That would probably be a lot less than 2%

I can only refer to what I know is in my Nikon menu system but Think about all the slideshow functions, the creative settings like processing images on-camera, black and white conversion or sepia that kind of thing.

Battery discharge
Switch between pict-bridge,usb and PC Sync.
I can think of a few things that I setup when I first configured the camera and haven’t touched since like folder names or function button settings.

It’s a bit like a mobile phone. It makes calls and you send SMS/MMS on it. All the other stuff is great but most people hardly ever touch those features.

I have also wondered about this.

I hope that part of this series of posts will make for better decisions on the type of venues you are shooting in, which will be covered more later.
As we all appreciate the key thing in photography is light. In a venue where you are not allowed to use flash, the chances are the lighting system is immense.

A real world example: If you are shooting at Wembley Arena, you can quite comfortably use ISO 400/800 to get a clean exposure without using flash. The only reason I can see for needing to increase that is if for some reason you were having to use a 400+ zoom lens and you are losing 2+ stops on the zoom.

Digital ISO is the one thing which has always bugged me and it is great to see such a debate already starting on its merits. I think for me it is all because of the desire to compare the mechanical performance of the chip in the same way as the chemicals reaction on film is not just.

As better sensors are produced do they create better images? Yes they do, they also produce them better at higher sensitivity ratings. My point is ISO 1600 film is ISO 1600 film, there are slight difference between manufacturers but a spade is a spade if you like. With a digital sensor you cannot compare it in such a way.

Another real world example: look at image comparisons on dpreview.co.uk between any two cameras. The differences can be vast. It is not the same as loading two different cameras with the same ISO rated film and then comparing the end results.

Thank you for your post. It is harder than I thought to explain how it works without going into excessive detail.

The link found by clicking on noise to a wikipedia page does go further into detail on how digital noise occurs which is a common side affect of digital ISO.

There is also a very in-depth explanation on Film Speed and signal-to-noise-ratio relating to Digital ISO here http://en.wikipedia.org/wiki/Exposure_index.

To follow on from my original post, before the processor is provided with the image information it defines how sensitive to light the image sensor should be. Higher ISO means more sensitive sensor.

However this sensitivity can cause digital noise, which takes many different forms.

I highly recommend the link which I have just added to the further reading section for more on exposure in digital photography.

Please do keep commenting and on future posts. I greatly appreciate and value all your contributions.