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FS5's 1080p question

Kendrick Gray

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Again, remembering that a raw signal is not something converted to viewable color...


The 4K bayer-sensor raw signal has to be debayered live to RGB (even just to see a color image on the camera's viewfinder) and the camera records that 4K color image to an XAVC format (or with a raw license and and an external raw recorder, apparently you can record 4K raw).


It also downscales that to 1080P in camera for recording (and for viewing, remember the viewfinder isn't 4K after all).


The camera also has a "center scan" mode -- from the Sony site:


Center Scan mode captures the center of the image at Full HD (1920 x 1080) resolution. Not only does this provide an effective 2x zoom with 35mm glass, but it also enables you to mount 16mm PL lenses via third-party adapters.


Meaning that in this mode, a 1920 x 1080 center crop of the sensor is used for the image rather than downscaling the debayered 4K raw signal.


Keep in mind that I don't think any camera downscales in raw, i.e. sends a 4K raw signal from the sensor and downscales (rather than crops) to 2K or 1080P while not converting the image to RGB first, though some cameras will do tricks like pixel binning and line-skipping to get a 4K raw signal down in size.


The Sony site says that the XAVC-Long codec for 4K or 1080P is 10-bit 4:2:2 at 50 Mbps for 1080P.



The camera also can record the AVCHD codec for 1080P, which is only 8-bit 4:2:0 at 25 Mbps.

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Good information. I was wondering if they degraded the image somehow to make it 1080p. I seen some 4k cameras with crappy 1080p. The 1080p on this camera is quite good. Glad thats cleared up. I just have a need to know everything.

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Yes its not degraded.. on the f5/55 you are getting a very good HD image from the over sampling of the 4K to HD.. Sony call it super sampling :)


I haven't used the Fs5 ,but there were problems with its image till a big firmware up grade.. but the UHD being 8 bit (internal) is a big draw back.. IMHO.. having to have an ext recorder is always a pain..


Centre scan is a very useful thing.. I believe the Amira can now do this in the most recent firm ware up grade.. originally Sony only saw this as a means to use S16 lenses.. and you cant assign it on the F5/55.. now they have realized its use as a lossless digital extender (in HD).. I believe its assignable in the Fs5.. and oddly on the C300II.. centre scan is only in slo-mo (as with the Sony,s over a certain frame rate) .. but cant be applied in sync modes! so no digital extender.. why Canon... as if there weren't enough reasons not to buy one !

Edited by Robin R Probyn
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