ISO 400,000,000 or was it just ISO 6,000,000?

If you increase the ISO enough you end up with a white image. No matter how dark your actual scene was. After brightening my image 16 stops in Lightroom I finally got the totally white image that I expected after just 12 stops of brightening,

 

If you want to brighten more then 4 to 6 stops in lightroom you need to export and reimport a 16 bit tiff. The tiff export produces a darker image than it should. So the real ISO of the photos is a bit less than the calculated one.

 

Since I started with a 12 bit raw file from my Canon 350D I should have ended up with a totally white image with a post processing for ISO 6,553,600. But lightroom screwed up the tiff exports and darkened the image during this step.

 

Canon 10.0-22.0 mm

Canon EOS 350D DIGITAL

22 mm

1/80 Sek.

f4.5

Exposure correction 0

ISO 1600

IMG_1550 ISO 6,553,600-3.jpg

Done