ISO (Traditional) and ISO (digital) (Page 5): Indeed. Those who are not interested are not compelled to read let alone respond to the thread. Thank you, as always, for your extremely...

Blenheim Orange Loc: Michigan

Ysarex wrote:

It's never a bad idea to understand how things work.

Indeed. Those who are not interested are not compelled to read let alone respond to the thread.

Thank you, as always, for your extremely valuable contributions here.

selmslie Loc: Fernandina Beach, FL, USA

selmslie wrote:

Just keep in mind the ultimate warning about ETTR:

Foe the rest of the story see Exposing to the Right Explained in Photography Life.

Ysarex Loc: St. Louis

Blenheim Orange wrote:

Indeed. Those who are not interested are not compelled to read let alone respond to the thread.

Thank you, as always, for your extremely valuable contributions here.

Thanks.

Doyle Thomas Loc: Vancouver Washington ~ USA

define DR = dynamic range. some may not know.

selmslie Loc: Fernandina Beach, FL, USA

Doyle Thomas wrote:

define DR = dynamic range. some may not know.

There are five of them - the scene, the sensor, the raw data, the print and the display device.

Add to that the DR you want to keep since you may not be able to have everything in one shot.

This may go well beyond the scope of this thread.

Jack 13088 Loc: Central NY

Jrhoffman75 wrote:

…Sunny 16 seems to always work.

There is a reason for that. For the measurement standards are adjust to correspond to 18% gray being middle gray at Sunny 16. Not particularly useful for a real life scene but it is standard. A meter reading is only a nice starting point to nailing the exposure. I try for max exposure to just avoid blowing out the brightest high lite. And I do know that “blow out is a film term. Max ISO is for marketers not photographers. I do notice that the amount of color noise at “max ISO” is more or less consistent for Nikon cameras over the years. Which is nice.

Badgertale Loc: Albuquerque, New Mexico, USA

Digital ISO is simply gain. That's about it.

Ysarex Loc: St. Louis

Badgertale wrote:

Digital ISO is simply gain. That's about it.

How about a definition of gain? I search and find this: "Gain is a measure of the ability of a two-port circuit (often an amplifier) to increase the power or amplitude of a signal from the input to the output port by adding energy converted from some power supply to the signal." Is that what you mean by gain? Digital ISO in cameras does that. But how do you account for ISO when it works differently and doesn't do that?

Badgertale Loc: Albuquerque, New Mexico, USA

...account for ISO when it works differently and doesn't do that?...

Keep searching. I think you are on to something! :0)

Ysarex Loc: St. Louis

Badgertale wrote:

...account for ISO when it works differently and doesn't do that?..

For example when a digital camera applies an ISO change while converting the raw data to a JPEG and doesn't effect the ISO change by amplifying the sensor signal. How is that gain?

TriX Loc: Raleigh, NC

Doyle Thomas wrote:

define DR = dynamic range. some may not know.

Dynamic range in photography describes the ratio, in stops, between the maximum and minimum measurable, recordable or displayable light intensities. In terms of digital cameras, it is bounded on the upper end (max intensity) when the most significant bit (MSB) of the A/D converter (digitizer) is set, and on the lower end (minimum intensity) by the noise of the system and the error in digitizing (and of course, the resolution of the digitizer)

selmslie Loc: Fernandina Beach, FL, USA

TriX wrote:

Dynamic range in photography describes the ratio, in stops, between the maximum and minimum measurable, recordable or displayable light intensities. In terms of digital cameras, it is bounded on the upper end (max intensity) when the most significant bit (MSB) of the A/D converter (digitizer) is set, and on the lower end (minimum intensity) by the noise of the system and the error in digitizing (and of course, the resolution of the digitizer)

Do you really want to go where angels fear to tread? There seems to be some disagreement about how to determine DR.

Even when using "derived from DxOMark data", Photons to Photos shows a DR of about 11.6 stops at ISO 100:

when DxOMark shows a DR of 14.36:

Why is there a 2.76 stop difference in DR? Apparently the level at which "noise of the system and the error in digitizing" is not objective.

And it's not just the MSB getting set that matters. That happens at 2^13 in a 14-bit value (hex 10000000000000). That's almost a full stop before nearly all of the bits below the MSB are also set at 2^14-1 (hex 11111111111111). But most 14-bit sensors are lucky if they get to hex 11110000011111 which is about 2^13.95.

rehess Loc: South Bend, Indiana, USA

Ysarex wrote:

For example when a digital camera applies an ISO change while converting the raw data to a JPEG and doesn't effect the ISO change by amplifying the sensor signal. How is that gain?

Does your software talk in terms of ISO?

Mine talks in terms of ‘changing exposure’.

anotherview Loc: California

I've understood that gain in electronics refers to an increase in signal strength -- simplfied defintion. For more, see this discussion.

https://en.wikipedia.org/wiki/Gain_(electronics)

TriX wrote:

Dynamic range in photography describes the ratio, in stops, between the maximum and minimum measurable, recordable or displayable light intensities. In terms of digital cameras, it is bounded on the upper end (max intensity) when the most significant bit (MSB) of the A/D converter (digitizer) is set, and on the lower end (minimum intensity) by the noise of the system and the error in digitizing (and of course, the resolution of the digitizer)

selmslie Loc: Fernandina Beach, FL, USA

Ysarex wrote:

For example when a digital camera applies an ISO change while converting the raw data to a JPEG and doesn't effect the ISO change by amplifying the sensor signal. How is that gain?

ISO is applied in the A/D converter when creating the raw data from the sensor signal.

Many camera presets might affect how that raw data gets used to create the camera’s JPEG but that’s not an ISO change.