Mechanical shutter?

[Johnbutler]

The epic would rock if it had one. No more RS artifacts, something that's hampered the red one somewhat since day one.

[chuck colburn]

Mirror reflexing a camera limits the type of lenses you can use on it.

[Stephen Williams]

Mirror reflexing a camera limits the type of lenses you can use on it.

Hi Chuck,

It never hampered Fries Engineering much, I have Nikon, Panavision & Pv mounts for my 35R3.

Stephen

[chuck colburn]

Hi Chuck,

It never hampered Fries Engineering much, I have Nikon, Panavision & Pv mounts for my 35R3.

Stephen

True enough my friend. But you can't use Leica M mount and many non retrofocus wide angles out there. Like that superb Canon 19mm. But all in all your right there are plenty of good lenses to choose from even with a spinning mirror or beam splitter type reflex viewing system.

[DanWood]

This is from another thread:
Sony has developed a 35mm CMOS 24x36mm 24.81 megapixel imaging sensor.
It output all pixels at 6.3 fps with lower noise. This is achieved by “Column-Parallel A/D Conversion Technique” whereby each column of photosites is given its own Analogue to Digital Converter.

So far this is the best CMOS chip in this segment. It will be used in SLR cameras. If this chip is used without a shutter in a videocamera, the RS problem will be reduced but not eliminated.

Sony and Panasonic have half a century of R&D and they use CCDs for a reason.
Origin and ARRI have quietly spent years researching this stuff before using a shutter solution.
This is one of the resons for their higher price tag.

When a shutter solution is used, the price of the camera will be higher than $17K.
For $17K, you have to accept some compromises.
You may never get such a low price from Sony or Pani or anyone else. Because they all sell through middlemen.
Sony executive told me that the Sony factory gets only 25% or less of the suggested retail price.
The rest is all eaten up by middlemen.
So, to sell for $17K, sony has to produce it for $4.25K or less.

'no overhead' is the reason why Jim can give you a camera this cheap.
In the future, I hope, Jim might produce a more expensive camera with a shutter solution.

[Deanan]

Mirror reflexing a camera limits the type of lenses you can use on it.

Mirror reflexing limits how far away you can put the OLPF which affects dust visibility and other issues.

[chuck colburn]

Mirror reflexing limits how far away you can put the OLPF which affects dust visibility and other issues.

Oh yeah... forgot all about that filter back there.

[Dan Hudgins]

Mirror reflexing limits how far away you can put the OLPF which affects dust visibility and other issues.

You can put a flat shutter in like an eyemo to get rid of the rolling shutter and use global release, it does not need to be a 45 degree shutter. You could also have a slide in PLZT or LC shutter to have an option for rolling or global shutter.

[Davide B.]

Even with a mechanical shutter couldn't you still get rolling shutter issues? I mean the CMOS still has to scan the image either way, and if it's not doing it fast enough you're going to get artifacts. The DALSA has a mechanical shutter but it also uses a CCD with a global electronic shutter to keep from getting rolling shutter artifacts.

[Dan Hudgins]

Even with a mechanical shutter couldn't you still get rolling shutter issues? I mean the CMOS still has to scan the image either way, and if it's not doing it fast enough you're going to get artifacts. The DALSA has a mechanical shutter but it also uses a CCD with a global electronic shutter to keep from getting rolling shutter artifacts.

With the Global shutter you set all pixels to gather charge then open the mechanical shutter, hold open for a while, then close the mechanical shutter, then start the "rolling" readout. Since the mechanical shuter is closed during the readout there is no visable rolling shutter artifact.

The artifact from the mechanical shutter depends on its radius just like in a movie camera like the Mitchell NC has a larger radius than an Eyemo. You can use two counter rotating shutters to get a faster open and close time.

[Justin Anderson]

A mechanical shutter would greatly push up the camera price. It would also require additional maintainance and hardware support from the RED team, which would also push up the price.
All of this work and price increase to appeal to a very small portion of the market who needs a global shutter in a camera. If I have a scene in a movie that requires filming strobe lights or machine guns or whatever, I'll just rent another camera for those shots or find some workaround with the RED.

[Jeff Kilgroe]

The rolling shutter or CMOS scanning skew would not be fixed by a mechanical shutter -- only if the sensor itself were made to be a "global shutter". Mechanical shutter would add significantly to the cost and would become an issue with OLPF placement. ...OK, I guess I'm just summarizing all the cons of a mechanical shutter.

Pros of a mechanical shutter? Well, assuming the upcoming Mysterium X is a global charge CMOS that does not line scan, then we could use a mechanical shutter to gain some of the image properties of film. So we could re-introduce shutter-skew and temporally shifted motion blur and many things that suck about mechanical shutters and film, that for some reason many people want to duplicate.

FWIW, I don't believe the upcoming Mysterium X will be a global shutter or globally charged, non-scanning sensor. Jim made a post around here a while back that said the upcoming sensor would greatly improve the photosite response rates and would lessen the skew effect.

[Davide B.]

With the Global shutter you set all pixels to gather charge then open the mechanical shutter, hold open for a while, then close the mechanical shutter, then start the "rolling" readout. Since the mechanical shuter is closed during the readout there is no visable rolling shutter artifact.

The artifact from the mechanical shutter depends on its radius just like in a movie camera like the Mitchell NC has a larger radius than an Eyemo. You can use two counter rotating shutters to get a faster open and close time.

Yes, I just meant that if the Epic has a rolling shutter and a mechanical shutter it'll still have RS artifacts. You Jeff, and I are in agreement that a solution would require both a global shutter and a mechanical shutter.

davide