How many stops is the built-in ND filter? - General Help and Assistance on using CHDK stable releases - CHDK Forum

How many stops is the built-in ND filter?

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Offline gjb

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How many stops is the built-in ND filter?
« on: 09 / July / 2012, 07:41:21 »
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Hi

Does anyone know how many f-stops the built-in ND filter in an SD-series camera is please? The exactly model is PowerShot SD800 IS.

Thanks

Re: How many stops is the built-in ND filter?
« Reply #1 on: 09 / July / 2012, 09:46:01 »

Does anyone know how many f-stops the built-in ND filter in an SD-series camera is please? The exactly model is PowerShot SD800 IS.


Looks like three, an exposure  factor of eight.

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Offline gjb

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Re: How many stops is the built-in ND filter?
« Reply #2 on: 09 / July / 2012, 16:36:57 »
Looks like three, an exposure  factor of eight.

Thanks. I've done some more testing and it seems to be 2 2/3 stops (f2.8 to f7.1), so I guess this could vary between camera models.

Re: How many stops is the built-in ND filter?
« Reply #3 on: 09 / July / 2012, 19:05:59 »
I've done some more testing and it seems to be 2 2/3 stops (f2.8 to f7.1), so I guess this could vary between camera models.

I was simply going from the CHDK code which I can tell is not completely accurate.

Not only does it vary between camera models but also between firmware versions.
The small differences have no practical significance.


David

 

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