Spider Saturday: Portraying Size

One of the difficulties nature photographers have is providing the viewer with a sense of size. Take a photo of a building and the viewer knows how large it is based on their knowledge of the average height of the building’s floors. But take a photo of an insect sitting on a rock and the viewer can only guess how large or small it is. Case in point: last weekend in the Mojave National Preserve I photographed two spiders, but can you tell which one is larger in real life?

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Plectreuridae Plectreurys

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Unidentified orb weaver

If you guessed that the dark gray spider was bigger, you’re right. But how much bigger? And how small is the light tan orb weaver spider? Without any reference point or knowledge of these two spiders, it’s near impossible. The internet can do a lot of things, but showing objects at actual size is also near impossible due to differences of screen resolution. To remedy this, most scientific photographers provide small keys to reference the size of their specimens. I too bring a long a small ruler to measure specimens when I’m out photographing insects because it is so easy to lose touch with their true size after taking the photos. I measured both of these spiders in the field. The body of the dark gray spider (Plectreuridae Plectreurys) measures 13mm while the body of the unidentified orb weaver measures a little less than 1 mm. Less than one millimeter. Here’s a size comparison of the two spiders:

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Even with the knowledge of the size in millimeters, it still might be difficult to grasp how small insects can get, the orb weaver in particular. It might be easier to compare the spider to something many of you might have in your pocket right now: a dime. I photographed a dime using my Canon 65mm F/2.8 MPE lens, which can photograph up to five times life size. The following images are not cropped.

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A modern US dime measures a little under 18mm in diameter, a little larger than the body of the Plectreuridae Plectreurys. This first photo was taken at the minimum magnification of 1x (or 1:1) for the lens. Lets get closer...

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At 2x (2:1), the lens can only capture about a fourth of the dime.

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This is the dime at 3x (3:1), about the same focal length I used to photograph the orb weaver above

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At 4x (4:1), the nicks and grime become canyons and lakes.

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At 5x (5:1), we have reached the maximum magnification of the lens. The height of the D on the dime is slightly smaller than the body length of the orb weave spider.

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  • Moe
    Very cool post. And what a small spider! I would have had no idea how small he actually was (even when you mentioned 1mm) until you referenced it with the dime.

    And I want your lens. Great detail up close!
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