What seems like it could have been an April Fools joke if it had come out a few days sooner, the Lensrentals blog has posted a great (and enlightening) story on something that apparently has happened more than once: somehow, for some reason, a full-sized fly got into a lens, and the entire lens had to be disassembled to remove it. The question is: did it affect image quality?
It’s a situation that’s just plain unexplainable. A fly — yes, what appears to be a fully grown, common housefly — somehow found its way into the inner workings of a Canon 70-200mm f/2.8 IS II lens rented out be Lensrentals. An obvious first thought is that somehow, the fly entered the lens during manufacturing. But, as they point out, this particular lens had been in service for Lens Rentals for over 15 months, so it had to have gotten inside the lens after they purchased it, unless no one had noticed during that time, which is doubtful. The best theory they (and I) can come up with is that a small maggot found itself on the lens, crawled in through the rear element, and settled somewhere in the middle of the lens where, somehow, it had enough food to grow to full size before perishing in an image-stabilized graveyard. Or maybe flies are more flexible than we think, and she just squeezed in there. Who knows.
So begins a twofold saga: what effect this fly had on image quality, and how complicated is it to remove something like this from a modern lens?
According to Lens Rentals’ testing, the fly actually had very, very little effect on image quality until they stopped the lens down to about f/13, at which point, you could start to see a dark shadow on the image. When the lens’ aperture was opened more, you couldn’t see much of an effect.
This is fascinating on so many levels, and is, for me, a little vindicating. I ditched my lens caps years ago for one main reason: speed. I’m OK with my glass getting a little dustier or dirtier for the sake of speed. When I’m shooting an event and want to switch lenses, I don’t have the time to take lens caps off of one lens and put them back on the other before taking my next shot. It slows me down considerably, and the effect that a little extra dust on the lenses has on my final image is close to nothing. Enter the fly. If a full-grown fly inside the lens has such little effect, can you imagine what a few specks of dust on the elements will do? Zilch. Nada.
Vindication at its finest.
The other part stressed in their blog post is this: it’s pretty difficult and labor-intensive to disassemble a lens to clean it. I’m guilty of getting a bill or two back from Nikon for a simple cleaning and being incredibly annoyed at the high cost, but seeing how much this lens had to get disassembled just to clean the elements (or in this case, remove an insect) was enlightening. The newer the lens is, the more sensitive electronics, elements, parts, pieces, and gizmos need to be removed and reassembled flawlessly in order for it to work again. It took over three hours and lots of experience and expensive equipment to do it. It’s certainly something I don’t even want to think about trying myself.
Do you have any lens repair stories that give you the creepy crawlies?