DotTune: Video Tutorial for AF tuning without photographs

Started Feb 18, 2013 | Discussions thread
Nephi Contributing Member • Posts: 531
Re: Different ranges when I change ISO

entlassen wrote:

I watched the video and performed the DotTune procedure using a D800 with 50mm f/1.4. The tests were done wide open on a USAF test chart, with the camera 9 ft away from the wall. Wireless remote shutter, sturdy tripod, non-fluorescent lighting, camera parallel to the target.

With ISO at 100, I'm getting a valid range from 6 to 11. My midpoint would be 8.5.
With ISO at 200, I'm getting a valid range from 10 to 15. My midpoint would be 12.5.

I did multiple tests at each ISO value to make sure to get rid of any outliers. All tests were done in the same 1 hour time window with no environmental changes.

Any idea what might be causing me to get such a difference in values just by changing the ISO?

Any insight would be appreciated.

Has anyone else tested this?  Does ISO change the values (it shouldn't!).  Adam, have you tested this variable?

-Brian

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