an image, Focus Magic needs to know the amount by which the image is out of focus.  This is specified by the “Blur Width” which is the distance that an edge has spread (in pixels).  When you open an image, Focus Magic auto-detects the Blur Width, but it is advisable to experiment a little.  Simply click on an area that you want to focus.  Focus Magic will focus that small area using the current filter settings.  Adjust the “Blur Width” up or down until you get the best result.  Changing the “Blur Width”, automatically updates the preview image.  Repeat the process for a few different parts of the image.

Examples of Different Blur Widths

Blur widths of an edge in an image

In some images, you can determine the “Blur Width” more accurately from a point source.

Step 4 - Select the "Amount"

Once you have determined the most suitable “Blur Width”, select the most appropriate “Focus Amount”.  This is normally set to 100%, but you can tell Focus Magic to under compensate or over compensate with amounts which are less that 100% or greater than 100% respectively.

Examples of different focusing amounts:-

Original blurry image
Original
50% amount example
50%
100% amount example
100% (Default)
200% amount example
200%
300% amount example
300%

Step 5 - Select Noise Reduction

This can normally be left to Auto.  For a full explanation, see Remove Noise.

Step 6 - Focus the Whole Image

Once you have done some spot checks on the image you can press the “OK” button to focus the whole image.  There is a huge amount of number crunching to do, which can take from a few minutes to over an hour for a very large image.

If you want to abort the image processing, simply press the Esc key.

"Focus Magic is a remarkable piece of software. It's an honest-to-God real sharpening algorithm that works as a stand-alone program or a Photoshop plug-in. I'll spare you the math about how it works. What's important is that this is not a mere edge-enhancement routine like most so-called sharpening filters; this one actually undoes the blur."
Ctein (Photographer & Author)
Ctein
Photographer, artist, author