Cinema projection aspect ratios are quite different than the video aspect ratio.
This means that the video image area must be cropped on the top and bottom to fill
the projection screen. The entire video image can be shown in the projection area with
no cropping by adding black to the sides of the image, which is called "letter boxing".
If the letter box technique is not utilized, cropping of the video frame will occur.
Using the D-1 standard of 720 x 486, Standard Academy Camera
Aperture will utilize 720 x 350 and Anamorphic Camera Aperture
(a.k.a. Cinemascope, Panavision, and
Widescreen) will only use 720 x 274. To avoid losing vital information, all
logos and graphics must be kept in these areas. Normally, the image
can be repositioned to favor the top or bottom of the image when cropping.
The following table shows various resolutions at the common aspect ratios.
Though any resolution and pixel aspect can be used in digital effects, best results are
obtained when proper attention is paid to maintaining correct aspect ratios for the
desired film output.
|Full Camera Aperture
||1024 x 768
||2048 x 1536
||4096 x 3072
|Academy Full Frame
||914 x 666
||1828 x 1332
||3656 x 2664
||914 x 550
||1828 x 1102
||3656 x 2202
||914 x 494
||1828 x 988
||3656 x 1976
||914 x 774
||1828 x 1550
||3656 x 3098
|UN squeezed image
||914 x 388
||1828 x 778
By protecting for these respective areas, you can use the Full Camera Aperture file sizes in both Full and Academy aperture. Please note: It would be advisable to protect for the variation in projection aperture plates.
Normally the aspect ratio is 1.85 but you should always protect for 1.66 for international projection practices.
Image aspect ratios can be a confusing issue when going to cinema release, so consult with transfer facility ahead of time with questions to be certain of the process.