ISO Noise: 5D Mk III
A posting in one of the photography forums suggested ISO 160 managed noise better than ISO 100 and that multiples of ISO 160 handled noise better than near values that are higher or lower. Here are the results of a simple test I did to examine that assertion.
After dark, a warm compact fluorescent ceiling fixture near one end of a long room was turned on, and a Canon 5D Mk III was used to photograph a Lowepro camera bag at the far end of the room. The only change between photos was ISO, which affected exposure time since Av mode was used. White balance was adjusted based on the white part of the luggage tag and a small slice was cropped from the same place in each file. The stem of the maple leaf on the luggage tag was used as reference for the crops. The process was repeated using a Rebel T2i
| ISO 200 | ISO 104,200 |
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| Canon 5D Mk III Chart | |
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| Click on the chart to see full sized version with 100% view of crops | |
| Canon Rebel T2i (550D) Chart | |
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| Click on the chart to see full sized version with 100% view of crops |
From this quick test, it appears some ISO values handle detail better than others and that choosing a lower value from a range may not provide the best image. Results from a single test like this may not be indicative of performance of all bodies in all circumstances, but it is food for thought.