Aspect ratio and PowerPoint using Photoshop
Often in the classroom it is of real value to develop PowerPoint presentations to display a series of pictures you have taken. For example, at the beginning of the school year you may wish to have a self-running PowerPoint displaying pictures, together with the names, of all your students. Or you may have taken a series of pictures of a class project and wish to have a PowerPoint containing the pictures running for parents to view as they wait for their individual conferences with you. Your task is then to insert each of the pictures in a PowerPoint slide and then set the timing for each picture to be shown in the automatic display mode.
In checking the specifications of various digital cameras, it appears that there are several “standard” aspect ratios, that is the relation of the width of the picture to the height of the picture. Some cameras have a 10:6.5 aspect ratio, others a 10:6.6 aspect ratio, and even others a 3:2 aspect ratio. You may very well wonder what difference that makes. Because the PowerPoint full screen slide has a 4:3 aspect ratio, you will have to crop each of your pictures if your camera has other than a 4:3 aspect ratio.
In the past I have been using an Olympus E20 which has a 4:3 aspect ratio. As long as I took pictures in the “landscape” mode, that is holding the camera horizontally, I could very quickly insert full-frame pictures into a PowerPoint presentation. However, I recently switched to a camera that has a 10:6.5 aspect ratio, and I found the task of inserting full-frame pictures into PowerPoint to be suddenly much more tedious and time-consuming.
As an example, here is the screen showing a picture from a camera displayed in Adobe Photoshop Elements 3.0. A careful noting of the horizontal and vertical rules indicates that this camera has a 10:6.5 aspect ratio.
In order to place this picture as a full-screen display in PowerPoint, I need it to be cropped so as to have a 4:3 aspect ratio, or 10 inches by7.5 inches. One approach would be to resize the picture such that it is 7.5 inches in height and then crop some off each end of the picture, and through successive approximations, eventually end up with a 10 by 7.5 inch picture. As you can imagine, even when using the ruler, that is a quite tedious procedure and the only way to really check out the result is to complete the cropping, check the dimensions, and then check the picture to determine if it were cropped appropriately.
Another approach in Photoshop, and most other picture editing programs, is to use one special aspect of the cropping tool. In this screen display, you will note that when the cropping tool is selected, the width and height of the cropped area can also be specified.
With the cropping tool and the indicated dimensions selected, the area cropped will always result in a picture with dimensions of 10 inches by 7.5 inches. When inserted into PowerPoint, the picture will be a full screen display.
What is really advantageous about this cropping method is that it is possible to move the cropping rectangle around and thus select that portion of the picture most appropriate for the PowerPoint slide. In this display you can see how the cropping rectangle has been moved.
–Norman Bell, Co-Editor