Developed in the ’50s as Superscope, or Superscope 235, the Super 35 format uses the full width of the standard 35mm film frame, not leaving room for an optical audio track. This gives about 33% more image area, and increases the aspect ratio from 1.375:1 to 1.85:1. That’s like going from 4:3 to 16:9 in television terms.
Super 35 didn’t become popular until the late ’80s, but has since become the standard for most features shot on film and digital. It provided a more cost-effective way to get a widescreen look, and with far less complications than anamorphic.
DIGITAL ANAMORPHIC REVIVAL
Super 35mm had anamorphic beat for a long time; it was more cost-effective and didn’t require theaters to have a de-squeezing lens for projection. But anamorphic is coming back in a big way, thanks to digital. With the use of digital intermediates and digital cameras, movies now can be captured with anamorphic lenses, but displayed in the theaters using standard projection. The digital process easily allows the anamorphic originals to be properly stretched out in post and either printed back to film or projected digitally—no special lenses required. This has allowed more and more filmmakers to go back to anamorphic lenses.
The widescreen aspect ratio of CinemaScope was 2.39:1, which is what most features shot on anamorphic will be shown in today. You could easily crop Super 35 film or digital sensors to get to that 2.39:1 aspect ratio. Just cut off the top and bottom; it’s wasteful, but it works.
However, the aspect ratio isn’t why most cinematographers opt for anamorphic today; instead, it’s the "look" of the lenses. Many of us just love the way anamorphic lenses look, their imperfections and aberrations included. The streaky lens flares and stretched out-of-focus areas of the image all can be appealing. It’s fair enough in this digital world of pixel perfection that many DPs desire the look of these lenses.
THE CROP FACTOR
Now, getting back to the question at hand, let’s talk about what these lenses look like on our modern digital sensors. Interestingly, we often talk about sensor resolution today in terms of horizontal resolution; 4K sensors have 4096 pixels across. In anamorphic, however, it’s the vertical dimension of the sensor that matters. Remember that anamorphic was originally designed for a format around 22mm wide, much thinner than current Super 35-sized sensors.