My Canon Powershot A495 displays a black screen with the white text "BUSY" after taking a photo when the ISO values are cranked up.
The time this screen is displayed varies from zero when the ISO is set to 80, up to about two seconds when the ISO is set to the max value of 1600. Why would this be? Is there some sort of post processing involved with higher ISO values? Is this just a quirk with the A495, or is it common with all the Canon point-and-shoot cameras? Anyone else noticed this?
Canon A495 ISO Overhead
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Re: Canon A495 ISO Overhead
Yep.
Your sensor has a "base" ISO which is probably 80. Each doubling of ISO is a doubling of sensitivity. You can think of it like a guitar amplifier. As you turn the knob up, the signal gets louder but so does the noise.
When you turn the ISO up, they turn up the noise reduction and use more computationally intensive algorithms to get rid of the noise. So the whole process takes longer.
Your sensor has a "base" ISO which is probably 80. Each doubling of ISO is a doubling of sensitivity. You can think of it like a guitar amplifier. As you turn the knob up, the signal gets louder but so does the noise.
When you turn the ISO up, they turn up the noise reduction and use more computationally intensive algorithms to get rid of the noise. So the whole process takes longer.