I'd like to talk with my colleagues in the visual effects and cinematographer fields about the pluses and minuses of shooting visual effects with anamorphic lenses, as opposed to spherical lenses.

From the development of Cinemascope in 1953, through the later widespread use of Panavision lenses, anamorphic has long been the preferred 35mm filming format of big feature films. But that started to change when Silverado was shot in Super 35 spherical in 1985. And then director James Cameron pushed the industry back into the common use of Super 35 spherical, with True Lies andTitanic, as well as with the Ron Howard Super 35 production of Apollo 13.

The reason that Cameron championed Super 35 spherical is that anamorphic lenses have many problematic aberrations, which make them difficult to use for visual effects, That's why the original Star Wars 4 visual effects were shot on spherical Vistavision, since anamorphic photography is quite counter productive for vfx.

So life was good for a while, in the vfx heaven of spherical 35mm photography.

But since 2010, anamorphic has been making a resurgence, especially sinceJohn Carter of Mars. And in the digital age of Alexa and Red high end production cameras, anamorphic photography has seen a rebirth.

And this resurgence is perhaps not a good thing.

This is because, from a Matchmove perspective, anamorphic sucks.

We have been working closely with 3D Equalizer for the last two years, who have developed sophisticated tools to handle the asymmetrical lens breathing of anamorphic lenses. We know that spherical lenses exhibit a slight focal length zooming during focusing, which is commonly called "lens breathing". It is easy for us to solve for animated symmetrical lens breathing in spherical. But anamorphic lenses breathe differently in the vertical and horizontal. So this asymmetrical anamorphic lens breathing is quite a headache to track, even with the excellent new anamorphic lens distortion models from 3D Equalizer. It is common for a spherical shot to be tracked in half the time as an identical anamorphic plate shot.

I recently was a Matchmove supervisor on a major Hollywood action film, which was shot with Alexa XT anamorphic, Alexa XT spherical and Alexa 65 spherical.

It is non-trivial for an visual effects professional or audience member to discern the difference between Alexa anamorphic and Alexa spherical. But anamorphic is quite painful to track, so what is the point of using that format, instead of tried and true spherical? Of course anamorphic has theoretical advantages, such as higher pixel count, weird lens flares, softer images, heavy barrel distortion and distinctive asymmetrical rack focuses.

Many current Alexa anamorphic productions are actually using Panavision C lenses, which are from the 1960s. These lenses are not very sharp, but they are much more compact than more "modern" anamorphic lenses, which are often bulky and heavy.

As a side note, the Alexa 65 footage on this same show was difficult to track, since it was almost all underexposed and quite grainy. We had many shots on the exact same sound stage set and because it was lit for T/2.8 and the larger format Alexa 65 lenses only open up to T/4. So even though the Alexa 65 is a 6K camera, an underexposed 6k image looks much worse and is more difficult to track than a plain vanilla Alexa XT spherical properly exposed.

Format	x pixels	y pixels	pixel count	aspect ratio	pixel count, cropped to 2.40:1
Alexa anamorphic 4:3	2880	2160	6,220,800	2.6666666667	5,598,720
Alexa spherical 16:9	2880	1620	4,665,600	1.7777777778	3,456,000
Alexa Open Gate spherical	3414	2198	7,503,972	1.5532302093	4,856,415
Alexa 65 Open Gate	6560	3100	20,336,000	2.1161290323	18,302,400
UHD 4k	3840	2160	8,294,400	1.7777777778	6,144,000

-Michael Karp, SOC