What is Aspect ratio?

and why does my photo have to be cropped to print sometimes?

I previously wrote an article about Cropping in Lightroom, and while that was specific to how the tool works inside Lightroom, cropping is a part of every single image viewer and tool I think I’ve ever used.

A lot of the time people do it free-form and just crop to what looks best, but it’s very important I believe to keep in mind your intended output, that is where this final image is going to be displayed.

If you are printing your photo, while possible to get an image printed in practically any size you want done, you would have to take it to a custom shop generally to get an odd size printed.  Most places will stick to the conventional aspect ratios and print sizes.  So what is an aspect ratio and why should you care.

Wikipedia of course defines it as “The aspect ratio of an image describes the proportional relationship between its width and its height.”

Sure that’s nice in words, but lets give some visual examples and discuss.

First off, chances are you are shooting with a DSLR, whether it’s a Canon t3i or a Nikon D800 all these cameras share the exact same default aspect ratio, and that is a 3:2 or commonly said “3 to 2”.  That is, there are 3 pixels on the long edge, for every 2 pixels on the short edge.  Below is an image of a rectangle with a 3:2 aspect ratio.

So what does this mean for an image your printing, and what size can you print that at?  Luckily we have super simple math to the rescue.  All you have to do is times each edge by the same number, and that is the print size you can do without cropping your image.  So lets say we wanted in this case our long edge to be 12 inches in our print.  That would be 3×4.  So all we do is 2×4 and we get 8.  We can do an 8×12 print of this image without cropping.

So all you have to do, is put the same number in for x, and get a print with 100% of your image area. If you put 8 in for both edges you get a 24 by 16 inch print! Easy! So what are some other common aspect ratios that are used? We have quite a few.  All starting in the bottom left corner you can see many of the common aspect ratios in use

 

Keep in mind, the vast majority of cameras shoot in a 2:3 aspect ratio, the micro 4/3 systems (such as Panasonic GH2, Olympus E5, and many more) shoot in a 4:3 aspect ratio.  And of course you can create any aspect ratio you want, 1:4 for a very thin image, or 1:2 for a nice rectangle

Any questions feel free to contact us and we’ll answer as soon as possible!

Jonathan and Omnilargess Team

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