Downrez...

[Landon D Parks]

I have a question, with this camera I have noticed one thing that seems to bother me. Unless you shoot and record in 4k mode, your not getting all of what its possible to get. It says that shooting in 2k will window the sensor, effectively reducing the image size down to that as if it was shot with a 2k sensor... You loose 1/2 the resolution of the sensor as well as the shallow DOF.

Is there some way that you can record the image in 4k (35mm size) or even 4.5k (S35mm Size) and then down-convert that image to a 2k file BEFORE recording to the Red drive?

I'm not a video expert, so I'm not sure what this down-sampling would do to the image quality, but it seems to me that even if you don't plan to use the full 4k footage, you should still be able to get the same sensor size and original pixel count as if you shot in 4k...

Maybe it is possible to down sample in Red cine after recording as well, which would work I guess.... I just cannot edit and/or use 4k footage at this time.

PS) I was reading though that it is possible to record in 4k, bring it into Red cine and then edit in a lower format then export an EDL to red cine and it will conform the 4k to the edit.... That sounds nice and all... however: Your going to have to have a system capable of 4k color correction as well as 4k finishing, which doesn't help me much at all. :bye2:

 

[Dominic Jones]

Hi Landon - welcome to Reduser mate!

There is talk of a 2k scaled recording option, which would address the issue of DoF for you, although of course resolution would still take a big hit (fyi, when you move to 2k you lose 3/4 of your resolution, not 1/2, as 2k is 1/4 the resolution of 4k (half res in both axes).

2k is still looking pretty fine though, and is definitely useable, even for theatrical work - a lot of major pictures are DI'd at 2k presently, for instance.

Covering the point made in your PS, no you don't necessarily need 4k conform and CC tools for this route - you can quite happily edit offline at, say, 720p and then conform to 2k via RedCine (keeping the full image but simply downrezzing to 2k) for your final master (Apple Color will happily handle that, for instance) and then keep your 4k master files in case you ever want or need to do a 4k conform/filmout in the future. It's a very good workflow which future-proofs your project.

Also, AE can happily conform at 4k right now (from a DPX sequence, for instance), which would be a clunky way of doing it, but still totally plausible for low-budget indie stuff. I guess the point I'm trying to make is that there are plenty of solutions out there, the only question is picking the correct one for you...

Hope that helps, and enjoy the forum - any questions you have, search around as most topics already have about 3 million conversations pertaining to them, there's a lot of friendly informative folk around here!

 

[dvpixl]

Does it window at 1080 and 720 as well or would it just downrez? Will 35mm lens work on a windowed 1080 or 720?

 

[Chris Kenny]

I have a question, with this camera I have noticed one thing that seems to bother me. Unless you shoot and record in 4k mode, your not getting all of what its possible to get. It says that shooting in 2k will window the sensor, effectively reducing the image size down to that as if it was shot with a 2k sensor... You loose 1/2 the resolution of the sensor as well as the shallow DOF.

Is there some way that you can record the image in 4k (35mm size) or even 4.5k (S35mm Size) and then down-convert that image to a 2k file BEFORE recording to the Red drive?

There's no point. In order to scale to 2K, you first have to turn the RAW data into RGB data. RGB data is harder to compress, so 2K RGB would likely take up just as much space on your capture medium as 4K RAW. The 4K RAW has more resolution, and gives you more flexibility in post, so you're better off just recording that. The quality of down-conversion possible on a desktop system is almost certainly higher than what would be possible to do in real-time on the camera anyway.

Thanks to the tricks that wavelet compression makes possible, you can extract fractional resolutions like 2K from the 4K RAW file without having to decode the full 4K anyway.

 

[Ed Wes]

Ever since I read about 2k scaled down there has a pesky thought has been popping up and does not seem to want to go away. I am not an engineer and as the idea does not seem to want to go away I thought I should share with those who might be in a better position to evaluate the proposition. I am wondering what strategy will be used to scale down 4k to 2k. One could simple throw away 3/4 of the chip's information, as is being done with the windowed 2k, or one could average out the information from the four pixels. This second strategy I imagine would reduce noise and effectively increase dynamic range. In effect one would be quadrupling the size of each pixel. Theoretically, if I am not mistaken, one one could increase the dynamic range by two stops. With the right software algorithm one could shoot in 4k and do the the conversion in post, or perhaps it could be done in camera.

Have any of the engineers had any similar deviant thoughts. I imagine that one could workout a more sophisticated algorithm than a simple average, in which any radically deviant pixel is simply dropped from the average. This might further decrease noise.

 

[Ed Wes]

The obvious corollary, if my reasoning is right, is the possibility of a two stop speed increase at 2k. Better than a poke in the eye with a dead fish.