I just bought a Xiaoyi (a cheap GoPro style POV camera made by Xiaomi), and after removing the protective lens sticker I found the lens to have a spot on/in it. It's either an air bubble or fungus, but I'm not sure which, or even whether it is a serious/uncommon enough issue with a camera to warrant demanding a replacement.

Image 1
The bubble like spot appears to the top left of the lens. It is definitely not a reflection of any sort. It has an irregular shape and has a fixed position relative to the lens/camera. It has remained even after cleaning with microfiber cloth that I use to clean my DSLR lens.

Image 2

Also, I'm not able to ascertain whether it is affecting my image quality. The only issues are flaring when pointed towards a light source, but I cannot confirm whether it is being caused by the said defect.

Even having Googled a lot, I've been unable to find a similar looking defect on anyone else's lens (on any camera).

Can someone please confirm what the wierd spot on the lens is? (Please see attached images). And whether it will potentially affect image/video quality? And how I can perhaps definitively confirm what kind of effect the spot is having on my images?

Image 3

Image 4

Thanks a lot.


2 Answers 2


I ended up contacting the manufacturer, who replied the same day and suggested trying to clean the lens with alcohol.

And it worked! The 70% isopropyl rubbing alocohol dissolved what I now believe was residue from the glue of the protective sticker, instantly.

Just using the microfiber without the alcohol wasn't enough to get rid of the glue.

I'm breathing a sigh of relief that it wasn't an air bubble that it looked so much like.

Thanks @Caleb for ruling out fungus and any other serious problem in the meanwhile.

As a side note, using stickers to cover lens seems a pretty bad way to protect them.


It looks more like a bubble or other manufacturing defect than fungus. Fungus is usually more like fine threads, like this:

enter image description here

It also usually takes some time and dampness for fungus to develop. Since it looks like the camera is brand new and packed in original, dry packaging, fungus doesn't seem likely.

(Source: http://www.4photos.de/camera-diy/Lens-Fungus.jpg).

  • 2
    \$\begingroup\$ Hard to tell, but maybe a defect in the application of the lens coating? \$\endgroup\$
    – mattdm
    Apr 7, 2016 at 3:05
  • \$\begingroup\$ Thanks. I understand that this question is quite subjective, but given the size of the bubble relative to the lens, what kind of artifacts/degradation on the photos can be expected? It's a f2.8 155 degree wide angle lens. My main reason of asking is to decide if it's a common defect like small bubbles on older lenses or something potentially more serious that warrants a return \$\endgroup\$
    – flak37
    Apr 7, 2016 at 5:30
  • 2
    \$\begingroup\$ It's quite possible that you might not notice any effect at all. Or, you might see a slightly less sharp image, but since we're talking about a camera that sells for less than $80, I wouldn't necessarily attribute a slightly soft image to the defect. If you really want something "definitive," you should get another copy of the camera without the defect and compare images. Bottom line: If you're unhappy, exchange it; if the images seem fine to you, don't worry about it. \$\endgroup\$
    – Caleb
    Apr 7, 2016 at 6:16

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