Does increased ISO caused graininess in digital, if so why?

[Bally]

I understand why this happened with film, but sensors are a whole new tech, how did we recreate the same flaws

Just wonderin'

[nardes]

Good question.

DSLR sensors are electronic devices that capture (register) photons as electrical charges/signals. These charges/signals are very small and require electronic storage and amplification components and circuits to record and process them.

These electronic circuits and components also have “electronic noise” which is an unwanted element, produced by the read/write circuitry on the sensor, rather than the actual signal (real data) from your subject.

Under bright conditions and at normal ISO speeds, the magnitude of the signal overwhelms the noise, so your images look smooth and clean.

As we raise the ISO we not only amplify the signal, but we also amplify the inherent componentry noise, especially when shooting under dark conditions when there is appreciably less real signal, so the noise forms a greater part of the image.

Noise also increases with temperature (thermal noise) and conversely, decreases by a factor of x2 with every 6 deg C drop in temperature, so a cooled DSLR will produce less noise.

However, my 5D Mk III DSLR at ISO 1600 produces far cleaner photos than my old Pentax 35mm SLR using ISO 400 film (large grains), where the film grain was relatively large compared to ISO 100 film (small grains).

Cheers

Dennis

[Bally]

Thank you Sir, articulate and clear

Cheers

[Mark L]

... , how did we recreate the same flaws

Just wonderin'

http://www.dxo.com/us/photography/photo-software/dxo-filmpack
Is that what you where asking?

[ameerat42]

I understand why this happened with film, but sensors are a whole new tech, how did we recreate the same flaws

Just wonderin'

Wonder away! Beware of "begged questions" (as highlighted in your original post).
Hopefully the reply by Nardes will have helped scotch the perceived ill by exploding it,
instead of it generating a heap of fuzzy replies..

Wonderful technology, when you change your perspective (as indicated in your second post).