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To investigate sensor dust, perform the following test:

• Close your aperture as much as possible (high F-number). This makes the sensor dust more visible.


• Increase the focal length as much as possible (zoom in).


• Focus on infinity (not sure if the focus part is actually necessary) on a bright, uniform background. I've found that the blue sky works well for this purpose.

When I had horrible sensor dust, my test photo looked like this (images darkened to enhance visibility of sensor dust):

After professional sensor cleaning through a photography shop in my area, it was almost completely gone:

In the former case, there was dust visible on most of my photos, in particular in the sky. In the latter case, I have not noticed any dust.

Both photos taken at F/40 with 200 mm focal length (Sony α6000).

There's probably something on the sensor - maybe a dust particle.

You can check if the Canon camera has a sensor cleaning option and use it or take the camera to a local repair shop and have the sensor cleaned there.

Or you can clean the sensor yourself, but I wouldn't recommend it, as you are a beginner.

Dust on the sensor, as other answers have suggested, is a strong possibility. Another possibility is dust on the rear element of the lens. If you change to a different lens and the spots go away, that's the culprit. If they're still there, it's the sensor. If it's the lens, a cleaning cloth and a gentle touch will fix it.

Also, try to avoid using very small apertures (f/11 or f/16 or even higher) until you have an opportunity to clean the sensor or get it cleaned - small apertures make dust particles on the sensor far more pronounced.

If you see the same spots on all photo this is definitely dust spot on sensor. To be precise this dust do not touch sensor itself but the filters in front of the sensor.

To clean this you can try few ways.

1. Use the "Clean sensor" function if your camera as this function. This will vibrate the sensor and try to get rid of dust


2. Use blower to try to remove the dust. This should be done on
   switched on camera and directed down the lens mount (to be sure
   dust will go outside the body). Also you can activate mirror lockup
   to have better access to the sensor. And also its good camera to be in liveview mode.


3. Send your camera to repair shop for cleaning.


4. And last, try to clean the sensor by yourself.

Try this:

1. Open your best and just cleaned lenses to its max. aperture (the
   lower the f-stop, the bigger the aperture).


2. Manually focus to the shortest distance available on the lens.


3. Find well and evenly lighted white wall, move away from the
   wall until it’s quite blurry in the viewfinder. Take a few photos in
   raw.


4. Go to your editing (developing) software and view the raws at 1:1
   (real pixel size). To see the whole photo, you will have to move it.


5. Anything that you see, depending on color and shape, is either dust
   and other particles on the sensor or a dead pixel in the sensor.

Tip: don’t forget to move the image and recheck if a dead pixel is suspected, monitors are prone to have dead pixels too and you could just spotted a dead pixel in your monitor not your camera.

It's more than likely a pics of dirt or dust on your sensor. You can get special cleaning tools on eBay that doesn't cost that much. And there's plenty of videos showing you how to clean it be very careful though!