Negative ISO

[robdavis305]

I have a Nikon D90 and was noticing that below 200 iso it goes into negative numbers. I usually try to keep it on 200-400 but was really curious on what the negative numbers mean. I am aware that when you crank it up enough it goes into positive. Thanks and Happy Thanksgiving !!!!!!!!

 

[Goontz]

It's not that it's negative ISO, just values lower than 200, the lowest being 100. I forget the 2 other values that are between 100 and 200, but you can find them in the manual.

 

[Derrel]

On the D90 Lo - 1 means the camera's gain control is set to a value that is approximately 1 full exposure value below the sensor's baseline ISO setting, which is ISO 200. The values in Nikon's "Lo" and "Hi" setting are part of what is called ISO Expansion. The values are not strictly calibrated, and do not necessarily reflect compliance with ISO standards. The D90's lowest,normal, actual, calibrated ISO-compliant setting is 200.

A lot of cameras offer ISO Expansion; some only on the high end, some on both ends, high and low. On the lower end, there is often a reduction in dynamic range,and often time the highlights will block up a bit earlier than they would if the baseline ISO were used.

 

[DScience]

On the D90 Lo - 1 means the camera's gain control is set to a value that is approximately 1 full exposure value below the sensor's baseline ISO setting, which is ISO 200. The values in Nikon's "Lo" and "Hi" setting are part of what is called ISO Expansion. The values are not strictly calibrated, and do not necessarily reflect compliance with ISO standards. The D90's lowest,normal, actual, calibrated ISO-compliant setting is 200.

A lot of cameras offer ISO Expansion; some only on the high end, some on both ends, high and low. On the lower end, there is often a reduction in dynamic range,and often time the highlights will block up a bit earlier than they would if the baseline ISO were used.

OH SNAP!!

Dang it, i've been shooting in ISO LO (ISO 100) forever! Should I keep it at 200?

 

[musicaleCA]

On the D90 Lo - 1 means the camera's gain control is set to a value that is approximately 1 full exposure value below the sensor's baseline ISO setting, which is ISO 200. The values in Nikon's "Lo" and "Hi" setting are part of what is called ISO Expansion. The values are not strictly calibrated, and do not necessarily reflect compliance with ISO standards. The D90's lowest,normal, actual, calibrated ISO-compliant setting is 200.

A lot of cameras offer ISO Expansion; some only on the high end, some on both ends, high and low. On the lower end, there is often a reduction in dynamic range,and often time the highlights will block up a bit earlier than they would if the baseline ISO were used.

OH SNAP!!

Dang it, i've been shooting in ISO LO (ISO 100) forever! Should I keep it at 200?

If you want the dynamic range back, yes.