Air

While playing with a new (to me via Ebay) I saw the lens extend and realized that the air volume inside the camera must have increased by a cubic inch or two and wondered how the air gets in there. Is there a piston or bellows that repositions to keep the internal volume constant , does the air come in through an internal, filtered, opening or does it come in through whatever cracks and crevices exist? On film cameras a new clean photosensitive surface appears every time you advance the film but with a digital the same surface stays for the life of the camera. I guess I'll have to remember to only turn on the camera in a dust free environment and clean the lens barrel before turning it off. Paranoia makes life more interesting.

Yes, your lens is essentially acting as a bellows bringing air into your camera and sensor. My first couple of DSLRs collected dust and needed frequent sensor cleaning, but later ones that shake the sensor when you turn the camera on are much better. Cleaning the lens barrel can't hurt, but I doubt it will help much. Taking pictures is more interesting than paranoia, IMHO.

You will find it's prudent to inspect and clean your sensor each time you go out, preferably each time you change lenses. A simple blower will do most of the time, but be prepared to use brushes and/or a liquid cleaning method (if you are exposed to salt spray).

 

A lens which lengthens significantly will pump air, which may result in dust on the sensor. More likely, dust will accumulate on internal elements. This has to be pretty bad before it would affect images, and then by scattering light. It looks worse than it is because you're effectively looking through a magnifier. Telescoping surfaces are usually fitted with felt strips, which act as reasonably good air filters. On the whole, it's not something to worry about. Most dust is conveyed to the sensor because it accumulates on the back of the lens and mount in your camera bag.

Nikon Coolpix A so fixed lens. There is a Nikon service facility several towns away so if it gets too bad-.

Disassembling a fixed-lens camera would cost much more than replacing it. The factory usually replaces a camera if it is under warranty. If not, you're on your own.

dust will accumulate on internal elements

 

In my experience, the dust on the sensor is more likely to get in when lenses are changed under dusty conditions.

I had a sensor dust problem with a Panasonic LX-100 which was a disappointment because I thought a non-interchangeable camera would be immune. A Google search quickly educated me it being a common fault with compact zoom cameras. I had it sent away to be fixed which cost a quarter of the initial purchase price. Online fixes seemed to be based on the use of a vacuum cleaner, if it happens again I may give a go with trepidation.

In my experience, the dust on the sensor is more likely to get in when lenses are changed under dusty conditions.

Dust, yes, but for me the problem is mostly lint, which comes from clothing and other fabrics. Dust isn't very sticky and gives up easily with a blower or light brushing, but lint can be very stubborn. My Sony has IBIS and an automatic cleaning cycle, which is only marginally effective. Iceland had dust, and the wind needed to move it around. Particles from microscopic to the size of your little fingernail would go flying. Unfortunately it's hard to see until you start reviewing photos in Lightroom. I strongly recommend clear filters if you go near a beach or anywhere in Iceland (I had to lean on my tripod while holding the camera in Reykjavik).

I had a sensor dust problem with a Panasonic LX-100 which was a disappointment because I thought a non-interchangeable camera would be immune. A Google search quickly educated me it being a common fault with compact zoom cameras. I had it sent away to be fixed which cost a quarter of the initial purchase price. Online fixes seemed to be based on the use of a vacuum cleaner, if it happens again I may give a go with trepidation.

 

This was, in fact, what fixed my dust problem with the Sony RX100 II. At first, canned air that I used made the dust worse. Putting a vacuum cleaner hose on it over the lens assembly removed all the dust on the sensor. I'm a believer.

does the air come in through an internal, filtered, opening

 

- LOL.

What joyful naivety to think that any manufacturer would care so much about the welfare of your sensor!

Maybe an above water housing, similar to an underwater housing.