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Arri Alexa power cable


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#1 BJMcDonnell SOC

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Posted 25 October 2010 - 01:39 PM

Hey Guys,

I have a feature coming up and I need to know if I need a special power cable from my PRO2 to the Alexa for power. Also do I need a different run stop cable from my Preston to the Alexa. Any knowledge would be rad. Haven't flown it yet so tips I'm all ears. Thanks y'all .I have all the cables obviously to power any Arri film camera so can I just use one of those?
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#2 Stefano Ben

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Posted 25 October 2010 - 02:18 PM

Hey BJ

Talked about it on this previous Topic!

http://www.steadicam...536

Have a nice work with Alexa!

Best, Steve!
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#3 Benjamin Treplin

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Posted 25 October 2010 - 06:32 PM

Hi BJ,

you don't need any new cable for the Alexa. Power and RS plugs are the same as with any other 24V Arri camera. The one thing you have to check is what kind of adapter bracket comes with the camera. There are three different ones: a V-mount, a bridge plate and a flat bottom adapter.
Have a look at http://www.arridigital.com/downloads Alexa usermanual page 32 and 33.
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#4 BJMcDonnell SOC

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Posted 25 October 2010 - 07:31 PM

Thanks a lot guys. This is what makes this forum great. Peeps helping out peeps.
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#5 Jeff Muhlstock SOC

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Posted 27 October 2010 - 08:09 AM

Hey Guys,

I have a feature coming up and I need to know if I need a special power cable from my PRO2 to the Alexa for power. Also do I need a different run stop cable from my Preston to the Alexa. Any knowledge would be rad. Haven't flown it yet so tips I'm all ears. Thanks y'all .I have all the cables obviously to power any Arri film camera so can I just use one of those?



Hey BJ, your going to love this little camera! Im on my 4th week with it and Arri has finally done it. Great camera, all ARRI! same cables. We record on the cards only for Steadicam and we use a fiber box for recording dual link to tape for all the rest (cards become our backup record) Nothing really new to learn here, you need an HD monitor or downconverter (no built in downconverter).

Low mode plates are rare at this time but the next software update will have an Image invert feature so it will become a flipped camera, easy... For now, I am recording upside down and flipping the image in our card to tape transfer, still no big deal.

Overall, I really love this camera. I think Arri has brought on the death of Film, this camera is that good!

Cheers,

Jeff
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#6 BJMcDonnell SOC

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Posted 27 October 2010 - 10:26 AM

Hey Jeff,



Im pretty excited to use this camera especially after just getting off a 3D shoot yuck!!! Thanks for the info.
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#7 MarkKaravite

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Posted 29 October 2010 - 10:59 PM

Hey BJ,

I just prepped an Alexa for the first time today for a show starting Monday. All the above comments are correct. On the camera I'm using, the Anton Bauer plate didn't have a P Tap, so AKS power was scarce. The rental house had a plate that sandwiched between the battery and the AB gold mount that had 4 P tap outlets. I wedged some velcro in between the plates to take out the slop. I need a P Tap for my Decimator for the downconvert. I'm gong to start by flying a Dionic on the back of the camera. It will power the camera as well as the P Tap. It's still very light, even with a battery on board. I considered putting the Arri baseplate between the camera and the donkey box to have more mass, but I'll try it like this for now.

There are 2 Arri 3 Pin RS connectors on the camera, so those are available for Preston stop/start & one other AKS. I believe the camera is a native 24v camera, but you can feed it 12v or 24v. The camera upconverts the voltage to 24v when fed 12v. I assume the RS connectors would have 24v AKS power available no matter what voltage you feed the camera (because of the upconverted voltage). Does anyone know this for sure?

I also plan on shooting with the camera upside down for low mode and flip the image in post. It's a bit of a hassle for video village, but better than having vibration through a poorly mounted dovetail on the handle.
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#8 Lawrence Karman

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Posted 30 October 2010 - 11:46 AM

I have not used one yet and I'm not clear on one thing: Can we mount our dovetail plate directly to the camera bottom or do we need some type of adapter plate to create a long flat base to screw into? The camera bottom is curved, so is it necessary to bridge that or is there enough real estate under the front to attach a plate?
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#9 Charles Papert

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Posted 30 October 2010 - 01:00 PM

Screwing into the bottom of the camera is fine, no issues. The Alexa I've been using has a long flat top handle with the expected threaded holes so attaching a low mode plate is not an issue. I thought it was standard issue...Mark, yours doesn't have this?

Also Mark, on your power issues: I recommend getting a power Lemo from the junction box to female p-tap cable made up. It's saved me a number of times in the last few years so it's a worthwhile investment. You can power any p-tap accessory via the sled instead of having to rely on an active port on the camera or flying a battery just to power an accessory. Some have used the 4-way p-tap breakout box that AB makes at the end of this cable; not a bad idea but can be bulky if you don't need more than one port, and they are prone to splitting so I prefer to have the stock version that I can plug into my cable as needed. Terry West can make either for you.

Otherwise, maybe consider getting a power cable for your Decimator to power off the sled directly. By popular demand, I am now stocking these as well as p-tap power cables for the Decimators in the 4 pin power/video Lemo size compatible with PRO and XCS sleds (Tiffen Hirose version available on request). These as well as the P-tap version are $135.
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#10 Alec Jarnagin SOC

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Posted 30 October 2010 - 01:09 PM

"I recommend getting a power Lemo from the junction box to female p-tap cable made up. It's saved me a number of times in the last few years so it's a worthwhile investment. You can power any p-tap accessory via the sled instead of having to rely on an active port on the camera or flying a battery just to power an accessory. Some have used the 4-way p-tap breakout box that AB makes at the end of this cable; not a bad idea but can be bulky if you don't need more than one port, and they are prone to splitting so I prefer to have the stock version that I can plug into my cable as needed. Terry West can make either for you."

Words to live by. Same set-up here.
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#11 MarkKaravite

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Posted 31 October 2010 - 09:12 PM

Hey Charles,

I had never thought of that, but a great idea to have P Tap power from the sled. I'll give Terry a shout for that cable. Please email me directly at mkaravite@comcast.net with ordering info for the cable from PRO sled - decimator.

I'm going to start by carrying a Dionic on the back of the camera anyway. It's so light, I like the extra weight there. Plus, our UPM is so cheap, he nixed my order for 9 Dionic 90's to run the camera on Steadicam. The 1st AC managed to acquire 4, so I'm running the camera from the on board Dionic. As a matter of principal, I've always had the rental house provide batteries for these power hungry digital cameras. I've managed to get long life out of my current Dionics, because they only run film cameras. Panavision seems like one of the only rental houses that doesn't balk at providing ample battery power for Steadicam Ops.

Sorry about the battery rant. Shoot me an email.


Thanks,
Mark
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#12 Thomas Schnaidt

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Posted 17 February 2011 - 09:40 AM

Bj-

You have probably finished your job with the Alexa, just curious what your experience was with it. I have just picked up a Pilot using the Alexa and need to get all the info in advance I can.

Thanks

Tom Schnaidt,SOC
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www.steadytom.com
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#13 Fabian Roesler

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Posted 19 February 2011 - 06:37 AM

Hi there,
i have just finished a 2 months feature with the alexa. We were shooting in Kiew and Berlin in the cold season and i must say the camera behaved very well. Updates are constantly released so every 2 weeks there is improvement in the handling. Alexa can record on the cards in 4:2:2 now. So no more cables. It can run 48 fps also on the cards. If i am not mistaken they released an update some days before activating the playback button. We didn´t install this one because it came with a complete new internal colour management and we only had some shooting days left. We didn´t want to change anything in the look during production.
The cold was never an issue (also because of an update some weeks ago) minus 20 degrees centergrade was fine for the machine. We even smashed the camera on the ground, when the DOP was running hand held and didn´t see an obstacle. Even this hit didn´t cause any malfunction.
Make sure to get the right accessories, like the low mode plate, this base plate adapter, and the p-tap adapter. I had the alexa on the steadicam with an on board batteries on the back, which is perfectly fine and far away from heavy. Our version had two batterie mounts, the second one on top of the camera. So if you like the camera to be a little heavier you can add a 2 nd batterie.
There is a lot to say about the camera so if you have specific questions let me now. The support by ARRI is a dream, at least here in germany, because this is their baby now. The web support works great. You can download your prefered frame lines and copy them to the camera. Sounds difficult, but was really easy and done in 15 minutes.
Picture quality is stunning and handling and ruggedness made working with this camera a dream.
all the best
Fabian
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#14 Ramon Engle

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Posted 27 February 2011 - 02:35 PM

Does anyone know the Fischer Part # for the 2pin power connector for the Alexa. I know its the same as the stardard 24volt Arri connector. I need a right angle version to fit in the Alexa and not interfere with the Camwave.

Thanks
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#15 Kar Wai Ng

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Posted 27 February 2011 - 06:14 PM

Does anyone know the Fischer Part # for the 2pin power connector for the Alexa. I know its the same as the stardard 24volt Arri connector. I need a right angle version to fit in the Alexa and not interfere with the Camwave.

Thanks


http://www.steadicam...?showtopic=6535

There are some part numbers in that thread that might get you on the right track to finding the right-angle version in the Fischer catalogue.

http://www.fischerco...atalogue_v1.pdf
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