I have a Sony A7S II which I adore; but—like every other camera—it too has its disadvantages. For me, one of those disadvantages is the sensor which is exposed when you switch lenses. And a simple "clean sensor" function in the menu doesn't always help.

This really bugs me. What sensor maintenance routine could relieve me of my sorrow?

EDIT: I'm looking for insights in using a mirrorless camera; i.e., a sensor that is directly exposed to dust, etc. when a lens is not mounted, as opposed to a DSLR where the shutter is closed and the mirror also provides some form of extra protection. General ideas on cleaning a sensor are not part of my interest here.

I would like to inquire on user habits for coping with this specific issue of mirrorless cameras or any other camera where the FF sensor is fully exposed within +/- 1 cm every time you remove a lens.

  • 2
    \$\begingroup\$ Although thar says "DSLR", it is equally applicable to mirrorless interchange lens cameras — I don't think we need two separate questions. \$\endgroup\$
    – mattdm
    Commented Jul 23, 2017 at 14:55
  • 1
    \$\begingroup\$ The steps for avoiding dust are the same...don't change lenses in a dusty environment, clean lenses before and after removal, use sensor shake, are exactly the same. The greater likelihood of dust with a mirrorless is just a tradeoff. \$\endgroup\$
    – user50888
    Commented Jul 23, 2017 at 17:30
  • 1
    \$\begingroup\$ why is the shutter open on a mirrorless camera when changing lenses? \$\endgroup\$
    – ths
    Commented Jul 24, 2017 at 10:18
  • \$\begingroup\$ @ths exactly. you can't close the shutter. what's also the case is that when the camera is on, the sensor is almost like a dust magnet due to static electricity. \$\endgroup\$
    – onimoni
    Commented Jul 24, 2017 at 11:09
  • \$\begingroup\$ There are several questions similar to this one here, but the one listed above is not one of them. \$\endgroup\$
    – Michael C
    Commented Jul 27, 2017 at 21:11

3 Answers 3


There are several things you can do.

Maintain Humidity. The first defense is to keep the equipment in a mildly humidified environment. Normally, we think of moisture being bad for the camera, but dryness intensifies static which causes the dust to attach to parts. Maintaining moderate levels of humidity (30% to 40%) helps dissipate static.

Filter the air in the equipment storage area. Air contains microscopic droplets of oil. These adhere to everything. When a fiber attaches to a surface, like a sensor, what makes it stay there is this oil. You can reduce the presence of oils by using a high quality HEPA air filtration system in your equipment storage area, like a well-sealed closet or cabinet. This will also remove dust from your cabinet.

Remove static using equipment. Static can be removed using sophisticated equipment such as photoionizers and corona discharge. Elecronic companies use these devices to keep sensitive electronics free of static buildup. They are expensive, but if you want the ultimate in sensor maintenance, consider using a de-ionizer. As a cheap alternative, there are anti-static guns such as the "Zerostat".


I really haven't found there's much of a difference between practices that work for dSLR and practices that work for mirrorless. You're just more aware of the "naked" sensor when you work with mirrorless. But all the same techniques apply:

  • Power off to avoid static from charge
  • Change in a clean environment when possible (bag)
  • Changing face-down to let dust fall out
  • Covering the mount with your hand/body cap, whatever until the new lens is to be mounted
  • Use a bulb blower on a regular basis

Etc. It all works pretty much the same way, you just deal with more dust more frequently as a tradeoff of going mirrorless. Sensor cleaning may simply become a more frequent routine. But all the same principles apply and there's really no practical difference just because you're using a different type of camera or full frame vs. crop.


If you use any interchangeable lens digital camera the question isn't if you'll get dust on your sensor, the question is when and how often you'll get dust on your sensor.

The same practices that help extend that interval for cameras with mirrors and shutters also apply to cameras without them.

What to do about persistent dust spots on my DSLR?
How do I avoid dust entering my camera when changing lenses?
Should I be worried about getting dust inside my SLR?
What should I do to avoid switching lenses?
How do I protect my camera in a smoke filled environment?
Shooting on the beach: is it dangerous for my equipment?
Is it safe to change the lens on my new DSLR?
How do I change lenses without damaging my camera?

  • \$\begingroup\$ so, one advice could be to turn the camera off during the switch due to static electricity which lets the sensor act like a dust magnet. \$\endgroup\$
    – onimoni
    Commented Jul 24, 2017 at 11:11

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