digital iso question

[StvShoop]

ok... my digital camera has a mechanical shutter, and settings to change the shutterspeed and aperture size...

that makes sense, but why does a digital camera have a range of iso settings? :? isn't iso all about chemical stuff? what changes do different iso settings affect in the making of a photograph in a digital camera?

i know about graininess and exposure, thats not what i'm asking
i understand how to work it, i'm just curious about how it works

 

[Artemis]

I thought ISO was like the type of film...3000 and what not, isnt that its versions of how much light you want to let in?

 

[i like yoda]

As far as I know, it's the same as in film cameras. Only, in a digital camera, the image sensor is just simulating the ISO.

 

[jadin]

ISO is how sensitive your film is to light. In digital it's technically just "light sensitivity" but since most everyone knows it as ISO, they stuck with those initals.

 

[Ant]

It's like turning up the gain on the photosensors, making them more sensitive to light, but also increasing noise in the process.

 

[Big Mike]

Higher ISO allows for faster shutter speeds which allows for better hand held shots.

When it starts getting dark, you can open up the aperture until you get to the lens's max. Then you can slow down the shutter. Pretty soon the shutter is at 1/60, 1/30 or 1/15...now it's would be tough to get sharp, hand held shots. Not to mention if you need to close the aperture for more DOF.

The solution is to bump up the ISO (at the cost of digital noise).

 

[Artemis]

noise?

 

[Youngun]

yeah, noise. Little variously colored dots that are the equivilant of grain in 35mm. However while sometimes grain looks good, noiseis always a bad thing.

 

[StvShoop]

It's like turning up the gain on the photosensors, making them more sensitive to light, but also increasing noise in the process.

GAIN! ok, that makes sense thx

i thought it was some kind of simulation, a kowtow to film, which really had no appropriate place in digital. but yeah, gain makes a lot more sense.

 

[Jeff Canes]

ISO is how sensitive your film is to light. In digital it's technically just "light sensitivity" but since most everyone knows it as ISO, they stuck with those initals.

I agree with Jadin, it just to simulate film sensitivity in a way most people would be familiar with

 

[Digital Matt]

yeah, noise. Little variously colored dots that are the equivilant of grain in 35mm. However while sometimes grain looks good, noiseis always a bad thing.

I don't think noise is always a bad thing. If I convert a shot to B&W sometimes I like a little noise. Sure it doesn't look like film grain, but I think it has it's own charm in certain cases.