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Re: [OM] Raw is ???? & ISO invariance [was GX85 Clarity Slider]

Subject: Re: [OM] Raw is ???? & ISO invariance [was GX85 Clarity Slider]
From: Philippe <photo.philippe.amard@xxxxxxxxx>
Date: Sun, 1 Sep 2019 08:27:16 +0200
In terms of noise, the guy may be right.

Now push the limits, and watch the colours …

Amities

Philippe



> Le 1 sept. 2019 à 07:18, Moose <olymoose@xxxxxxxxx> a écrit :
> 
> On 8/30/2019 3:23 PM, Mike Gordon via olympus wrote:
>> <<<If one uses ACR (LR or PS), distortion correction is not optional.
>> 
>> Yes, no option using ACR to turn off use of metadata corrections.  I haven't 
>> reviewed this in a couple years.  Some corrections in metadata also include 
>> CA and vignetting.  Starting 2014 or slightly before, Panny lenses on Panny 
>> bodies began including  the CA correction metadata.  DXO does NR on the RAW 
>> data pre-conversion, but that is fully user controlled.  Not clear how 
>> clarity could be applied pre-conversion though some other aspects of the 
>> image are baked into the RAW files:
>> 
>> 
>> https://theonlinephotographer.typepad.com/the_online_photographer/2012/10/raw-is-not-raw.html
> 
> While this essay is a great resource, the title is a little misleading. Raw 
> is indeed Raw, but useless until converted into something else. The point is, 
> I think, that the process is more interpretation than conversion. This is 
> rather obvious if one uses different converters on the same Raw file. I can 
> see people wanting to know which conversion is the CORRECT one, but the 
> answer is both none, as there is no inherent converted result in the Raw 
> file, and all.
> 
> The interesting thing that's happened since this essay is improvements in 
> sensor systems such that some cameras may be said to be ISO Invariant (over 
> some range of ISOs). That is to say, the result of shooting at ISO 1600 is 
> identical in shadows/noise to shooting at ISO 200 and increasing luminosity 
> by three stops in processing.
> 
> Quite remarkable is that this is true of some 1" sensor systems, such as the 
> Sony RX100 and Panny ZS200:
> 
> "The ZS200's sensor is essentially ISO invariant, so you can (in most 
> instances) shoot at base ISO and increase the brightness several stops while 
> processing the Raw image, with a minimal noise penalty. By keeping the ISO 
> low the camera captures additional highlight data instead of 'throwing it 
> away' at higher sensitivities by amplifying the signal. You can see similar 
> results from the Sony RX100 IV, which has a more modern CMOS sensor. In turn, 
> this gives some scope for underexposing a low ISO setting to protect 
> highlights, then brightening later."
> 
> They don't mention it, but this also means it will generally be possible to 
> underexpose to maintain usable shutter speeds.
> 
> This change makes some of the conclusions of Ctein's tests rather moot, as 
> one may choose exposure arbitrarily and adjust "exposure point" and curve 
> later, with no IQ penalty.
> 
> Invariably Moose
> 
> -- 
> What if the Hokey Pokey *IS* what it's all about?
> -- 
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