RED's CMOS Sensor Rolling Shutter or Global Shutter?

[Neil B Smith]

Can anyone from RED tell me if the RED sensors on the Scarlets use a "Rolling Shutter" or "Global" shutter?

I've read most digital cameras currently on the market that use a CMOS sensor use a Rolling Shutter.

 

[Jerrod Cordell]

It uses a rolling shutter, but its a lot faster than the 5D or the D90 for example. The skew is basically virtually non-existent.

 

[Dan Hudgins]

Dwell time

Dwell time

Because the senors can go 120fps or so, they can use about a 5:1 dwell:readout ratio that is close to what some movie camera shutters have.

They also have a "open gate" mode that runs the sensor at 48fps for shooting 24fps.

I would expect that the dwell to readout ratio goes down at higher fps, but I have not seen a clear answer to that. The same may be true for the copression ratio, if they store more frames per minute with the same bit rate, someting has to give?

 

[Neil B Smith]

It uses a rolling shutter, but its a lot faster than the 5D or the D90 for example. The skew is basically virtually non-existent.

Many thanks...

I've seen some footage from the Canon and the skew looks bad on fast movement. I understand that some developers of CMOS sensors are now developing sensors with Global shutter which gets rid of the rolling shutter artifacts. RED has spent a lot of time on their next-generation sensor so it would be good to hopefully see some various footage from the Scarlet & Epic and see how it compares to the RED One.

I personally wouldn't buy the 5D because my line of work is corporate video production. I can see that a 5D is ok for a stills photographer but not for professional video operator.

The RED One is an excellent camera, but kitted out it weighs a tonne! I mainly have been using the XDCAM HD range of cameras and the RED One was more than double the weight of those cameras. I'm hoping the Scarlet is more up my street for a "near-to-film" quality non-tape based camera that I can use on the move. All day. :driving:

P.S. Many thanks for the other replies to my questions. Very helpful !!

 

[Steve White]

Not an expert by any means, but Jannard had several posts talking about how the read/reset time on Mysterium-X was down significantly from the original Mysterium. This means even less skew for the next round.

If you're looking for skew in Red footage, consider District 9. It was shot on Red, with a lot of fast action, effects work, and moving shots. I never noticed skew being a distraction, and quite obviously the VFX crew handled things.

 

[conrad gaunt]

It uses a rolling shutter, but its a lot faster than the 5D or the D90 for example. The skew is basically virtually non-existent.

You need to pan around with a little too much speed, a long lense, and probably with a fast shutter speed, but you can induce "extreme jello effect", I saw this at 120fps while messing about.. but practically speaking its not an issue for normal usage shots.

 

[rayoncena]

Red sensor uses rolling shutter but the problem with that is it need long read reset time and even when you use strobe lights, scenes with flashes goes off. And id you go with global shutter for narrative film making in an open environment there is a big problem of cmos chip.

 

[Kemalettin Sert]

watched this test

and cameras with global shutter looks best compareble to 35mm..
Weisscam,F35 and Flex beat the other cameras..
so why Red uses rolling shutter?? is there any specific and sensible answer for this besides it looks like dslr-ish..

 

[David Rasberry]

Motion film cameras have rolling shutter issues too. If one follows the camera motion guidelines set forth in the ASC manual fot things like panning speed, it is not much of an issue with Red cameras.

 

[Sanjin Jukic]

Jim told us before that they are not looking to employ any mechanical shutter that can resolve rolling shutter artifacts as Sony F65 or Alexa Studio already showed.

But what they going to do?

Probably with the next Epic sensor upgrade a.k.a. RED Dragon they will go CMOS with global shutter.

Read more about a CMOS global shutter implementation at Viimagic page >>>

Also could be that Scarlet will get similar CMOS sensor solution that would be gorgeous just because it's lightweight, ideal camera for a handheld and fast panning around.

But still it remains unknown till Nov 3rd if they go S35mm sensor size @ 1080p/2K or with some of older concepts as a 2/3" 3K sensor size...

 

[Steve Wake]

Everything about HDRx tells me it relies on reading each line twice before moving to the next line, i.e. it relies on rolling shutter. RED's strong comments about continuous lighting being the future of DSMC could indicate they don't plan to change the rolling shutter. A global shutter should work fine with strobes, even short duration speedlights. On the other hand, maybe Dragon or Monstro's DR will render HDRx obsolete, or RED will implement a completely different version of HDRx that works with a global shutter.

 

[Dave Blackham]

I not so sure that Global shutter is any better, rolling shutter is fine if its implemented with short switching time. Im more interested in the slow on to off exposure of the sensor, so motion artefacts are improved (there is a product advertised on this board but cant remember what its called that offers this functionality.)

 

[Sanjin Jukic]

"CMOS Image sensors with global shutter and high dynamic range" is only way to go.

Read more >>>

 

[Terry VerHaar]

AFAIK, right now global shutters are somewhat impractical for CMOS sensors and CCD sensors have limitations that have caused the industry to adopt CMOS for motion capture applications, such as RED has. One could argue that global shutters are also not "film-like" in their look because film does effectively have a "read-reset" time much like a CMOS sensor. (That is, of course, a subjective argument about the "look"). The effective read-reset time of a film camera is about 4 ms while the Epic has gotten the read-reset time of its sensor down below 8 ms (or less, I believe; could be as low as 5?). This makes rolling shutter artifacts in RED cameras nearly negligible. Maybe global shutter CMOS will eventually win the day but many things can happen before that time, including an argument about its desirability. Heck, maybe 60fps will be the standard by then. :laugh: