Iceland 2008

Cory Photography with Tom and Pat Cory

Aspect Ratios

 

We are addressing the subject of aspect ratios because it is something that we've had several questions about lately.

 

Aspect ratios are simply a way of referring to the shapes of your digital images and/or prints made from your images. It is important to understand aspect ratios if you make prints, particularly enlargements, from your digital images. This is going to get a little technical but if you are experiencing part of your images getting cropped when you make prints, it's worth the effort to understand how all this works.

 

First some background which will help explain how we arrived where we are with the common print sizes we have.  35mm film produces slides and negatives that are 1 inch by 1 ½ inches: that is, the short side is 2/3 of the long side. When this is represented by a ratio of the short side to the long side you come up with a 2:3 ratio, i.e. (2) half inches by (3) half images. A 4x6 inch print also has a 2:3 aspect ratio so a print made from a negative or slide perfectly matches a 4x6 inch print. (The short side is again 2/3 of the long size—4/6 is the same shape as 2/3.) When digital photography came about, it made sense to choose the most commonly used aspect ratio as the standard for digital images as well so in most cases your digital images also match 4x6 inch prints exactly.

 

In the film world, there are also cameras that use film sizes other than 35mm film: 4x5 inches, 5x7 inches, and 8x10 inches among others. Just as in the digital world where more pixels typically mean the ability to produce larger prints with better detail, these larger negatives can also produce more detail in enlarged prints than the smaller 35mm film due to the large negatives. So the purpose of using these cameras with the larger negatives is generally to create large prints. Thus the introduction of 5x7, 8x10, and 16x20 inch prints to match the aspect ratios of these cameras.

 

So our problem arises when we make a 5x7, 8x10, or (any other non 2:3 aspect ratio) inch print from our digital images since none of these standard size enlargements are the same shape as our digital images. When you print any of these standard size prints directly from your digital images something is going to have to be cropped off to fit the print size. Take for example the 8x10 inch print. If the short side is 8 inches, to make a print with a 2:3 ratio you would have to make an 8x12 inch print. (Divide both 8 and 12 by 4 and you get 2:3.) In the 8x10 inch print, two full inches will be cropped from the long side of the image! Therefore, if you are going to make a print that is not of the same aspect ratio as your digital file and you want to control what part of your image is cropped, you will need to crop your image into the aspect ratio that will give you the correct shaped digital file to make your desired print. And it gets worse—if you want to be able to print 4x6, 5x7 and also 8x10 inch prints from the same digital image you will need to have 3 different versions of your image with the correct aspect ratios if you want to control the part of your image that will be printed. If you want to sell your prints in different sizes, you must take this into consideration when previewing your images to the buyer to avoid any surprises.

 

Because of this situation with enlargements, if you plan to make a lot of prints that are larger than 4x6 inches, when you take your photo you may want to allow a little extra room around your subject to give yourself some room to crop without removing the important part of your image.

 

Now, there is one more little detail that confuses things even more.  Some digital cameras don't create a 2:3 ratio image but rather an image with a 3:4 ratio and some even allow you to choose either shape. This is because a standard computer screen and a standard TV screen have a 3:4 ratio and the assumption is that you may want your image, when displayed on your computer or TV, to fill the screen.  So if your camera is making images that are a 3:4 ratio you will have part of your image cropped if you make a 4x6 inch print. And to complicate matter even more, enter wide screen TV's, computer screens and panoramic images with even more shapes. All of this can be very confusing.

 

If you find this article confusing, just remember two things.  (1) If you are experiencing part of your image being cropped off when making 4x6 inch prints, check your camera image size setting to see if it is set for something other than a 2:3 aspect ratio.  (2) If you make standard enlargements from your images, something will get cropped off and it's not the fault of the printer, it's just the way things work. If you use image editing software on your computer or do your work at a kiosk, you can control the way your image is cropped.  If you just send off your file for someone to print for you and your desired print is a different shape from your digital image then you run the risk of having an important part of your image cropped off in the print.