Methods used with Imatest Master and Kodak Photographic Step Tablet
Imatest Master
Software and a Kodak Photographic Step Tablet No. 3 (uncalibrated)
were used to measure dynamic range and normalized luminance noise at
different ISO settings (ISO 200, 800, 3200) following
instructions
from Imatest for dynamic range and noise.
Briefly, the
transmission step tablet with 21 steps of 0.15 density was taped and
masked on a 16 inch wide light box. The tablet was photographed with each
micro four thirds camera across the full length of the sensor using a
Nikkor 50mm f/1.2 AIS lens (mounted with Voigtlander m43 adapter) at
f/2.8. The EOS-40D was used with an EF 50mm f/1.4 lens at f/2.8. The
EOS-5D mark II was used with a 50mm f/2.5 macro lens at f/5.6. The tablet
was exposed just slightly off focus as recommended in aperture priority
setting with spot metering. Raw files were converted to 16 bit tif files
with Lightroom 3 and cropped. The Imatest Master Stepchart module
calculated number of steps detected, dynamic range (stops or EV) and
normalized luminance channel noise (percent value). Three exposures were
processed for each camera at each ISO setting. A mean and standard error
of the mean were calculated for each measurement with SigmaStat software.
Tests were repeated with a Stouffer T4110 step wedge.
Panel
From Imatest Master