why RED TWO must have optical viewfinder and a rotating mirror shutter.

[najafi/didarfilm]

Hi all my RED friends.
have a look:

http://www.redhax.net/wiki/Understanding_Rolling_Shutter_Artifacts

sometimes ago, i just discussed on the necessity of a optical viewfinder and a rotating mirror shutter for RED. all reasoning for not embedding it into RED was for camera body size and also the price.
Jim had a long experience in Optics industry so I know he can make an affordable solution for that.

best
Hossein

[Evin Grant]

There will most likely never be a Red 2, just the evolution of the Red One. That being said feel free to void your warranty however you see fit when you take delivery. A mirror shutter is an interesting an antiquated solution to a problem that doesn't see to exist in Red footage. The rolling shutter in the Red moves so fast that pretty much all of the artifacts you're concerned with are non existent. The only issue I've encountered is with hi speed photo flash units exposing half frames, but this happens even on film cameras.

[Kevin Halverson]

An optical viewfinder, while nice, isn't really essential as look around is provided based upon the sensor being larger than the captured image.

A mechanical shutter would be nice in some situations, but the behavior of RED's electronic one seems to be fine for nearly any application other than impulse events such as the unsynchronized, short duration strobe event that is referenced. Even this type of shutter issue can be avoided by using a strobe duration that is longer and synchronized to the camera's shutter interval.

The additional cost and complexity of a mechanical shutter is substantial, adding an optical viewfinder would be considerable more.

[Antoine Fabi]

euh...

excuse my ignorance, but if the rolling shutter moves so fast, so is the equivalent shutter speed ?

What about normal and relatively slow shutter speed ?

thanks

[Kevin Halverson]

The shutter speed is based upon the interval between the beginning of subsequent frames, not the interval between individual photosites during the refresh cycles.

[I Bloom]

FYI, that's a wiki entry. Subject to change and review. Please do.

I think some kind of third party mechanical shutter box might be the solution to these problems.

I believe the electronic shutter might also create issues with certain kinds projection, televisions, and other things that strobe, but I'm still experimenting.

IBloom

[Jeff Kilgroe]

The rolling shutter has greatly improved since what we saw with Crossing the Line. IMO, there isn't anything a mirror shutter is going to provide here to benefit the image. I see better arguments for an optical viewfinder, but still don't think it's necessary with the look-around and various focus assisting tools.

[nzben]

Hi all my RED friends.
have a look:

http://www.redhax.net/wiki/Understanding_Rolling_Shutter_Artifacts

sometimes ago, i just discussed on the necessity of a optical viewfinder and a rotating mirror shutter for RED. all reasoning for not embedding it into RED was for camera body size and also the price.
Jim had a long experience in Optics industry so I know he can make an affordable solution for that.

best
Hossein

My understanding is that there is a spatial relationship between the back element of the lens, a spinning mirror, the low pass filter & the sensor. You can't put them all in together.

The genesis has no spinning shutter = no optical viewfinder.

The D20 has a spinning shutter, but no low pass filter (or the filter is too close to the sensor??) = dust resolving on the image a lot more. I haven't used the D20, so not exactly 100% on it's setup, but it is known to have more dust problems that the Genesis.

Some people also claim that turning the camera off when opening the port will reduce static around the sensor, resulting in dust being less being 'attracted' to the sensor. Any comments?

[jbeale]

Some people also claim that turning the camera off when opening the port will reduce static around the sensor, resulting in dust being less being 'attracted' to the sensor. Any comments?

If that is a problem, I'd think it could be solved by a thin conductive layer on the low-pass filter that is electrically grounded. There are conductive materials that are transparent in thin layers, for example indium tin oxide. http://en.wikipedia.org/wiki/Indium_tin_oxide

[Charles Angus]

Optical viewfinding is one reason I love film cameras. You can see through it without batteries. EVFs tend to be more taxing on my eye for a long period.

That said, the main feature of the OVF is the overscan, which RED delivers. I still would probably prefer optical, but its a slight comfort/convenience thing.

[Kevin Halverson]

The "new" cameras have the OLPF/IR-HPF located 8mm from the sensor plane as opposed to 2mm that was used in the original design. This is going to considerably defocus any dust that might be on that surface to the point that it should no longer due much more than add a minuscule amount of attenuation. This should really help to alleviate any 'dust' issues in real world applications. It won't effect any shutter characteristics, but its a really welcome improvement none the less.

[chuck colburn]

Hmmmm....8mm. Anyone know how thick it is? And no I'm not thinking about FFD shift here. Just would like to know.

[Stephen Williams]

Hmmmm....8mm. Anyone know how thick it is? And no I'm not thinking about FFD shift here. Just would like to know.

Hi Chuck,

Thinking about some of those Zeiss lenses that go very deep!

Stephen

[Kevin Halverson]

Hmmmm....8mm. Anyone know how thick it is? And no I'm not thinking about FFD shift here. Just would like to know.

Sorry, I don't know if its the same assembly in a new location or a new design altogether. This is a question that you would need to ask of someone at RED as I don't have a camera here right now. I suggest emailing Jon (jon@red.com) to see if he can get you an answer.

Kevin Halverson

[chuck colburn]

Hi Chuck,

Thinking about some of those Zeiss lenses that go very deep!

Stephen

Hi Stephen,

No not that. 8mm is just a hair over 5/16" so I don't see that as a problem as all mirror shutters impinge more than that. Might be nothing and no need to create worry where there probbally is none. Just would like to know. lol

[chuck colburn]

Sorry, I don't know if its the same assembly in a new location or a new design altogether. This is a question that you would need to ask of someone at RED as I don't have a camera here right now. I suggest emailing Jon (jon@red.com) to see if he can get you an answer.

Kevin Halverson

Thanks Kevin. Is Jon their optical man?

[Kevin Halverson]

Hey Chuck,

I can't say that he is "their optical man" (despite having a life time of experience in retail camera sales) but Jon does have access to the mechanical engineering guy(s) and would likely be the best one to get that information.

Keep in mind that they are all busy beyond description, so it might take some time to get you an answer.

Kevin

[chuck colburn]

Busy doing what?

Right now the last thing they need is someone asking for details of a componet of their camera, if they even handout such. lol
Mayby one of you guys/gals with one of the new versions could yank the filter out of the body and measure it with a micrometer. Don't screw the mic down to hard as these filters tend to be kinda fragil.
Only kidding! Really, don't try this at home. lol
Thanks Kevin

[I Bloom]

The rolling shutter has greatly improved since what we saw with Crossing the Line. IMO, there isn't anything a mirror shutter is going to provide here to benefit the image. I see better arguments for an optical viewfinder, but still don't think it's necessary with the look-around and various focus assisting tools.

Hey Jeff,

In certain situations, involving uncontrolled strobes, CRT screens, and DLP projectors, I have determined from tests that the Red creates artifacts that other video cameras do not. In these situations it would be beneficial to have a revolving mechanical shutter inside of the camera or directly in front of the lense (as long as it's out of focus) because it would soften the horizontal cutoff.

One system I'm considering is a flat black disk in a box that rotates in front of the lense, with a pie shaped slit. I believe this would be useful for concerts and other live shows where uncontrolled strobes will be common. The disk need only keep the sensor in darkness during the readout period and be sufficiently out of focus. It would need to be able to phase rotation relative to the genlock. A flickering transparent LCD panel might also do the job.

http://www.reduser.net/forum/uploaded/582_1198175434.jpg

If anyone is interested in manufacturing such a device, I'll be your first customer.

I have read that Claudio Miranda experienced other motion artifacts related to the shutter, but I have yet to see examples, I didn't notice anything like it in some jumpy carmount stuff I have. It is possible that protecting the sensor from light during readout could also solve these problems if they are what I think.

I'm not proposing that Red change it's current design... not at all. It's extremely cost effective and all we will need 99% of the time. I am suggesting that shutter artifacts are something that we should consider and understand, and that we can solve if we so desire in situations where it is appropriate.

IBloom

[chuck colburn]

Are you talking about putting a focale plane shutter in front of the sensor?

[Jeff Kilgroe]

Interesting concept there, ibloom.

I agree with you on the "shutter artifacts" exhibited by RED, but I'm not so sure a mechanical solution like this or even a conventional mirror shutter will do a whole lot to eliminate the effect, let alone eliminate it. I suppose it's worth testing.

I'm also interested to see if we get different motion and shutter characteristics with the new batch of cameras vs. the current 100.

I'm interested in negating these artifacts as well. Especially the split-frame effect of uncontrolled strobes, pyro effects or muzzle flashes. Some of this can be duplicated on film cameras as well, but the effect is softened -- actually no where near as sharply defined as on the RED. That's probably what you're aiming for. Other digital cameras that do not exhibit these effects are CCD sensor cameras that do not have a scanline "rolling" shutter, but rather a simultaneous read of the entire sensor array.

[Gavin Greenwalt]

But... if you add a rotating shutter in front of a scanline shutter.... how does ... wait... what? I don't think your gizmo would work unless used in front of a global shutter... in which case you don't have any rolling shutter artifacts anyway... I'm lost... wouldn't you just get a harsh horizontal line in addition to a soft vertical line?

[DAVID McNAMARA]

Optical viewfinding is one reason I love film cameras. You can see through it without batteries. EVFs tend to be more taxing on my eye for a long period.

That said, the main feature of the OVF is the overscan, which RED delivers. I still would probably prefer optical, but its a slight comfort/convenience thing.

I come from the film world as well. I love my RED camera but having just done a job with alot of low light, fast moving objects(f-18s) and long lenses I really really miss my optical viewfinder. Even the crappy one on my old arri 3 !

http://www.collectiveny.com/

[chuck colburn]

If you could put up with about a 30% light loss perhaps you could mount a pellicle beam splitter in front of the sensor. Mayby incorperate the OLPF into it and kill to birds with one stone.

[DAVID McNAMARA]

Chuck,
how would I do this? Are we talking similar to a Bolex?

[chuck colburn]

Chuck,
how would I do this? Are we talking similar to a Bolex?
Not the same. The Bolex Rx cameras used a prism block to divert some of the light to an eyepiece. A pellicle beam splitter is a thin piece of plano (flat) optical glass that is mounted at or around forty five degrees to the film plane and is partially silverd to divert light to an optical viewfinder. This was commonly done with motion picture camers that were not reflexed to start with or had not been converted to a spinning mirror shutter.
Think Cinema Products XR-35, early Panavision , Fries and others.

[Cail Young]

If anyone is interested in manufacturing such a device, I'll be your first customer.


It's a rain deflector but with a half-opaque disc.

The real trick would be synchronising it to the camera - I think you'd have more luck with your LCD screen concept - the Zscreen used in RealD systems could be a good starting point...