On 3/02/2016 3:51, clipka wrote:
> Am 03.02.2016 um 00:27 schrieb Zeger Knaepen:
>> Nikon has some weird default settings (like a fixed ISO.. when I use
>> aperture priority, that means I only want to select the aperture, so the
>> default ISO setting should be automatic, in my opinion),
>
> I can't wrap my head around what the ISO setting is for on digital
> cameras anyway. It's not like you can really change the sensor's light
> sensitivity.

it's an amplifier setting. The aperture and shutter time defines how 
much lights enters, which results in a certain voltage in each pixel. 
Changing the ISO changes the amplification of that voltage, so it 
changes the "brightness" of that pixel.
Unfortunately you're also amplifying shot noise.

After that comes the analog to digital conversion (yes, those digital 
camera sensors are analog devices :)), and that's where Canon fails 
miserably: it adds a lot of extra noise, compared to the Sony sensors. 
The result is that with Canon, if you try to brighten the darker parts 
of the image, you're going to see that noise, very soon. With Sony not 
so much, which gives it a far superior dynamic range at lower ISO 
settings (at higher ISOs the shot noise is so high, there's just not 
enough data left for a high dynamic range).

> On a digital camera I'd expect to have a shutter speed setting so I can
> control the movement blur, and an aperture setting so that I can control
> the focal blur, and that's that.

That's possible with so called ISO-less sensors (no sensor is really 
ISO-less yet, but Sony sensors come very close), where it doesn't matter 
if you change the ISO in-camera, or do it digitally afterwards.

There is a good reason why you would do it digitally: with analog 
amplification you risk blowing out the highlights, with digital 
amplification the only problem is you're also amplifying read noise (the 
noise added in the analog-digital conversion, which is very low with 
Sony sensors and relatively high on a Canon sensor).

cu!
-- 
ZK

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