F-200 Aspect Ratio
More and more filmmakers are "thinking outside of the box" and shooting movies in non-traditional aspect ratios. While traditionally the cinema industry works around "standard" aspect ratios of flat (1.85:1) or scope (2.39:1 or 2.35:1 for film) a increasing amount of content is arriving at cinemas in less common formats. This means that the theatre's technician or projection staff have to find a way to accommodate this content.
For the information to make sense a basic understanding of what an aspect ratio is will be required. Simply put, the aspect ratio is the relationship of the width to the height. For example, if we were to project a flat image (1.85:1) on to a screen that was 10' tall, the width would be 18.5'. Likewise, if we were to project a scope image (2.39:1) on to a 10' tall screen, the width would be 23.9'.
Now to get a bit technical. The native size of your 2K DMD chip that creates the image in your projector is 2048 x 1080 pixels (4096 x 2160 for 4K). That means that the native aspect ratio of the chip is 1.9:1 (Rounded). To get the aspect ratios that we use for cinema we actually seldom use the full chip at one time instead turning off rows (or columns) of pixels to "reshape" the chip to the aspect that we need. For example, to get flat we want to use as much of the chip as we can so we use the full height of the chip, 1080 pixels and then crop the sides, . Doing the math, this would be 1080 x 1.85 = 1998 pixels wide. We essentially turn off 50 pixels, 25 on each side. Using the same method to maximize the use of the chip, we use its entire width of 2048 pixels and crop the height. Doing this math 2048/2.39=857 (which is rounded to 858. We turn off 222 pixels, 111 each on the top and bottom.
The format referenced above, F-200, is a 2:1 aspect ratio that resides inside of a 1.85 "container". That means that the actual number of pixel used is 1998 wide (the width of a 1.85:1 "container")/2 = 999 pixels high.
To used this format the 1.85:1 aspect ratio PCF (Projector Configuration File) is used on the projector. If the screen has movable side masking, the lens can be zoomed so that the top of the picture meets the top/bottom masking. If the screen does not have movable side masking, the lens should be left alone as the width will be the same as a flat 1.85:1 picture. You will be letter boxing the top and bottom of the picture. Once the lens is set proceed to make a new screen file using the chart above.
The above chart is available as a downloadable test file at:
Related Articles
Frame Size Guide for Setting Up Aspect Ratios
Here's a quick guide for setting up PCF and screen files for various aspect ratios. Please note that pixel offsets have been rounded to the nearest full pixel and may need to be tweaked in the field. When using this to create the PCF file, it tells ...Missing Subtitles
Total Cinema Solutions Techie Cheat Sheet What Happened to My Subtitles? You’re running a foreign language film and your subtitles are nowhere to be found. There are several possible causes for this problem. Here’s a few to check out. Are you running ...NEC S2 Projector Displaying 3xx Error
NEC errors in the 300 range generally pertain to an issue with the ICP board. The ICP board contains the projector's security certificate so this can be a fatal one. There are two batteries on the ICP board. One battery can be changed, the other ...NEC Cinema equipment installations best practice guidance for extended Off times (ver1 3)
Guidance for protecting your NEC projection equipment when your theatre/post production installation might be closed for a while Due to the actual force majeure of closing cinema installations for an unknown period of time, we would like to provide ...Cinema ADA Requirements
Accessibility Technology Requirements for Cinema By Harold Hallikainen, USL (QSC, LLC) The United States Americans with Disabilities Act (ADA) was signed into law in 1990. The Act defines a “motion picture house” as a public accommodation and ...