It is for some time since I have been doing various experiments with blurs and its role in artistic expressions. I have tried to analyze quality of different blurs – blur due to controlled de-focus, blurs caused by software filters like gaussian blur, blurs which are results of applying a vaseline on lens/filters, blurs due to narrow extension tubes on very wide angle lenses like 20mm etc. Interestingly all have different (artistic) qualities ! May be I will defer the comparative analysis to another blog post in future. Let me share some of my understanding of blur in this blog.
Appreciation of image in my understanding has two parts – first, deciphering (seeing) the pixels and then connecting them with our experience in life.Our eyes and brain are very active in the first part to decipher the image and its beauty while during the second part mind (another part in the human brain probably) tries to relate the image to our past learning and experiences in life. Personally I believe only a few images have this latter characteristic of being able to connect with the rich experience of life. I also believe an image will be remembered for long if it stimulates thoughts beyond the image itself – that is what happens in the second phase.
Now, what is that discussion to do with blur and sharp ? It has a role. Eyes spend lots of time deciphering sharp details in an image for long. If it gets stuck for long the second phase may never take place hence affecting the overall impact of the image itself. For example look at the dew drops image below (you may click on these images to see them larger). The eyes will have tendency to go on and on looking at those dew drops. Finally the visual process ends there. It fails to stimulate anything beyond that. The effective hand off from the image to open thoughts does not happen in this case.
Compare that to the image at the top. Thanks to no detail the first phase of deciphering the image ends quickly. The lack of details makes my mind wonder about the bird in space, about the black out of focus grass region, about the empty white space etc. While thinking all these the mind is loosely connected with eyes while other thoughts freely run in the mind. In a related note just a blurred image won’t help. The image should have a carefully designed content to stimulate open thoughts.
On a lighter note a friend of mine was wondering why would I buy a super sharp 70-200mm f2.8 lens (costing $$$$) with best MTF chart if I wanted to apply vaseline on the filter 
