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Dirt on the sensor A7SII


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#1 AlejandroGomez

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Posted 27 April 2017 - 05:27 AM

Hi guys,

 

I was just cleaning the sensor of the A7SII when I saw that a lower aperture you can see all the dirt on the sensor, but if you go up to f1.8 you stop seeing  them.

Maybe the question is stupid but I'm figuring out why this happens, theres some technical explanation ?

 

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E2vCOJu.jpg


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#2 Mark Dunn

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Posted 27 April 2017 - 06:25 AM

Because the dust is actually on the anti-aliasing filter in front of the sensor, it casts a shadow on the sensor.

At large apertures the shadow is spread over a large area. A small aperture casts a smaller, darker shadow.

https://photographyl...mall-apertures/


Edited by Mark Dunn, 27 April 2017 - 06:29 AM.

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#3 AlejandroGomez

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Posted 27 April 2017 - 10:08 AM

Hi Mark,

 

Thank you very much for the explanation and the link!


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#4 Daniel Meier

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Posted 08 May 2017 - 12:43 PM

I used to think that this has to do with the larger depth of field you get with an f/16 compared to say a f/1.8.

Is that true to some degree?


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#5 Mark Dunn

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Posted 08 May 2017 - 01:37 PM

In short, no.

DoF applies to what's in front of the lens.


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