Slow Aperture Shapes vs. Fast Aperture Shapes

 

The Sagelight Lens Blur/Bokeh function has a number of 'Aperture' Shapes, some of which are outlined below:

 

 

These shapes determine not only the how the will look but also how the blur is performed internally.  The more complex a shape the longer the blur takes because the shape is less predictable.

 

Shapes that have more solid areas blur much faster than those that have more gradient/fuzzy areas.  When you are using the display, it can be much faster to use a faster shape while using the controls and then using a more complex shape afterwards.

 

Pressing the Accept Button

 

Most images display at a smaller size than their actual size in memory.  Sagelight Bokeh routines are written for a very fast display, performing partial updates and blurring only where necessary.  However, the output file is much more detailed and can take longer.   If an image displays at 1600x1200 in memory but is actually 3200x2400, the same blur will take 4 times as long.  But, since it has higher quality than the display (i.e. preview image), this means that the result blur can take upwards of 10-15 times longer.

 

When using slower shapes keep in mind that the result image may take much longer to render than the display image.  With high radius values, a high-quality blur can take much longer to complete than the display/preview image.

 

FFT Blurs

 

If you're familiar with FFT, the question may arise about why the end-result can take a while, especially compared against some other programs.  The reason is this:

 

Some programs use an FFT blur to perform the blur on the largest size radius which can cover a large portion of the image.  However, FFT blurs leave artifacts and can also leave a circular imprint -- when mixed with non-FFT blurs -- on your image that can show up later. 

 

Sagelight takes a more conservative approach to keep the quality high in your image and does not use FFT blurring for the Lens Blur/Bokeh routines.  This does cause the end-result to take longer, but the results have more quality to them.

 

 

Tips to Keep the Display Fast

 

1. Use a solid, 'fast' shape while using the controls.  This will keep the display much faster, and then you can use the more complex shapes later.

2. The smaller the window, the faster the display.  You can select a dual-mode display that will display the original & current image.  This will shrink the image.  You can also use the Image View Navigator to shrink the window size.