Rolling Shutter Fix: Tessive Time Filter

[fotojohni]

http://tessive.com/

The price recently dropped to under 2K, this is a novel way of dealing with rolling shutter and it improves the over all look of each frame as well.  The reason for this is that it ramps the shutter open over a period of time, rather than opening it up all at once, or in the case of dlsr's, all at once but progressively, line by line.  The result is that light trails and other strong lights have less of a hard stop to them. 



The only thing we need to allow this to work on canon DSLRs is a genlock function.

[fotojohni]

Basically, if you pop an anti-aliasing filter in your canon and put the time filter on the front, you have a professional level 2K camera.  No rolling shutter, no moire, no aliasing.  The filter does attenuate a stop of light, but that's hardly an issue for the 6D or 5D3.  Pretty much with these simple fixes an indie filmmaker would have a camera that is perfect for shooting pretty much any kind of film.  That's the dream right?

I'm going to send an email to the founder of the company to see if he might provide one of these to key developers in the magic lantern community.  A1ex and 1% come to mind.  I'm sure many users of magic lantern would be willing to shell out $2K for an upgrade that would make the camera basically no different from a cinema camera.  I would consider the investment to be vital if I shoot my upcoming thriller this summer. 

Currently the time filter will not work with DSLRs because of the lack of a genlock function, however, with magic lantern there may be a way to implement this.  I might consider making some adapters and selling them on ebay for this project.

Please let me know if this sounds interesting to you.

[g3gg0]

they need an output that is toggled on exposure start and on end?

[fotojohni]

they need an output that is toggled on exposure start and on end?

Exactly, the camera's shutter speed would be set to max, whatever that is 1/31 of a second for 24p.  The genlock function basically sends when the exposure begins and ends so that the lcd shutter of the time filter will be synchronized. 

I have no idea what form this signal takes, I'm almost positive that it's a standardized format.  I think it was explored a while back for 3D filming or HDR with two cameras, but the set up for something like that is tens of thousands of dollars and no one really cares about 3D outside of James Cameron.  A fix for rolling shutter that enhances the motion blur would be a game changer.

[fotojohni]

Okay, I've sent an email to the company, it might be a few days before I get a response but I might be able to get some of these for testing purposes to key developers.  If you would like to take part in this please PM me with your email and I'll add you to the list of contacts so that we can begin an email thread with the head engineer at the company.

[g3gg0]

well, we could use the CF/SD card LED as output. just attach an optocoupler and we get a signal.

[fotojohni]

well, we could use the CF/SD card LED as output. just attach an optocoupler and we get a signal.

Interesting idea.  One that an arduino may be able to decode, if we were to try a fix.  Of course it would probably be easier to handle if it never left digital.  I'm getting more information on the subject so I'll get back later.

The more I think about it though, those active 3D shutter glasses can be bought and modified, with the help of arduino and magic lantern we might be able to do this whole thing inhouse for under $100.

[trsaunders]

Another option is to detect the sync pulse on the analogue video out (e.g using an LM1881). This will probably lag behind the actual exposure, but hopefully by a constant amount that could be characterised for each camera.

[fotojohni]

http://www.ebay.com/itm/New-pro-4-1-4-x-2-Auto-Darkening-Welding-Lens-Filter-Shade-3-10-Fixed-10-/390546441587?rt=nc&_trksid=p2047675.m1851&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%26asc%3D163%26meid%3D6823276908918202036%26pid%3D100005%26prg%3D1088%26rk%3D4%26sd%3D360627053003%26

These are extremely cheap and might be able to be remanufactured into filters with the help of an arduino controller.  No response from the tessive crew yet.  This seems like a fun project, so if they don't get back to me soon I might just take care of this myself.

Unfortunately they start at din shade 3 which I believe is a 2 stop ND, and the dark is din 10 which I think is about 12.  I'm not 100% how the din number corresponds.

http://www.ebay.com/itm/Solar-Auto-Darkening-Welding-Helmet-Arc-MIG-Tig-MMA-Arc-MAG-mask-lens-56-/290884867334?pt=LH_DefaultDomain_0&hash=item43ba16d506

This is another option that can be darkened to about din 100 which is basically opaque.  I'm going to put this project on the shelf until college is over in a few weeks.

[fotojohni]

What could be cool is to experiment with ramping the shutter open, maybe starting closed and slowly opening then cutting off instantly, so that there is a hard front but a motion trail that gradually fades away.  Perhaps there could be a menu option for that in magic lantern.  The lcd also lends itself to various long exposure capabilities, such as taking long exposures in bright sunlight. 

The ideal senario would be to place the shutter inside the camera body, similar to the mosaic engineering filter.  Just have them both going at the same time, the system still relies on magic lantern being able to send the signal somehow, perhaps through some kind of lens mount focus confirm chip modification.  In this case the cameras would be aliasing, moire, and rolling shutter free.

[1%]

I see why they don't respond:

http://tessive.com/news/

[fotojohni]

I see why they don't respond:

http://tessive.com/news/

Wow, got them at a bad time I guess.  Wonder what's going on with that.

They were over priced anyway, I think the welding active shutter idea is workable.  The switching time is only 1/5000s, there's a lot that can be done with that, probably pwm fading isn't out of the question.  I'll be buying some later this year, I'll keep everyone updated when that happens.

[zachnfine]

Has anyone done any more research into ways of syncing external devices with the camera's frame rate? Just for curiosity's sake, I'm tempted to try and build my own LCD shutter using a lens from a pair of 3D glasses (would only be large enough to cover a very small lens, or to work on the rear element of a lens).