We’ve recently cleaned a sensor on an A7III. The sensor has bad dust and a smeared finger mark on the surface! The resulting image with photography and video will give you an unclear image, so once we serviced the camera and cleaned the sensor, we put on a 50mm lens tested with a few test shots at the sky and the marks had been successfully removed.
Sensors in cameras can become dirty by using lenses that lack that special weather coating and seals (Zeiss and Canon lenses do have this but some manufacturers such as Samyang, Rokinon and Sigma Art range are still ignoring this key feature) and dust tends to find it’s way around and onto the surface of the sensor.
We absolutely advise that you DO NOT attempt to clean a sensor yourself! This is highly risky, and without the training and expertise, you can end up scratching the sensor surface.
How to check if your sensor has dust:
- Set your camera on Aperture Priority Mode.
- Set your metering mode to Matrix/Evaluative Metering.
- Set your camera ISO to the lowest number such as ISO 100 or 200.
- Turn off Auto ISO.
- Turn off autofocus and set your lens on manual focus.
- Set your aperture to the largest number available for your lens by rotating the camera dial. For example, the minimum aperture on the Nikon 50mm f/1.4G is f/16, so if I were shooting with this lens, I would set my aperture to f/16.
- If you are outside, point your camera up at the clear blue sky and take a picture. Make sure that your focus is way off (completely out of focus) – that way only dust particles will be visible.
- Zoom in on the image (rear camera LCD), scroll from left to right and top to bottom all over the image and see if you can find any dark spots.
- If you cannot see any, your sensor is clean. If you see dark spots like in the above example, then your sensor has dust on it.