Converting Between Diagonal Size And Width Or Height; Converting Between 16:9 And 4:3 Image Sizes - Epson PowerLite 8300NL User Manual

Converting Between Diagonal Size and Width
or Height
The calculations on the previous pages use the diagonal length of an
image to indicate its size.
Use these formulas if you want to find out the diagonal size of a
4:3 image from its width or height:
Diagonal size = 5/4 × width
Diagonal size = 5/3 × height
Use these formulas if you want to find out the width or height of
a 4:3 image from its diagonal size:
Width = 4/5 × diagonal size
Height = 3/5 × diagonal size

Converting Between 16:9 and 4:3 Image Sizes

The image size calculations on on the previous pages assume that
you're projecting a 4:3-sized image. If you want to project a 16:9
(widescreen) image, you'll first need to determine the corresponding
size of a 4:3 image before using the calculations.
Since the projector's native aspect ratio is 4:3, the image height is
reduced when you project a 16:9 image:
16:9 image
4:3 image
If you know the height of the 16:9 image you want to project,
multiply it by 20/9 to determine the diagonal of the corresponding
4:3 image. Then use the image size calculations to determine the
projection distance.
If you've already used the projection distance to calculate the diagonal
of a 4:3 image, multiply it by 9/20 to determine the height of the
corresponding 16:9 image.
16:9 image is 75% as high as 4:3 image
Appendix A: Projector Installation
115