Understanding Aspect Ratio

Sometimes You Have to Give A Crop!

I have written about this before (and I wrote about it again), but I still keep hearing photographers and clients having trouble understanding aspect ratio and how this applies to photographic prints.

Different format cameras take images in different aspect ratios. The aspect ratio of the camera is the size relationship between the long and short sides of the image. The most common aspect ratio for digital Single Lens Reflex (dSLR) camera is 2x3, which is based on the old 35mm film format where the size of the negative was 24x36mm. 24x36 simplifies down to 2x3 or 2:3. Print sizes in this aspect ratio are 4x6, 8x12, 10x15, 12x18, 16x24, 20x30, and so on.

However, many of us are used to print sizes that are aspect ratios like 5x7, 8x10, and 11x14. These three ratios are all different and do not simplify down to the same number. That means that if you start with a 2:3 image and want to print at 5x7, 8x10, or 11x14 the image is going to have to be cropped from the original, cutting off part of the image. Or the image can be printed at its full 2:3 ratio, but with uneven borders (the borders on the long side of the print will be wider than those on the short side).

Here are some illustrations. The first one shows 4 crops of the same image. The first one is the full 2:3. The second shows the 8:10 crop. The third is the 5:7 crop. The fourth is the 11:14 crop. You can see how parts of the image get cut off in these crops.

This next image shows crop overlays in various colors. The overall black border shows the full 2:3 image. The red lines show the 8x10 crop. The green lines show the 5x7 crop. The yellow lines show the 11x14 crop.

The final image shows the effect of putting the full 2:3 image on other ratio papers. The paper shapes are shown by the blue outline and the extra white space/margins are shown in purple.

As photographers making images for our customers we need to be aware of the different print sizes and shapes. Many of us have been taught to always fill the frame, but that isn't always effective. It is nice for our "art prints" where we will control the printing and only offer specific sizes or custom matting. But in many situations we need to leave some extra "breathing room" around the subject to allow for cropping to different print aspect ratios for client prints, standard frame and mat sizes, and albums. If you offer an 8x10 album but all of your images fill the 8x12 frame you are going to have tough decisions to make in preparing the images for the album. Keeping the 8x10 ratio in mind while making the images in camera will save you.