How to find out if your camera sensor has dust and clean it

As a wildlife macro photographer, I have learnt the hard way that even a single dust spot on the sensor could, potentially, totally ruin a photograph.

While this is not really a major issue for non-macro photography, over some time, this can impact other genres as well.

For the last few years, I always check for sensor dust before I leave home even when I am not going for a macro session.

I have devised my own method for checking for dust and cleaning it. This is what I will demonstrate here in this video.

First, make sure you have a fully charged battery in the camera. In case we need to clean the sensor, a fully charged battery is required. Also, since this is what I do before I move out to shoot, it is always a good idea to have a fully charged battery anyway.

  1. Make sure you have a fully charged battery
  2. Put the lens you are going to use on the camera body
  3. Stop down to the minimum aperture you would use. Most lenses would stop down to around f/22 or f/32.
  4. Set the camera to manual mode, set the ISO to 100 (base ISO) and shutter speed to around 6 or 8 seconds.
  5. Make sure the camera is not focussed to the light source we will use to check for dust
  6. Release the shutter while waving the camera smoothly around the light source

Once the exposure is done, zoom into the image on the camera LCD and zoom to 100% and scroll around the frame to see if you see any spots. If you do not see any spots, we are done. The sensor is clean.

If you do see spots, then, make a note of where in the frame you see them. This is important since the sensor would have the spots on the opposite sides. For example, if you see a spot on the top of the frame, the spot would be on the bottom of the sensor since the image is flipped. A spot on the left of the frame would imply the right side on the sensor.

I would recommend trying out the exposure with 2 different lenses in case you are not sure if this is dust on the sensor or a spot on the lens.

So, if we find some spots, how do we clean those out?

Firstly, I would recommend you get a LensPen SensorKlear II (https://lenspen.com/product/sensorklear-ii/). This is my general, daily use tool as and when I have sensor dust. Of course, a jet blower is also required and that is the first step to try before using the pen.

Although I do no have a Canon anymore, I will just demonstrate how to do this on a Nikon body. The process itself remains the same across.

Make sure the camera is always pointed down so there is nothing dropping into it…Just as a precaution.

So, let’s start at the first round where we simply use a jet blower to blow any dust out of the sensor and repeat the steps to check for sensor dust. If we do not see the spot anymore, then, we are done. This would be all that would be required on occasion.

Sometimes though, when you change lenses in the field, you might get some dust stuck to the sensor which will not come off using just the blower. This is where the pen comes in.

We follow the same process as cleaning with the blower first, then, we use the pen to gently tap on the sensor to pick up the dust spots. The pen can also be gently swiped across the sensor in case you keep missing the spot. Once this is done, point the camera downwards and use the blower again to clear out any dust.

Now, repeat the process to check for sensor dust and it should be all clear,

For issues even after this process, the only alternative is to use a sensor cleaning liquid along with a sensor swab. Ideally, just take the camera to the service centre if you are not comfortable with the process. I would not recommend wet cleaning on your own unless you feel confident about it.

Although I do have the sensor liquid and the swabs and have tried it a few times, but, there is generally no need for a wet clean in any normal usage.

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