Cinematography Mailing List - CML



435 Shutter phase

class="Body" I am told there is a 3rd party EPROM for the Arri 435 that will allow user control of the shutter/movement phasing through the use of the RU-1 controller. (a la "..Private Ryan") Is anyone familiar with this "chip" and who is making it or where one can purchase it? I know several rental houses in LA are providing this as an option, though with many, many caveats. Has anyone here used it? Inquiring minds want to know. --

class="Body" Rod Williams

class="Body" First Camera Assistant Petaluma, CA USA

Rod Williams wrote :

> I am told there is a 3rd party EPROM for the Arri 435 that will allow user control of the >shutter/movement phasing through the use of the RU-1 controller. (a la "..Private >Ryan") Is anyone familiar with this "chip" and who is making it or where one can >purchase it?

I have used it on a couple of jobs. It is easy to set up after the special EPROM chip is installed in the camera. You have to shoot some tests to get a feel for the results, as of course you can not see the result while you are shooting either in the viewfinder or in the video tap image.

The smearing effect works best with a a few bright items in the frame against a generally dark background. That way you can see the smears of the bright items against the contrast of the darker background. If you have a bright background, the smears will be hard to see, if not even visible.

The camera makes scary juddering noises while you are changing the shutter / movement phase while the camera is running, but Arri assured me that everything was OK, and indeed it was. It sounds like grinding parts, but it isn't, you hope!

I would recommend that you remove the special EPROM chip after using the camera for that job as you wouldn't want the smears when you didn't expect them.

One way to test to see if the system is working while on set is to use a "cine strobe" light to view the phase position of the shutter relative to the film movement while the camera is running. Of course you can not see this relationship while the camera is stopped because in the Arri 435, the shutter and film movement are driven by separate motors and will freewheel relative to each other when the camera is stopped. But, it is this separation that enables this smearing "trick"

One word of warning, when using the cine strobe as illumination when the camera is running, it will appear that the shutter is not moving. DO NOT forget yourself and stick your finger into the lens opening when the camera is running! The high speed spinning mirror / shutter will chop the end of it off, even though under the strobe light it appears to be stationary. Ouch!

Have fun!

Bill Bennett DoP Los Angeles

There is a "maintenance mode" that lets you put the shutter and pulldown out of sync.

I suspect that this is what you're referring to.

I'll leave it for someone more technically capable to explain how to do this


Geoff Boyle FBKSTS

Director of Photography EU based CML List Owner & Sysadmin

Geoff writes :

>There is a "maintenance mode" that lets you put the shutter and pulldown out of sync

With respect, this isn't quite correct. There is a maintenance or service mode which will let you run either just the shutter or just the movement on their own but not together, out of phase.

Separate from this service mode trick, there is also (as Rod Williams first posted) an Eprom for the camera which, in conjunction with the RU1, lets you alter the shutter/pulldown relationship, in shot, by anything up to 170 degrees in either direction. This chip was written by Arri Austria (the camera's designers) at the request of Arri Media some years ago. As is the way with software, this is now out and about in the big wide world.

The caveats I would stipulate when using this software are: 1. Test to detirmine what setting gives you the effect you want. and: 2. Be aware that this is a special version of the V1.57 eprom, so any features introduced since then are missing. These include refinements to the ramping behaviour and the Integrated Capping Shutter.

I think Bill is being a little overcautious in saying you should remove the phase chip when shooting normally. With the RU1 disconnected you are definitely safe. When the phase shift is active the whole display flashes, so it's pretty obvious.

Hope this helps,

class="Body" John Duclos (Technical Manager)

class="Body" ARRI MEDIA 4-5 Airlinks. Spitfire Way, Heston, Middx TW5 9NR, England http://www.ARRI.COM

John Duclos wrote :

>With respect, this isn't quite correct.

I stand corrected

I was also speaking to Simon C today and he corrected me as well.


Geoff Boyle FBKSTS

Director of Photography EU based CML List Owner & Sysadmin

I recently used a special eprom chip while shooting in europe that left the shutter completly open during shooting. Effectively, it was as if I had no shutter. We would line up the shot, then the assistant would punch in a specific combination of buttons and the mirror would rotate out of the way of the film plane. Of course we could not use the reflex viewing nor the tap while shooting. All of this was done without the RU unit. After arriving home I inquired about the chip being available in the states, and was told by someone at Arri the following:

"We are very concerned that someone may leave the special EPROM in, and then shoot something without realizing what a crazy effect they will get, so we make this EPROM only available when customers specifically ask for it. I believe that in the US, at least CSC in NY, the Clairmonts, Otto Nemenz and The Camera House in LA should have it or be able to get a hold of it. "

So, I beleive that Arri is the manufacturer and you should be able to get it at most larger rental houses.

CMLers Many thanks for the (as usual) friendly and frighteningly knowledgeable response to my inquiry about the shutter phasing technique with the Arri 435. I've passed the info along to a local Arri rental house here in San Francisco and they've ordered the chip to install in one of their cameras. They were so happy to find a use for the old RU-1 in the back of the accessory drawer. I'm looking forward to shooting some test soon. Thanks again. --

Rod Williams First Camera Assistant Petaluma, CA USA

I haven't read all of the message concerning this thread but you don't need a special Eprom to run the camera with the mirror _not_ turning. It's a diagnostic setting, that also happens to give the temperature of the camera! :-) Perhaps this diagnostic feature was somehthing that was added to later Eproms. There is also a not very useful for us setting where the mirror spins without the film movement turning.

I don't have the button sequence handy but will look for it ....

Mako Koiwai

>There is also a not very useful for us setting where the mirror spins without the film >movement turning.

Mark "RP IS still viable, darnit" Weingartner

VFX and Lighting for Motion Pictures LA based but in NYC

As several poeple have mentioned, it is possible to run the camera movement only without the need for special eproms, however the eprom method is a lot better. Consider the following:

With the service mode method you have to line-up your shot, remove the lens, move the shutter out of the way manually (naughty), replace the lens and then shoot with no look through or video assist. This route is all or nothing, you don't get to introduce it during the shot. Also, because pulldown is pretty rapid on the 435 you don't get as much smear as you might imagine. With the eprom, at greater phase shift angles, the shutter is covering some of the static part of the exposue which helps exaggerate the smear effect.


John Duclos (Technical Manager) ARRI MEDIA

In projection, if the shutter does not cover the entire pulldown of the film, the smear is called "travel ghost". The amount and direction of the streaking will depend upon whether the shutter timing is early or late, and the shutter angle. Most 35mm and 70mm projectors use "Geneva" or "Maltese Cross" intermittent movements to achieve the pulldown, which typically require 90-degree shutter blades to block the light during pulldown.

John Pytlak

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