Re: ISO Test Images

"I am not a photgrapher ..."

Neither am I, but I've been in the industry for a long time first on the processing side and these days in software, and I'll try to explain.

ISO is a measure of light sensitivity. In the film days you basically achieved higher sensitivity (ie ISO) by using larger grains of silver halide, hence the grainy appearance of high ISO films (this is an oversimplification, but will suffice). In digital you increase the sensitivity by turning up the gain on the photosites (again a simplification) which introduces noise into the image. You can compensate for this with noise reduction, but this tends to introduce "smearing" so has to be applied carefully. The advantage of a larger sensor is that you can have larger photosites for any given pixel count, which means greater sensitivity, which in turn means you will get better results at any given ISO setting than a smaller sensor.

"For a static target wouldn't it be better to keep the exposure time the same (0.1 - 0.05 seconds?) whilst increasing the ISO. The images would then display an improvement in quality rather than a reduction!"

Doing this would simply result in grossly overexposed images - think about it: you turn up the sensitivity of the sensor by, say, a factor of 4 from ISO 100 to 800. If you keep the exposure time the same then the sensor records an image that is 4 stops overexposed.

The bottom line is that a high ISO image will always be less good than a low ISO image in decent lighting. A large sensor will have better high ISO performance than a small sensor (all other things being equal), and will generally be better in low light but to get a properly exposed image you can't just "turn up the ISO" and leave everything else the same, and expect magical low light performance.

This being the Reg I'm sure someone will be along at some point to tell me I'm wrong about everything in an amusingly cynical way, but I think i've got the basics right...

Re: Re: Included software

"The Sony camera group is producing excellent, innovative products."

Have you used a HX9V? The pictures look great until you zoom in and you see the awful washy watercolour effect from compression/noise reduction. Awesome video capture though :/ It has put me off buying another Sony camera for quite some time.