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Pentax K3

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K3 Raw Maze Pattern Noise

Converted from raw DNG into a 16-bit ProPhotoRGB TIF file using Adobe Camera Raw.

Something peculiar exists in this image: a subtle crosshatch pattern exists throughout the image.

I first noticed it in the even-tone areas in the waterfall area, but the effect exists everywhere in the the frame whether the area is light or dark; detail confuses the issue, and it tends not to be seen in high-key smooth areas. JPEG is not involved at all except for presentation purposes here, and the JPEGs as shown here matches the 16-bit TIF.

Since Pentax specifies a 14-bit sensor/file (Color depth: 8 bits/channel JPG, 14 bits/channel RAW), the file size of 31.9MB makes it plain that some form of compression is being used (24MP at 14 bits uncompressed implies a 42MB file size). If lossy compression is being used, that might be the culprit. If lossless compression, then that implicates hardware.

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Diglloyd DAP is DSLR-oriented, but also contains workflow and other topics. Much of the focus is on Canon and Nikon but also Pentax and Pentax medium format.

Special emphasis is placed on lens evaluation, focusing on Canon and Nikon and Sigma lenses, but with a few others like Rokinon/Samyang.

  • Make better images by learning how to get the best results right away.
  • Save money by choosing the right lens for your needs the first time, particularly some of the new Sigma Art lenses vs Nikon and Canon.
  • Workflow discusses image organization, raw conversion and post processing. Many examples show processing parameters for direct insight into how the image was converted.
  • Jaw-dropping image quality found nowhere else utilizing Retina-grade images up to full camera resolution, plus large crops [past 2 years or so].
  • Real world examples with insights found nowhere else. Make sharper images just by understanding lens behavior you won’t read about elsewhere.
  • Aperture series from wide open through stopped down, showing the full range of lens performance and bokeh.
  • Optical quality analysis of field curvature, focus shift, sharpness, flare, distortion, and performance in the field.

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f/2.8 @ 1/1250 sec, ISO 100
Pentax K3 + Pentax 40mm f/2.8 @ f/2.8

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