Wall-E Gives Good Bokeh

Leslie and I saw Wall-E last night, Pixar’s latest movie. Definitely a thumbs up. It’s a very simple movie, and as with all of Pixar’s productions has a clear message of listening to your heart, not going along with the crowd, etc. And the story pivots around man-made environmental catastrophe and supplication to mega retail dominated suburbia (and mega cruises).

Visually it is spectacular - every frame of every scene is a feast for the eyes. In previous Pixar movies they stretched the limits of a certain aspect of 3D animation - Toy Story was about texturing, The Incredibles, Monsters Inc., and Ratatouille did cloth and hair/fur,  Finding Nemo was about water. What struck me about Wall-E was the animators’ use of foreground/background, and how they managed to render atmosphere and out-of-focus areas. I don’t think I’ve ever seen an animated movie where the point of focus moves back and forth so dramatically in the frame, and where such shallow depth of field is used to emphasize key elements. It lends an incredible amount of richness to each scene, and they have the used the flexibility of virtual lenses provided by the computer animation form to push this to an extreme. Check out this frame from the trailer of Wall-E’s hands, for example:
[I’m about to embark on some photography tech trivia, so if you’re not interested skip the rest of this post]

The subtleties don’t really come across in such a small image as above (they are much more apparent on the big screen), but how the areas in the back of the frame are rendered out of focus is just brilliantly done. What also can’t be communicated by a still image is when they pull the focus back and forth in the frame and seeing how different elements in the scene respond to the shifting focus - it’s completely realistic. You probably think I’m off my nut here, so let me explain a bit more. 

Other animated movies, including ones from Pixar, have of course blurred out the backgrounds, there’s nothing unusual there. What I saw for the first time in Wall-E was the artistic use of blurring, and an amazing attention to detail of how blur occurs with real lenses. In a lot of computer animation blurring will be achieved in the same way Photoshop does it - a uniform blurring of all objects based on distance from the virtual lens. But that’s not how physical lenses actually do things. For example specular highlights (small points of light) get de-focused very differently than flat areas of color.

This is a common trick in photography, and lenses which are effective at giving a nice smooth rendering of out of focus areas are highly prized by photographers and are termed as having “good bokeh”. The term was popularized by photographer and critic Mike Johnston, who has written articles about it, evaluated lenses on it, and even written a self-published book. Some lenses, mostly primes (non zooms) do a especially good job of bokeh thanks to a particular combination of lens elements shapes and arrangement, glass coatings, and shape and number of blades used to create the aperture iris.

For example, here is a detail of shot I took of some spools of tapestry thread. Look at how the bokeh is a bit busy, with some doubling of highlights. Not bad for a zoom lens, but not great.

Here’s a photo of one our dogs, Spencer. This has extremely shallow depth of field, less than an inch, which his eyes are within so they are sharp, but everything else is out of focus. This was taken with a Pentax 77mm Limited lens which I was trying out, considered by many one of the best lenses ever made and which produces spectacularly good bokeh, as you can see here. 


Seeing it at small size sharpens it up, so here’s a 100% size crop. Creamy!:


And here’s one more from a wedding we attended recently, this time taken with a Pentax 70mm Limited “pancake” lens, which is only about an inch thick and is just a beautiful little lens, though it’s bokeh is not quite as good as the 77.


A few post-scripts:

  1. If you use a point-and-shoot (digital or film) chances are you won’t get much bokeh. Their sensors are so small that they have very large depth of field and so creating highly out-of-focus areas is almost impossible.
  2. If you haven’t seen The Diving Bell and the Butterfly, it is an utterly touching movie, visually stunning, and likewise makes fantastic use of bokeh, but in a very different much more impressionistic way.  
  3. If you haven’t seen Wanted, which we also saw this weekend, skip it. Horrible movie. Basically a 2 hour waste of time that makes the case for going postal being a socially acceptable way of dealing with the fact that your life is boring.