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ISO mode on DSLRs

PhotoMoose

New Member
Joined
Dec 3, 2007
Messages
11
This might be a silly question but how does the typical DSLR sensor implement different ISO speeds? Does the sensor actually somehow change sensitivity or is it a simple matter of multiplying the sensor's recorded input values by the ratio of the current ISO speed to the base ISO speed (e.g. 4x when using 4'' on a camera that supports 1'' at its slowest)?
 

Brad Snyder

Senior Member
Joined
Nov 20, 2007
Messages
6,293
Location
Port Deposit, Maryland USA
Lightroom Experience
Intermediate
Eric, start with the Wikipedia article here:

http://en.wikipedia.org/wiki/Film_speed

and then Google "Digital ISO".

There's some very technical stuff, some out of date stuff, some simplistic stuff. Fundamentally, I believe the answer is yes, increasing Digital ISO is an electronic/mathematical manipulation of the photon count the sensor saw.
 
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