Thanks (I think) for that reference Moose.
Unfortunately I don't think it addresses increased noise from long
exposures, ok the relative shot noise increases when the amount of light
hitting the sensor is low and you tend to use longer exposures when the
light level is low, but this is also the time when you also might opt for
high ISO. No mention of increased noise at long exposures due to heating of
the sensor. Also no mention of dark frame subtraction for long exposures
which only has relevance if particular pixels are noisier than others (in
fact producing a signal when NO light hits them), this is not relevant to
shot noise which will be randomly distributed across the frame from one
exposure to another.
Seems like there may be no general rules which can be employed so it
probably requires some experimentation.
How about photographing a blank sky (might as well put it well out of focus)
at different ISOs and measuring the difference in image noise ?
Is there any software which can give a measure of the noise in an image ? I
imagine noise reduction software can do this.
...Wayne
-----Original Message-----
From: olympus
[mailto:olympus-bounces+wayne.harridge=structuregraphs.com@xxxxxxxxxxxxxxxxx
] On Behalf Of Moose
Sent: Tuesday, 22 September 2015 4:08 AM
To: Olympus Camera Discussion <olympus@xxxxxxxxxxxxxxxxx>
Subject: Re: [OM] Digital Noise
On 9/21/2015 4:38 AM, Wayne Harridge wrote:
> Any theories ?
>
> 1. Noise increases as ISO increases
> 2. Noise increases as exposure time increases
>
> So which option gives the least noise ?
>
> a. 16 minute exposure @ISO 100
> b. 1 minute exposure @ISO 1600
>
> What is the answer of an E-1 ?
> How about E-M5 ?
>
> How do you find the optimum (lowest noise) ISO/exposure balance ?
Read this, then tell us. :-)
<http://www.dpreview.com/articles/8189925268/what-s-that-noise-shedding-some
-light-on-the-sources-of-noise>
Oh So Quiet Moose
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What if the Hokey Pokey *IS* what it's all about?
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