EOS 90D Black Level

[Marc Hildebrant]

Group,

My assumption is that the Black Level set in the EXIF File is based on the ISO setting, rather than a measured value from the Masked Pixels. Is my assumption correct?

Marc

 

[smoke665]

Group,

My assumption is that the Black Level set in the EXIF File is based on the ISO setting, rather than a measured value from the Masked Pixels. Is my assumption correct?

Marc

The black level tag is the digital offset value the camera uses to reference pure black. It ensures that even when no light hits the sensor the output wont be zero.

 

[Marc Hildebrant]

smoke665,

I noticed that this value changes with different ISO settings.

Marc

 

[smoke665]

smoke665,

I noticed that this value changes with different ISO settings.

Marc

Because ISO in digital is "gain" (amplifcation of the digital signal). Gain makes the image brighter by increasing signal strength across board, leading to shifts in shadow detail and true black.

 

[Marc Hildebrant]

smoke665,

Thanks. That makes sense.

Marc

 

[smoke665]

smoke665,

Thanks. That makes sense.

Marc

You should also see a WhitePoint tag that specifies the coordinates for the image white point, ColorSpace tag, and a WhiteBalance tag.

 

[Marc Hildebrant]

EXIF, using Rawdigger on my Canon EOS90D.

I see WhitePoint info, colorspace,and much more. Interesting reading.

Marc