I have of late been working with ISO it is my goal to learn the practical way to use it to my advantage. I Have long thought of 1200 as being a high high ISO, make no mistake I still do. It is not the highest I have used, 1620 occupies that position. The background noise at those levels with my camera are not close to what my goal is. I am embarking on merely comparing various settings, to see where it leads me.
The image in the photo was shot at ISO 1200, it is a clear sharp image. However the background noise had to be repaired which is easily accomplished in the photo editor “Lightroom”. Background noise appears as if static has invaded the picture. Much like an itch that can’t be scratched, it will be an irritant unless removed. The details in this picture are merely just OK.
This was shot set to ISO 1000, it is not any better than 1200, in this image the background noise is noticeable. I cleaned up a bit of it, but at least 1/2 of it remains in the picture. Again the details are lacking.
The above was taken at ISO 800, a bit better however the noise was still very noticeable. Although the image is good after cleaning it up, the detail is not what my goal is.
ISO 620 is relatively better as the noise has been reduced substantially, and the detail is improving. I again had to remove the noise but it wasn’t nearly as bad compared to the the higher settings.
ISO 320 is nearly de-void of background noise, I had no clean up what so ever. I could have stopped with this setting of 320 but most cameras are designed to operate of an ISO of either 100 or 200. Details are substantially better, and close to my goals.
I reset the camera to ISO 200, not only has the noise been relieved but the image has wonderful detail. There is not such thing as a one size fits all setting. Because it has to work well with shutter speed and aperture opening; the conditions dictate where it should be set. That takes an enormous amount of experience to know as a seventh sense which setting to use.
I use the AV mode, aperture priority which allows the camera to set the shutter, I still control the f-stop and the ISO. The ISO setting determines how much and fast light is taken in by the sensor. A large aperture opening (low number) allows a bunch of light in, a high ISO dictates how fast and how much light to gather the higher the ISO the more it absorbs. When they are both set the camera tells the shutter how fast to open/close for the best results. I use auto focus employing the various focus modes as needed which depends upon 100% experience for which to use.
Jacques Lebec Flutter Shutter