Understanding Aspect Ratio in Photography

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Understanding Aspect Ratio in Photography

This tutorial is the first in a multi-part series covering Aspect Ratio, Resolution, and Cropping and Resizing.

5×7.  8×10.  4×6.  12×12.  What do these numbers have in common?

They are all sizes that we commonly use for printing images, right?  They are also Aspect Ratios.

Aspect ratio is the proportion of an image’s height to its width.  Most cameras have the ability to produce images in one and only one aspect ratio.  And for most of us with SLRs this ratio is 2:3.  That means that the height of the camera’s images is 2/3s of the width.

That’s simple enough, right?  Next, let’s replace “units” with “inches.”  We can print the image above as 2×3 inches.  But who wants a wallet size of this photo?  Let’s double the size to make it 4 inches tall by 6 inches wide.  Still not big enough?  Let’s double it again, to 8 inches tall by 12 inches wide.

Wait a minute.  You skipped right over 8×10.  That’s the size I want for printing this image.

The aspect ratio of an 8×10 is 4:5.  That means that it is 4 units high by 5 units across.  How do I know?  I divided 8 by 2 (=4) and 10 by 2 (=5).  4:5 is not the same as 2:3.  Who said photography wasn’t a science?  This stuff takes some thought, until it clicks for you.

So how do you get an 8×10 from an 8×12?  Well, you have to crop those extra two inches off the side, right?  And you are going to lose 2 inches of your image.  There is no way to avoid that.

What happens if you want to go from a 4×6 to a 5×7? Can’t you just add an extra inch on to each side?  No, not unless you want to distort your image.  Adding an inch to the width is going to increase the width by 1/6, right?  But adding an inch to the height it going to increase your height by 1/4.

That would take this perfect square and circle in a 4×6:

And turn them into a rectangle and oval in this 5×7:

Imagine what your clients would think if they were all stretched out like that….

This is the answer to that age old digital photography question, “Why do I have to crop off part of my image if I’m going from a small photo (4×6) to a larger one (8×10)?”

It’s not about the size of the photo, it’s about the aspect ratio.

Another way to think about this is to compare a 4×6 to a 4×5 (also called a “baby” 8×10).  The 4×6 is always going to be wider, no matter now many times you double the size of the image.

Now that we’ve covered that, let’s list the common aspect ratios and their corresponding print sizes.

  • 2:3 – 2×3, 4×6, 8×12, 16×24, etc.
  • 4:5 – 4×5, 8×10, 16×20, 24×30, etc.
  • 5:7 – 5×7, and that’s about it.
  • 1:1 – a square.  Common sizes are 5×5, 12×12, 20×20

To avoid cropping when changing the size of a photo, remember to increase the size of the image by multiplying both the height and the width by the same number.  Or to decrease the size without losing part of your image, divide both the height and the width by the same number.

Next is this series is an article about Resolution in digital photography.

Want more information like this?  Take one of Jodi’s online Photoshop classes or Erin’s online Elements classes offered by MCP Actions.  Erin can also be found at Texas Chicks Blogs and Pics, where she documents her photography journey and caters to the Photoshop Elements crowd.

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 Understanding Aspect Ratio in Photography

Erin Peloquin

Erin is Jodi's second shooter here at MCP Actions. She converts Photoshop Actions to work in Elements, creates Lightroom presets, and teaches our workshops. Her photography studio is Time in a Camera.

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12 Comments and 2 Replies



  1. 1
    Cathy Kurtz says:

    What would be an interesting discussion is any tips you have for shooting, keeping all these aspect ratios in mind! If you shoot without knowing what aspect you’ll use for printing, do you just plan on leaving extra room on the sides in case you have to cut off 2″ off the side of that 4X6 to print an 8X10? Is there a general rule of thumb for this? I usually know how my prints will be used but I have goofed up before and taken our family’s picture and used the full width of my frame, only later to figure out that I couldn’t print an 8X10 without either cutting someone off, or having 1″ blank space at the top and bottom! (I ended up making a collage instead.. lol) But I learned my lesson. But I’d love to hear more about what you do, since you may not know what clients will order, right?

  2. 2
    Anke Turco says:

    exactly what Cathy said! That is often a problem for me also. I know the easiest way is to pull back a bit, but I often don’t keep that in mind.. how do you avoid that problem?

  3. 3
    kathy pilato says:

    thank you, thank you, thank you

  4. 4
    Jen A says:

    In response to Cathy and Anke…you have to shoot keeping all the ratios in mind which means pull back at least a little. You never know what size your clients are going to want and you need to be able to give them whatever size they choose. You can gently steer them in a certain direction but as an example – a lot of people like 8×10′s. If you shoot everything for a 2:3 print, at some point you’re going to have to crop to 8×10 and you’re not going to be happy with it. If you allow the extra room in advance, you can always crop in closer at any ratio later :) Hope that helps.

    Also, in the article where she mentions the 1:1 ratio – I believe the last number should be 20×20 – not 20×12 – don’t want anyone to be confused by a typo!

  5. 5
    Donna Jones says:

    I love the Fusion Desire edit! Second would be the Frosted Memories. MCP is the best place to learn and enjoy photography! I’ve taught a few photo classes and always struggle with how to explain aspect ratio….you did it perfectly!
    In answer to the two comments I see posted…just back up a little to leave space for cropping…after 20 years it has become a permanent habit for me and will for you too!Frame, backup, shoot!

  6. 6
    Melissa Davis says:

    I work at a professional photo lab. Aspect Ratio is something that we discuss with customers every day.

    I agree that the easiest way to adjust for printing aspect ratios is to shoot wider with extra room around your subject. There are grids that you can have added to the view finder of your camera. These give you an idea of how to frame for certain sized prints.

  7. 7
    Kelly says:

    Aspect ratios are strange. Example: 35mm film is 2:3 aspect ratio, but most photo paper and supplies are sold 8×10 or 11×14. Neither of which work!
    Where I get stuck is what size crop to give a client if I sell digital negatives. They’re not going to understand aspect ratio and I’m afraid of what Walmart will decide to crop. So far, my only solution is to make digital negatives expensive enough to be a deterent. Maybe an instruction guide should be included as well…
    PS. Anyone notice how hard it is to find affordable 8×12 frames?

  8. 8
    Anke Turco says:

    thanks for the pointers! Pulling back is pretty much what I have been doing (although I tend to forget at times :)) What size do you use to present your photos to your clients though? I pretty much crop mine to 5 x7. Is that what everybody does?
    Thanks for the great post!!!!

  9. 9
    wow says:

    Kelly – don’t underestimate the brains your clients have. That’s mistake number one. Mistake number two, SELL THOSE FILES! That’s pure profit with no work involved. Mistake number 3..worrying about custom frames and the cost.

  10. 10
    Zero Equals Infinity says:

    I generally don’t worry about aspect ratio. I crop or don’t to obtain the image that I want, and the matting and framing will be customized as necessary.

    With matting it is often preferred to have a wider bottom than the other three sides. This also affords you with the ability to use a standard frame size even when the aspect ratio of your image does not fit the standard frame. Simply decide on the overall dimensions of a standard frame which requires an aesthetically acceptable / pleasing width of the bottom side of the mat. Cut the mat to the opening required for your image with the non-bottom sides all of equal width, and allow the bottom to be wider. If you feel the bottom is excessively wide, cut a small opening and put a title for your print in it. Voila!

  11. 11
    Jan says:

    Thanks for helping me understand aspect ratio. This is the best explanation I’ve ever seen. Simple. I think I may finally have this figured out!

  12. 12
    Jennifer says:

    Okay, I understand aspect ratios and crop sizes, but I have a further question on what to do for clients. Obviously, I try to compose a great shot in camera and do pretty well, however, sometimes when I’m cropping in PS, I might need to recrop slightly for the rule of third or the golden rule (or any other crop lines I might want to do). Now this is fine when I’m on a 2:3 aspect ratio and I’m fine with showing clients this, however, what do you do for different aspect ratios. When I am on the Rule of Thirds and have it perfect for a 2:3 aspect ratio, that’s going to change when they want it printed on an 8×10 – for a 4:5 ratio. So, if I’m printing, that’s not as big of problem because I can adjust, but if I’m giving digital files…should I give them different crops or is there a better way. Do I just give them the full frame? Help! :)



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