Canon 6D 20-megapixel digital camera, Sigma 35 mm f/1.4 DG HSM lens at f/1.4. Forty two exposures at ISO 1600 and 6400 were made for the mosaic. On the sky, the camera tracked the stars using an
Astrotrac, with 29 exposures, 30 seconds each, ISO 1600, then 13 images with 60 second exposures of
the land were made with no tracking, with ISO 6400 and 1600. The land includes multiple focus points
to allow focus stacking for improved depth of field, making a sharp foreground as well as sharp sky.
Final image is 13,196 pixels wide by 9,813 pixels tall covering an angular area of about 138 x 103
degrees. The image here is a crop off the top to give a 1.5:1 aspect ratio. Note, there is no change
in sensitivity with ISO, so the ISO 1600 exposures had the same light and noise levels because the
exposure time was the same. The signal levels on the land exposures were equalized in the raw
converter. ISO 6400 is the ISO I use for live view manual focusing, but I did some exposures on the
land after focusing. This sped up the the varying focus positions on the land. No dark frame subtraction, and no flat fields were used.
More info at:
http://www.clarkvision.com/galleries/gallery.nightscapes/web/mesa.arch.nightscape.rnc05.02.2014.IMG_1685-1742.g-bin10x10-c1s.html
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