Relation between dust and aperture setting

Started Mar 30, 2014 | Questions thread
kentak Junior Member • Posts: 39
Re: Relation between dust and aperture setting

SushiEater wrote:

Ignoring diffraction effects and extraordinary things that might happen in space with large bodies like planets, neither of which I think we're talking about here, light in a constant medium (like air) travels in a straight line. As long as you insist otherwise, it is not worth discussing further with you.

If you were correct than light shining on the object would create well dined shadow. But it doesn't.

Even laser shined on the moon would produced very large circle there. Not so straight line, is it.

If you want to share a reference on the ball and disk that shows light bends and it's not purely a diffraction effect, then folks could take a look.

Oh, by the way why do YOU think that a small aperture makes dust particles more visible if it's not for the reasons I've outlined.

For the same reason you see sharper when you squint.

jfriend00's answer and reasoning are correct.

Here is a link that shows an explanatory diagram.

dust and aperture

It's because dust lies on the filters above the actual photosites that aperture makes a difference--due to light rays coming more directly at small apertures and from wider angles at large apertures.

If dust were able to lie directly on the sensor, thus blocking all light to given pixels, then aperture would make little or no difference and dust would be visible and distinct no matter the aperture.

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