There is a peak of dust inside my lens( Canon 100-400mm 1st gen). And I can find a dot on some of my images( I have no idea why I didn't find it on other images). And is there anything that I can do to remove the dust from my lens? enter image description here

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  • The reason why you only detect the speck of dust on some of your images might be due to your aperture setting. A small aperture (high f-number) results in deeper depth of field, which may make dust more visible. Aug 30, 2021 at 8:52

3 Answers 3


As noted, dust on the front of the lens will almost never show on photos - see this famous LensRental review on Front Element Scratches

Dust on the rear element may make a slight impression - though should be simple enough to clean with a brush &/or air. Dust on the sensor will usually be cleared by the cleaning cycle.

If not, Canon [& Nikon] have a dust 'removal' algorithm that can be employed, using a reference frame for comparison.
Full instructions at Canon KB - Appending Dust Delete Data

For sake of completeness, Nikon's version is called 'Image Dust Off' - Nikon KB - How does 'Image Dust Off' work?


Dust in your lens (especially towards the front side) will likely not produce a dark spot in your image. This is more due to dust specks on the sensor, that come and go (your camera likely cleans the sensor on startup)... or stains, that tend to remain until removed by a manual sensor cleaning, but these show in every shot.


You're mistaking one bit of dust near the front of your lens for the effect of something else.

The dust on the front of your lens is not causing what you are seeing.

Clean your sensor

For more, please see these questions and their answers here at Photography SE:

Dust on Sensor After Many Cleanings DSLR
What to do about persistent dust spots on my DSLR?

See also Roger Cicala of lensrentals.com's excellent blog post, The Apocalypse of Lens Dust

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