All digital camera photos contain something called EXIF.
It is data that is obtained from the camera for every picture taken.
The EXIF is embedded in the photo itself.
In my reply, I mentioned a free software program called Irfanview.
If you use that program and load a photo, you can see the EXIF information.
Just Click Image/Information/EXIF info Button.
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ISO is a setting that doubles the amount of light the sensor puts out, each time you double the ISO setting.
i.e. 100, 200, 400, 800, 1600, 3200
But it comes with a penalty.
It increases the noise as you increase the setting.
Most small cameras produce unacceptable noise at about 400.
Large DSLR cameras can go as high as 1600 with almost no noticeable noise.
With a small camera, it is best to leave it at 100.
In Auto mode the camera will raise the ISO setting whenever it needs more light.
So, to keep a certain ISO setting you have to get out of Auto mode.
But if the camera can not raise the ISO setting it will have to lower the shutter speed instead.
So, in low light you could be shooting with a very slow shutter speed.
Something like 1/2 second.
You can not successfully hand hold a camera at that slow shutter speed.
You will get blurred photos due to camera shake (movement).
You should use the flash in low light.
That prevents all the problems mentioned above.
With flash set, the shutter speed will be set to 1/60th or 1/30th of a second (depending upon the camera model).
The flash will illuminate anything within 12 feed (on most small cameras).
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