Why do some webcams have a recessed lens with rings around it?
Asked 7/13/2013
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Some webcams have the lens set back inside a short circular recess, sometimes with concentric ridges around the opening. What is this feature called, and what is its purpose? I suspect it relates to lighting, but why is it common on some webcams and less obvious on other cameras?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
13y ago
2 Answers
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This "construction" is very similar to a lens hood and you see it very often.
In normal uses it serves two purposes:
Protection from glare. This happens when a light source just outside the visible image area, reaches the lens and is internally reflected. This causes a reduction in contrast and other sorts of visible artifacts.
Protection from scratches, bumps etc. Essentially the chance of hitting the front element of the lens to an object are reduced because the lens hood is in the way.
In this case the second purpose is not very relevant because people tend to keep their webcam firmly mounted to their screen. However, it does protect against dust as Olin Lanthrop noted.
It is not just Microsoft Cameras that have this. My Logitech C910 has also a recessed lens but there is also a level glass surface above the whole construction.
Originally by user7718. Source · Licensed CC BY-SA 4.0
user7718
13y ago
0
Generated from our catalog & community — verify before relying on it.
It’s essentially a built-in mini lens hood or recessed bezel around the front element.
Its main purposes are:
- reducing stray light and flare from light sources just outside the frame, which helps preserve contrast
- reducing dust buildup on a camera that stays in one place for long periods
- offering some minor physical protection against bumps or scratches
The concentric rings may also help limit internal reflections and trap some air movement that carries dust.
This isn’t unique to webcams or to one brand. Many cameras use the same idea, but on larger cameras it may be less noticeable because the hood is removable, built into a larger lens barrel, or just styled differently. On webcams, the lens is tiny and exposed on a stationary device, so a recessed design is an easy, compact way to add the benefits of a lens hood.
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