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Canon 70D ISO Invariance Test 100-6400, Geoff Scott

Canon 70D ISO Invariance Test 100-6400

Canon 70D ISO Invariance Test 100-6400, Geoff Scott

Canon 70D ISO Invariance Test 100-6400

Description

ISO Invariance Test described at http://www.lonelyspeck.com/how-to-find-the-best-iso-for-astrophotography-dynamic-range-and-noise/

The exposures are matched in brightnesses in Adobe Lightroom as follows:

ISO 100 gets pushed +5EV

ISO 200 gets pushed +4EV

ISO 400 gets pushed +3EV

ISO 800 gets pushed +2EV

ISO 1600 gets pushed +1EV

ISO 3200 has no adjustments made

ISO 6400 gets pulled -1EV

It is clear that the Canon EOS 70D is not completely ISO-invariant. It appears that the camera reaches its best low-light performance at ISO 800 and higher. ISO 800, 1600, 3200 and 6400 look almost identical meaning that the 700D might be ISO-invariant from ISO 800 upwards. Below ISO 800 the image quality degrades until the point of being nearly unusable at ISO 100. In order to preserve some dynamic range, but still get the best low-light performance on the 70D, it’s clear from the results of the test that ISO 800 is the optimal setting.

Canon 50mm f/1.8 EF Lens on Baader BCF modified Canon 70D DSLR field ~17 x 25 degrees, Ambient 14C. SkyWatcher Star Adenturer EQ mount, unguided on sidereal rate.

Comments

Histogram

Canon 70D ISO Invariance Test 100-6400, Geoff Scott