Microscopes for Dummies

Compound microscope

Here at the Antisocial Network our researchers have noticed that a dead giveaway we've pinged another freelancing fake is finding a nonsensical answer to a nonsensical question. You know, like someone who says "chlorophyll" in answering the question "What makes the sky green?" The sky's not green, and even if it were it wouldn't be because of chlorophyll... That's how we spotted an old friend in a new venue not long ago: she's sixteen-time winner of our coveted DotD award Joan Whetzel, who we happened upon answering the nonsense question "What Is a Depth of Field Microscope?"¹ for Demand Media's Techwalla.com website (we have to assume that Techwalla thinks Joan's contribution is a "product review" because most or all of the employees are Demand Media drones with little or no technical experience beyond holding their iPhones in that stupid flat position to use them as speakerphones... but we digress).

The problem with Joan's post? There's no such thing as a "depth of field microscope." Depth of field is a property of optical devices such as cameras, telescopes, and microscopes. It is not, however, a "type" of microscope.

Here's where Joan went all cattywampus with her post. She opens by claiming that "Microscopes contain two lenses, positioned at opposite ends of a cylinder..."; ...which is a gross oversimplification. A microscope comprises an eyepiece and an objective, but those parts are almost always compound optics containing multiple lenses; not just one each. Already Whetzel's demonstrated her ignorance. After transcribing (incorrectly, as usual) additional information specific to one microscope and pretending it's a general observation, Joan gets to the meat of her stupidity: "Depth of field describes a layer that is in focus. The layer grows thinner with increased magnification."

Whoa, Joanie, be careful now: you almost got something right! In point of fact, the depth of field is the distance between the nearest and farthest objects in an image that are in focus. And believe it or not, the second half of Whetzel's statement is (almost) true: given a constant aperture, depth of field is inversely proportional to magnification. Guess what: even a blind pig finds an acorn once in a while!

We would have rather that someone – preferably a would-be freelancer who knows a microscope from an acorn – gently explain that there is no such thing as a "depth of field microscope" before going on to correctly define depth of field as the term is used in microscopy. To do so, however, would require at least some grasp of optics and at least a few minutes of hands-on experience with a microscope. It's clear Joan lacks both, which is why she's receiving Dumbass of the Day award number seventeen. Sigh.

¹ The original has been deleted by Leaf Group, but may still be accessible viathe Wayback machine at archive.org. Its URL was    techwalla.com/content/depth-field-microscope_ [note: there's a copy at sycellphone.blogspot.com/2011/06/what-is-depth-of-field-microscope.html]

copyright © 2016-2022 scmrak

SI - OPTICS