how does ISO work?

[Flats]

Is low noise on high iso a software thing, or a hardware thing?
Is it purely algorithms, or is it related to the sensor, or is it both?

The reason I ask is that I was casually wondering if you could, theoretically, upgrade an older DSLR with better high iso performance via a software update.

If anyone could enlighten me that would be cool.

Thanks
Jonathan

 

[HoppyUK]

ISO and noise performance is a sensor and processing engine thing. I'm not aware of any way it can be upgraded.

Basically, you need a sensor that can collect as many photons as possible, and an amplifier with the minimum posible noise so it can whack up the signal without messing up the shadows (where the noise to signal ratio is obviously highest).

Both sensors and processors are getting better all the time.

 

[TCR4x4]

I should imagine in a few years, there will be no such thing as noise. Just look at where we are now compared to 8/9 years ago.
You can shoot at ISO 6400 and not worry about it on a D700.

Before long even the most basic DSLR will be able to shoot at ISO's we wouldnt even consider now.

 

[Oggy]

Answer C - both of the above. Hardware wise, the signal to noise ratio of sensors is getting better all the time as are the software noise algorythms.

Whether older cameras will be updated is another matter. After all, what is the incentive for a manufacturer to make stay with your existing camera rather than buying a new one.

Tom - I admire your optimism. I have spent 30 odd years in electronics chasing noise in one form or another.

 

[TCR4x4]

Ok, maybe not "no such thing as noise" but more noise that is less percivible than it is today...

 

[petersmart]

Ok, maybe not "no such thing as noise" but more noise that is less percivible than it is today...

Unless there is a sudden quantum change in sensor design then they will continue as they have done for the last decade - better designs and better software.

Personally I don't rely on the in-camera NR - I much prefer to turn all NR off in the camera (or as much as possible) and use custom designed software such as Neat Image in PP to get rid of noise.

.

 

[SLRUser]

It has been said above, it is all down to the sensor being able to collect photons.

The brighter a scene is, the more photons can land on the sensor in a shorter period of time, and in less light conditions the gain of the sensor has to be turned up which introduces noise.

I think that things will gradually improve in the future to a point, but not at the same rate as it has done up until now.

Think of it this way, PC processors are not much faster than they were 5 years ago however because there are now dual, quad and more cores PCs appear faster though only if the application can benefit from parallel processing.