It depends on the film, its aspect ratio, and who is doing the transfer.
I had an opportunity to compare some Marvel movies from their DCP to the Blu-ray. One of the 2.35:1 films was simply cropped from theatrical 2K down to 1920x1080 for the Blu-ray. The Avengers was 1.85:1 on theatrical and the Blu-ray was expanded to 16:9. So the Blu-ray actually had more picture while the theatrical was cropped. I believe on the UHD they cropped it back to 1.85:1 again.
Media: LG 77" OLED 4K C8 / Denon AVR-X8500H 7.1.4 / Oppo UDP-203 / Nvidia SHIELD (2017) / Apple TV 4K / Sony 4K FMP-X10 / Gaming PC (Threadripper 1950X / 2x GeForce GTX 1080 Ti SLI) / PlayStation 4 Pro with PS VR / PlayStation (original) - Family: Sony 85" 4K XBR-85X900F / Denon AVR-X3400H 5.1 / Nvidia SHIELD (2017) / Apple TV 4K / C64 Mini - Game: Hisense 55" 4K 55H8C / Denon AVR-X3400H 5.1 / Nvidia SHIELD (2017) / Apple TV 4K