Sony A1 Image Quality: ISO Invariance — Which ISO to Use, When a Push is Just Fine, Noise and Hot Pixels

2021-04-08 • SEND FEEDBACK |
Related: digital sensor, fairy dust aka hot/stuck pixels, ISO invariance, noise, raw file processing, Sony, Sony A1, Sony mirrorless

ISO invariance means that a raw file capture at some reference ISO along with a push delivers the same image quality as setting that ISO in the camera.

This page evaluates image quality in terms of noise and hot pixels at native ISO versus pushing a lower-ISO exposure during raw conversion. Equivalent results for the two approaches are termed ISO invariance.

Examples of ISO invariance and ISO variance are shown with the Sony A1, together with guidelines on setting camera ISO for the best results.

• Examples of ISO invariance and variance with the Sony A1.
• Best ISO to use, and why.
• Falsifying the myth of highlight loss at high ISO.

Sony A1 Image Quality: Push vs Higher ISO (ISO Invariance)

Includes images for comparison from ISO 100 to ISO 3200.

f6.3 @ 1/250 sec, ISO 3200; 2021-04-05 18:02:14
Sony A1 + Voigtlander FE APO-Lanthar 50mm f/2 Aspherical @ 75mm equiv (50mm)
RAW: LACA corrected, push 0.1 stops, +10 Clarity, scaled 200% linearly

[low-res image for bot]