Lense Blur
One of the most useful features introduced with Photoshop CS is the Lens Blur filter. Unfortunately Adobe failed to provide much in the way of guidance as to how it is to be used.
Sometimes you may think that how the GAUSSIAN BLUR different from LENSE BLUR?... But LENSE BLUR work entirely different way to GAUSSIAN BLUR..Notice that with the grid patterns Gaussian Blur simply softens the edges whereas the Lens Blur filter results in a blur effect that has a more geometric shape or pattern to it. Looking at the section of the image with the 4 circles (representing highlights of different sizes) we see that the shape of the blur effect in the Lens Blur example is that of a Hexagon. More interesting is that fact that with the largest circle we find that the centre of the Lens Blur example has remained white whilst Gaussian Blur has become a light grey. The actual shape of the blur effect is determined by the Iris Shape chosen by the user although not all images will show this effect to the same extent as shown above
Example:
Suppose we have an image which has a sky back ground. With the following stept we cans easly change that strong background(Sky) into an out of focus mode..
1. Select the for ground image with MAGIC WAND and POLYGON LASSO
2.Create a Mask (Alpha Channel) using the Save Channel as Mask button found at the bottom of the Channels dialog
3.Using Quick Mask mode clean up the mask so that the subject area is white and the background is black
4.Choose Lens Blur from the Filter > Blur menu
Once the Lens Blur dialog opens hold down the the Alt key and click the Reset button (Lens Blur will be set t the default values)
Choose the Alpha Channel form the Depth Map: Source drop down menu
Once the Lens Blur dialog opens hold down the the Alt key and click the Reset button (Lens Blur will be set t the default values)
Choose the Alpha Channel form the Depth Map: Source drop down menu
5.Step 5
Clicking the area that we want to remain in focus (the statue) causes the Blur Focal Distance slider to automatically move from 0 to 255 (remember 255 is white).
Next we increase the value of Iris: Radius slider and watch the background (black area) go out of focus. Adjust blur to taste!
Zooming into image so that we can view the subject and background at the same time enables us to determine the Noise Amount that needs to be added to the image so that the blurred area doesn't look unnatural.
The Radius slider located within the Iris section of the Lens Blur panel allows us to adjust the amount of blur applied to the image. In this example a value of 0 results in no blur and a value of 255 is maximum blur.
Clicking the area that we want to remain in focus (the statue) causes the Blur Focal Distance slider to automatically move from 0 to 255 (remember 255 is white).
Next we increase the value of Iris: Radius slider and watch the background (black area) go out of focus. Adjust blur to taste!
Zooming into image so that we can view the subject and background at the same time enables us to determine the Noise Amount that needs to be added to the image so that the blurred area doesn't look unnatural.
The Radius slider located within the Iris section of the Lens Blur panel allows us to adjust the amount of blur applied to the image. In this example a value of 0 results in no blur and a value of 255 is maximum blur.
