Dust mite in photographic lens

Adam Lane, a software engineer and amateur photographer, had a rare chance to observe a dust mite eating a small piece of dust inside the lens he uses on his camera. The story was posted on the Canon EOS mailing list (the list no longer exists, and even the archives have disappeared from the net) in March of 1996:

From: Adam Lane

To: eos@avocado.pc.helsinki.fi

Subject: A dust mite!?!

Date: 21 March 1996

This isn't really an EOS issue, but it happened inside of an EOS lens.

Soon after I purchased a 200mm f/2.8 lens last year, it got a really large white spec on one of the optical elements inside. This spec was quite a bit larger than any other piece of fluff in any other lens I own. It was quite disturbing but did not affect the beautiful pictures that this lens took.

Last week, I observed to my horror a dust mite crawling on this very same optical surface.

It walked directly towards the spec, ate it, then walked out of site. I watched it happen in amazement. The lens is pretty clean now except for a single fiber which came from the internal baffle.

The little mite has not reappeared since and I've disinfected quite a bit of stuff becasue of my new discovery about dust mites...I've never ever seen one before this...you sure can see anything when it's inside of a lens!

I can only hope it did not lay eggs inside of my lens.

I hope I can train these suckers so that I can sell my new internal lens cleaning technology.

Sick.

Adam followed up by taking a picture of another creature of the same species in late April 1996 (the original hero was probably killed).

The photo is © Copyright Adam Lane, 1996.This Dust Mite not to be used for personal gain.

When asked about the size of the beast, he wrote:

The actual size is a bit smaller than most "period" punctuation marks. About the size of a single pixel. A smallish grain of sand. Very hard to locate under the viewfinder; very hard to focus. I'm surprised I got any detail.

The lens was about 10x! a 4x6 print increases this to 60x! The cropped image displayed on a monitor makes it close to 100x! Only a guesstimate.

The following photographic equipment was used:

Canon 1n

ML-3 and 540EZ flash units

100mm f/2.8 Macro lens set at 1:1 with the following attachments in order from lens to camera body...

25mm extension tube

Canon 2x TC

12mm extension tube

Canon 1.4x TC

Cambron 2x TCRoyal Gold 100 film

1/250 sec

f/8

Reduced to black & white to save disk space...there's really very little color to see.

A comment sent by Michael a. Deutsch:

As a professional entomologist, I can tell you that the dust mite is not an insect. It is an arthropod but is not in the class Insecta. It is in the class Arachnida...spiders, ticks, mites and other creatures that have 8 or more legs as adults. Adult insects, if they have legs, will have only 3 pair or 6 legs.

Dust mites have been associated with human allergies and along with the cockroach,are being studied as possible causes or triggers for asthma attacks, especially in young children.

A comment sent by Thorkil E Hallas:

The mite designated as a house dust mite is not such a species. It's an house-mite, by name Glycyphagus domesticus. You can read about it and see its picture in Hallas T, Mourier H, Jansson L: Elintarviketuholaiset (1987) p.79,81. They are not uncommon in photograpjic equipment stored in humid houses.

[Ed. note: that book is in the Finnish language.]