Understanding Depth-of-Field

Adding defocus blur to a painting or drawing can add a great sense of depth to the work. However, adding edge softness without an understanding of what leads to depth-driven defocus blur may limit success in this regard.


(Detail from Totem, 20x16", Oil on Panel.)

Varied edge work or sharpness can produce a number of perceptual effects. It can influence where a viewer might focus attention, open a door to visual closure opportunities, as well as promote a great sense of depth. However it is the latter that I would like to focus on here.

Simply speaking, defocus blur is a common monocular depth cue. The “defocused” regions of the visual field are regions that are located outside of our eye’s depth of field. The depth of field ( DOF ) is the distance between the nearest and the farthest objects that are in “acceptably sharp focus” in an image.

Understanding the nature of “depth of field” can really help you to deploy defocus blur to promote image depth with great success. I believe that this video does a great job in communicating this:

I hope that you find this as insightful as I did!

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There’s some seriously complementary interplay with perspective and depth of field in that painting Anthony - those paintbrushes draw you right into the picture plane and man I could just touch that skull…

Great video also, I experiment with photography now and again and never quite fully understand the concepts I am messing with, so this clarifies some of the fundamentals.

Because of our eyes propensity to auto-focus and compensate for optical aberrations - we can’t actually ‘look at’ the out of focus bits in our field of vision. So I find that the blurred out of focus areas captured in a photo or designed in a painting quickly capture my interest.

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I’ve always been curious as to how you achieve your DOF within your artwork, Anthony.
Curious as you work from observation. Do you just fabricate the DOF as to how you think it looks? Directly looking at an object brings it into focus with our vision.
For me, it’s pretty easy to emulate, as I work from photographic refs (I often Photoshop my images to exaggerate or even add in DOF, as it’s an additional element of illusion I like in my work).

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