EPIC Frame Rates

[Casey Green]

RED has stated that EPIC will be able to shoot 5K at up to 100fps. This will give shooters many options while still having the utmost image quality.

As the RED ONE had more modes added to it, so too will the EPIC, one would think. This begs the question:

What will lesser resolution recording modes yield in terms of frame rates? RED ONE can shoot 4K@30fps, 3K@60fps, and 2K@120fps.

If these ratios hold true, what might we see with EPIC at 4K? 3K? 2K?

 

[Matthew Lochman]

RED has stated that EPIC will be able to shoot 5K at up to 100fps. This will give shooters many options while still having the utmost image quality.

As the RED ONE had more modes added to it, so too will the EPIC, one would think. This begs the question:

What will lesser resolution recording modes yield in terms of frame rates? RED ONE can shoot 4K@30fps, 3K@60fps, and 2K@120fps.

If these ratios hold true, what might we see with EPIC at 4K? 3K? 2K?

5k@100fps, 4k@200fps, 3k@400fps, 2k@800fps :w00t:

 

[Brook Willard]

I suppose the limiting factor becomes the sensor's ability to refresh quickly. For example, by this math, the RED ONE should be capable of 480fps in 1K. It is impossible as the maximum refresh rate of the sensor is 120hz.

So ultimately we'll be limited by whatever the max refresh rate of the new sensor is.

 

[Casey Green]

Yes, that will be the case.

Jim, can you shed any light on this subject?

 

[Matthew Lochman]

If you consider a traditional rolling shutter (with a deserved bad reputation) is, for reference, a 40... Boris and Natasha ("Crossing the Line") were about 25 (still plenty of skew). The current RED ONE (original Mysterium) is now about 8-9. Considerably better than any "rolling shutter".

Mysterium is a break-through sensor. But it is no secret that sensors still do not have the DNR of film. It is also no secret that sensors will some day surpass film in every aspect. We have a sensor program in place that will put pressure on every other sensor program AND film. The sensor is the heart of a camera. If we don't lead in this area, we do not deserve to sell cameras. The trick to all this... is to lead in sensor technology (which we plan on doing) and make the upgrades to our cameras as painless as possible. That's what will separate us from all others.

Jim

And then someone asks what the Mysterium X sensor will be set to...

About 5.

The Mysterium X will have more DNR than Mysterium and faster read-reset. Monstro will be set to "3" and have much more DNR still...

Jim

 

[Matthew Lochman]

I'm not sure what the relationship between Read-Reset times on a rolling shutter and the refresh rate of the sensor Brook is referring to.....

 

[Brook Willard]

Yeah, that's different. THe RED ONE's shutter can be set to a 1/2,000th of a second... but that doesn't mean it can shoot 2,000 frames per second.

The refresh rate I'm referring to is the number of times per second that the sensor can "capture" an image. For the RED ONE, the publicized figure has been 120Hz.

 

[Jason Rodriguez]

Hi Brook,

If "120Hz" is the pixel-clock of the ADC on the theoretical sensor (we're not talking about EPIC here, just some theoretical sensor), and at that pixel clock it is capable of 4K at 120fps, then theoretically yes, at 1K you could do 480fps.

This is because you have to combined the pixel-clock with the number of pixels that it reads out a maximum resolution (+blanking). This makes more sense if you divorce the physical resolution of the sensor and just think of it in terms of pixels-per-frame.

For instance, let's say you have 9Mpix per frame+blanking, and this theoretical sensor requires a master ADC pixel clock of 75Mhz to read-out at a full 60fps. That means for every second, you are reading out 540Mpix/s + blanking (note: the reason it's not 60Hz is because horizontal and vertical blanking adds extra virtual "pixels" to the image that are not visible on the screen).

Now, this 9Mpix "frame" could be a 4K wide-aspect ratio frame, it could be a square frame, it could be any aspect ratio you want. But they key here is the 540Mpix/s number . . . that means in a given second, no matter the frame, or aspect ratio, the sensor can read out 540Mpix/s.

So let's say we now only have a 4.5Mpix frame through "windowing" . . . well, I still have at the 75Mhz pixel clock the ability to read-out 540Mpix/s (+ blanking). So now to get that 4.5Mpix frame to generate 540Mpix/s I have to double the frame-rate.

Halve the number of megapixels in the frame again through windowing to something like 2.25Mpix per frame . . . again, you have to double the frame-rate in order to reach the 540Mpix/s frame rate, and now you are also 4x the frame-rate you were originally at when you were at 9Mpix per frame. The pixel clock though is still at 75Mhz all this time though, that part hasn't changed.

Of course, after a certain point where the fps get really high, you also have to watch out for the analog timing on the sensor, meaning what I'm describing above is the digital read-out chain of the sensor controlled by the pixel clock. After a certain point you are reading out frames so fast that the analog portion of the sensor will not be able to achieve the proper "settling" time to fully reset each photodiode or transfer charges optimally, and you'll end up with more noise and other artifacts from poor analog timing.

Thanks,

Jason

 

[Mitch Gross]

Of course, after a certain point where the fps get really high, you also have to watch out for the analog timing on the sensor, meaning what I'm describing above is the digital read-out chain of the sensor controlled by the pixel clock. After a certain point you are reading out frames so fast that the analog portion of the sensor will not be able to achieve the proper "settling" time to fully reset each photodiode or transfer charges optimally, and you'll end up with more noise and other artifacts from poor analog timing.

Yes, and this is no small affair. One can think of this as a form of reciprocity failure for those of us old enough to remember film. ;-)