Pentax K-3 III Samples

The Pentax K-3 III is compared to the Fujifilm X-T4
Fujifilm X-T4, below. Although there are completely different cameras, they are both modern flagship APS-C models designed for professional photographers. They each feature a 26 MP sensor without Anti-Alias Filter but the X-Trans technology in the X-T4 makes in impervious to moire. All images below are 100% unmodified crops from their respective cameras. Both cameras were set on aperture-priority mode with fixed ISO. The remaining settings were left on automatic. Cameras were each independently calibrated to deliver optimal image quality.

These crops help determine which ISO sensitivities are acceptable to used on these cameras. Most cameras compensate with noise reduction as noise increases but this introduces softness. The point at which a print becomes unacceptably noisy is a matter of personal taste.

Pentax K-3 III	Fujifilm X-T4
ISO 100	ISO 100
ISO 200	ISO 200
ISO 400	ISO 400
ISO 800	ISO 800
ISO 1600	ISO 1600
ISO 3200	ISO 3200
ISO 6400	ISO 6400
ISO 12800	ISO 12800
ISO 25600	ISO 25600
ISO 51200	ISO 51200
ISO 102400	These two 26 MP APS-C CMOS sensors exhibit highly similar image-noise. The Fujifilm one shows a minimal advantage at ISO 100 and 200, while noise-levels from ISO 400 to 3200 are identical. Above that, crops just show a different trade-off between detail and noise. The main difference between the output of the Pentax K-3 III and Fujifilm X-T4 is that the latter captures more dynamic-range and keeps more gradation in highlights. Even with Highlight Correction enabled, the Pentax K-3 III cannot hold as much dynamic-range.
ISO 204800
ISO 409600
ISO 819200
ISO 1638400