Prezi lets us pan, zoom and roll the virtual camera. The latter is rarely seen, for good reason. A rolling rotation is not natural for us human beings. When we are not currently practising handstands, there is a good chance that we almost never roll our heads at heavy angles. Slight head tilts on the other hand, for example during a conversation or while posing for a photo, are perfectly normal.
How to roll?
In Prezi, we can roll the camera by rotating either the graphic, zoom area or the whole topic. You do that by first selecting it and then moving your cursor to the corners of the selection frame. When you now hit ALT + CTRL/CMD (Windows/Mac) the cursor should change. A left mouse button click and moving the mouse up or down will rotate the element. You can snap to certain angles by holding down the shift key on your keyboard.
Interestingly, Prezi limits the camera rotation to an angle of 180°. This is because Prezi decides whether it does a roll left or a roll right based on the shortest angle. So if we rotate a zoom area 90° to the left, Prezi rolls the camera left and does not roll the camera right for 270°. When we rotate our object 181° to the left, it now will roll the camera 179° to the right because this angle is smaller. That means, if you would like to make a 360° full camera roll, you have to split it up into two clicks.
With all this unnaturalness and discomfort of rolling a camera, are there any occasions when our presentations can benefit from it?
Rolling a camera is uncommon, even in movies, more so in presentations. We can use this to our advantage. When we use a camera roll, it comes as a surprise. No one expects that a scene would rotate. It, therefore, can be a great transition effect, keeping the audience engaged and entertained.
In presentation tools like Prezi that make great use of the match cut transition, we sometimes need our composition to harmonize with additional text elements. Using a camera roll allows us to have absolute control over the final composition.
As you can see, rolling the virtual camera can contribute to the overall experience. When you are planning to use a camera roll inside your presentation, you should consider the following:
The farther the distance between the audience and the presentation screen is, the less nausea camera rolls will create. Big events usually come with big screens. Do the first few rows a favour and keep this side effect in mind while designing the presentation.
A virtual camera roll is an uncommon motion. We do not see it so often because it might cause nausea on big screens. But when we use it controlled, it can surprise the audience and grant us more compositional flexibility.
Keep on rolling!