Shooting a Sony a6400 indoors at 7 pm, 1/125s at f/2.8, I feel like noise takes a noticeable step when I push from ISO 3200 to 6400 — more mush than grain in the shadows. Does anyone have real benchmarks or 12x18 print comparisons that show whether that one-stop jump is clearly visible or just pixel-peeping?
But , on the a6400 at 7 pm, that “more mush than grain” jump is usually the camera’s high-ISO JPEG NR — at equal exposure, RAW 3200 vs 6400 is barely noticeable at 12×18. Turn NR off and shoot RAW (or use LR Denoise) and sanity-check against the a6400 in the DPReview studio scene at 3200/6400: https://www.dpreview.com/reviews/image-comparison; are you shooting JPEG?
Quick test: shoot one RAW at ISO 3200 and one at 6400 with the same shutter/aperture, then push the 3200 file +1 EV in post — on the a6400 (near ISO‑invariant) they should look almost identical, and the pushed 3200 often preserves more fine detail than the 6400 NR “mush” (see Photographic Dynamic Range versus ISO Setting). @quick.orbit58 is right about JPEG NR; if you must shoot JPEG, set High ISO NR to Low. Want to try a 12×18 from the pushed 3200 and report back?