Those of us enjoying HD broadcast television have come to be comfortable with commercials and programs recorded in HD, and in the proper 16:9 HD aspect ratio. It's just the way things are done now. When was the last time you saw a 4:3 TV at a retail store? Years ago. It's rare to see a commercial nowadays in old, low technology. Anything made in the last few years has no excuse to be in proper contemporary formats. Are they still answering their rotary phones, too?
For anyone who isn't familiar with aspect ratios or video formats, here's the simple Cliff Notes version. 4:3 aspect ratio, commonly called "four-by-three" derives from 35mm film used in silent era cinema, as well as 35mm still camera film. Simply put, it's the length and the width of the screen in a ratio. We know it more as the squareish shape of the old console CRT television tubes. When television was birthed, the format was adapted from the movies at the time—a simple transition so that movies potentially viewed on TVs would all look the same as the theater. Makes plenty of sense.
This is a standard 4:3 proportion screen:
This is a typical look of a 16:9 widescreen format:
By default, unintelligent programs like Powerpoint and Keynote blindly default to a historically standard 4:3 aspect ratio, usually a 1024 pixels x 768 pixels framed canvas. These work great on your 10 year old CRT monitor but not so great on any new laptop or widescreen HD television, which are the norm now, and not the exception.
Building your new presentation into the default settings from the second you open a program already puts you into 1940s video technology. Is that where you want to be? Is that the first impression you want your audience to have of you?
So here's a tip. The first thing you should do when you are preparing your presentation slide deck is find out what the final technology will be. If it is an old school 4:3 projection screen or an iPad, keep the proportions set to the default 4:3, and let 'er rip. If you are showing on a laptop, HD TV or monitor or any contemporary projection hardware, make sure that you head into your page or canvas setup and select the 16:9 options. We prefer 1280 x 720 sizes when putting together 16:9 presentations as a good balance of file size and image quality.
If you are using 4:3 slide proportions and showing them on 16:9 screens, you are not only losing out on valuable slide space and real estate, but those black bars down the sides make you look like an amateur and unprepared. When you want to look polished and professional in every way, make sure the slides behind you are up to the task, as well.