Guidelines for Cropping Photos

Control Aspect Ratio

Improve the proportions of your images by cropping photos to change aspect ratio

Aspect ratio, the ratio of image width to image height, has a strong influence on the presentation and perceptions of your photographs. Yet, if you don't give thought to this key proportion, then camera, monitor, and print paper manufacturers control it for you. 

Ultimately, you will want to select an aspect ratio that is suited to a combination of your creative expression needs and the constraints of your presentation format. For example, if you are photographing for a slide show displayed on digital high definition televisions and you want your images to fill the screen, you will need to crop your photos to a 16:9 aspect ratio. On the other hand, your creative vision may guide you to use a square format regardless of shape of the screen.

To arm you with the information to make the best decisions for cropping photos, this page explores a variety or drivers for selecting aspect ratio.

Native Camera Aspect Ratios

The first guidelines for selecting aspect ratio come from our cameras. Specifically, the format of the image sensor or the film frame provides "out-of-the-box" proportions that govern the ultimate print size and, in many cases, govern commercial print paper sizes. If you assume that the camera sensor or film has the right aspect ratio, then you can avoid cropping photos altogether, and rely on simple enlargements.

Here are some of the aspect ratios governed by camera format.  Note how the first two of these are driven by film formats, not digital.

The "Aspect Ratio" column shows the ratios as if the image were in landscape format, while the "Size" column reflects portrait orientation. Note in the tables the inclusion of a simple "Ratio" to make it easy to compare the various shapes.

The 35 Millimeter Standard

35 millimeter film uses a frame size of 36 mm x 24 mm, approximately 1.5 x 1.0 inches, for a 3:2 aspect ratio. Many high-end digital SLR's (DSLR) use the same aspect ratio, although their sensor sizes may vary from about two-thirds the size to a full 36 mm x 24 mm.  In the list of common paper sizes, we see a number of print paper sizes derived from the 35 mm aspect ratio, as illustrated below - and these are great because they minimize the need for cropping photos.

Paper Size	Aspect Ratio	Ratio	Comments
35 mm std.	3:2	1.5	The 36 mm x 24 mm film standard
3-1/2" x 5"	10:7	1.43	A bit squarer than 3:2, but a popular size for many years, as driven driven by commercial film developers
4" x 6"	3:2	1.5	Great because it is a bit larger than 3-1/2 x 5, and doesn't require cropping your DSLR photos
5" x 7"	7:5	1.4	Also a bit squarer than 3:2, but a popular next step in size over the 3-1/2 x 5 paper
12" x 18"	3:2	1.5	Larger size offered by on-line printers, such as snapfish.com, and not requiring any copying
13" x 19"	19:13	1.46	Close to 3:2; used by large format printers such as the HP B8850
20" x 30"	3:2	1.5	Larger size offered by on-line printers and not requiring any copying

 

Medium Format Film and Digital Cameras

Medium format cameras, mainly 2-1/4" x 2-1/4", but sometimes 2-1/4" x 3-1/4", seem to have had little influence on common print paper sizes, at least in the US.

Negative Size	Aspect Ratio	Ratio	Comments
2-1/4" x 2-1/4"	1:1	1	Square format leads to paper trimming or cropping photos with standard paper sizes
2-1/4" x 3-1/4"	13:9	1.44	Close to 35 mm film ratio

Large Format View Camera Standards

Typical film view camera sizes, 4" x 5", 5" x 7", and 8" x 10", drive standard print paper sizes for darkroom uses. 

Paper Size	Aspect Ratio	Ratio	Comments
4" x 5"	5:4	1.25	Size of a contact print from a 4" x 5" negative
5" x 7"	7:5	1.4	As this is closer to 35 mm proportions, it is seen as seen as a good adjustment step for those moving from 35 mm to view camera formats
8" x 10"	5:4	1.25	Enlargement size for 4" x 5" cameras, or contact print for 8" x 10" cameras
11" x 14"	14:11	1.27	Just a fraction less square for 4x5 and 8x10 film enlargements, so not much cropping required. For 5x7 negatives, requires more cropping.
16" x 20"	5:4	1.25	Good for enlargements from 4x5 and 8x10 negatives

 

The 4:3 Standard

Point-and-shoot and "prosumer" digital cameras often use an image sensor with a 4:3 aspect ratio, which used to be standard television proportions. While this ratio is good for monitor and electronic picture frame display, it doesn't match any standard print paper sizes, so it always requires cropping photos when printing.

Example Sensor Size	Aspect Ratio	Ratio	Comments
2560 x 1920 Pixels	4:3	1.33	Minolta Dimage 7Hi sensor

 

Monitor & Electronic Frame Aspect Ratios

Television monitors, especially the new high-definition (HDTV) monitors, are an effective medium for presenting your images to family and friends, although they both present a few challenges.

Until the advent of the wide flat-screen TV, CRT-based TV's and computer monitors always used a 4:3 aspect ratio.  This is great if your camera also has a 4:3 sensor, except that standard CRT TV delivers poor image quality. If you can put your LCD computer monitor in front of friends, that works much better.

Wide-screen TV's deliver better image quality, but use an aspect ratio of 16:9. With these, regardless of which type of camera you have, you will choose one of these display options: displaying your photos with blank screen on either side, stretching your photos to fill the frame, or cropping photos to match the monitor proportions.

Although monitors have gone wide, electronic picture frames have, until recently, tended to stick with the 4:3 aspect ratio, which is great for the majority of non-DSLR cameras.

Display Type	Aspect Ratio	Ratio	Comments
Standard CRT	4:3	1.33	Hard to get good image quality, as these are usually low resolution
Digital Frame	4:3	1.33	Get 640 x 480 pixels minimum for acceptable image quality
Wide Digital Frame	5:3	1.67	Slightly less wide than wide screen. Sometimes called 16:9, although actually 15:9 (= 5:3) at 800 x 640 pixels. As of 2009, this is an evolving market, so these ratios may change in the future
HDTV (U.S.)	16:9	1.78	Also used for European digital television
Academy Flat	1.85:1	1.85	For wide-screen motion pictures
Anamorphic Scope	2.35:1	2.35	For wide-screen motion pictures: Panavision or Cinemascope

In all cases, though, when your photos are in portrait format, you are faced with the choice of either displaying blank screen either side of the photo (not so bad, really) or cropping photos to fit the horizontal format.

Printer Paper Sizes

Square

The Golden Ratio

At least as early as the Renaissance, artists have used the golden ratio to guide the proportions of their paintings. The golden ratio, approximately 1.618:1, fits between the 35 mm and wide screen. TV standards.

Many of the example images in ImproveYourDP use the golden ratio, as seen in the House on Mirror Lake.

Ultimately, you choose the final aspect ratio of your prints or photo displays. No single aspect ratio is better than another, although you may develop a preference for cropping photos to a specific ratio that suits your style in the majority of cases.