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redeeman 10 days ago

also, you can do 120fps on your Z8, but it reduces to 11MP, this goes for both Z8 and Z9. It also uses video mode for this, but goes to show sensor readout is not the issue :)

tristor 10 days ago | parent [-]

The reason it requires reduction to 11MP and to use the video pipeline instead of the Expeed pipeline is due to sensor readout time. I don't /fully/ understand it, but the sensor readout data on the Rolling Shutter Project shows a Nikon Z8 would max out at ~22fps in full-frame RAW, so no doubt they reduced this to 20fps to give them a margin of error. Reducing to the DX frame size reduces the amount of data required to be read from the sensor, which changes the time it takes to do a readout. The Z8/Z9 are 45MP cameras, so just doing a naive bit of maths, you could expect ~80fps if you applied the same pipeline at the DX frame size, but given that there is already a video pipeline and they needed it to be capable of 120FPS, they already had their answer.

redeeman 10 days ago | parent [-]

both video and photo pipeline is expeed. it does not go into DX mode for 11MP, its full sensor size. its unclear(atleast to me) if it does some form of line skipping or if its oversampled fully.

but the video mode supports full 8k60 atleast, so only a very tiny crop.

tristor 10 days ago | parent [-]

It's definitely not straightforward, there was no 8k originally AFAIK, that came through a firmware update and as far as I know is a totally different format that makes use of ticoRAW as a base (https://www.dpreview.com/news/9624409613/nikon-is-licensing-...), so RAW video isn't recorded in the same format as RAW photos (N-RAW vs NEF).

It can only do 8k60 though, not 8k120, so obviously the video pipeline and the C120 pipeline aren't identical.

When you say it doesn't go into DX mode for 11MP, you're correct for C120, but for C60 it /does/ go into DX mode (which captures a 19MP image). How this differs between C60 and C120, I'm not entirely sure in the camera internals. I had thought the resolution reduction is from cropping, but confirmed in the manual that when you enable C120, it's an 11MP photo but is full frame (no cropping).

Obviously this stuff is complex (maybe overly complex) and I haven't delved into it super deeply since I don't need it for my type of photography (and I never do video).

redeeman 9 days ago | parent [-]

it did initially offer 8k60 in the ticoraw.

but this suggests that the limitations are not in sensor readout, but processing/saving. Its speculated that its due to heat problems if doing faster than 20fps full raw