Macrophotography: Measuring Magnification

Magnification is the differentiating factor between macrophotography and closeup work. Anything equal to or higher than 1x magnification (or 1:1 which means the image is the same size as the object being photographed), this is considered to be a macro. Anything lower than 1x magnification is considered to be a closeup.

To measure the magnification of your macro gear setup, get a ruler with mm scale. Take a picture of the ruler focusing on the mm scale. Ensure that you will be able to get a measurement of the image's width in mm. Now, get the width size of your digital camera's sensor. For example, for a Canon 40D, it's 22.2mm. A great resource for this information is Digital Photography Review. Now, divide your sensor's width to that of the width in mm from your image.

As an example, based on my test image below, the width's size is approximately 13mm. Using the Canon 40D sensor size, we divide 22.2mm with 13mm.


Click image to enlarge.

22.2/13 = 1.7. As a result, the magnification of this macro gear setup is about 1.7:1 or 1.7x magnification.

Another example based on my test image below, the width's size is approximately 6mm.


Click image to enlarge.

22.2/6 = 3.7. This is equivalent to 3.7:1 or 3.7x magnification. This is already enough to make a tight portrait of an ant or fly.