Alexa XT on Steadicam Zephyr (low mode)

[Mark Schlicher]

Christopher,

 

Zephyr is not designed for used with heavy, power-hungry cameras. You may be best served to turn this job down if you can't convince production to rent a light b-camera, for reasons well-stated above. Consider Canon C300 with a PL mount, as another option.

 

That said, there are some ways to make the Alexa work on a Zephyr, possibly even with the lens you mention. I'm not saying you "should", especially if you don't have the kind of close relationship with the DP and/or director to have the kind of conversation that is necessary to manage their expectations about the rig.

 

First: Weight. The lens and camera body alone are close to 25lb. Slightly above the official camera payload but probably do-able, and very unlikely to damage the rig. As pointed out already, the accessories could tip you over the practical limits of the rig. Prep is crucial, to see if you are above the total lifting capacity of the arm. Lighter lenses would also help for sure.

 

Second: Stability and vibration. Adding the second battery allows you to keep the post short, minimizing flexing issues, and using the Steadi-Alexa bracket will help minimize potential vibrations. Sometimes vibrations with the Zephyr can happen because the connection between the post and topstage can get loose over time. Get in the habit of checking from time to time. Side note: Keep in mind that a heavy sled will have a lot more inertia than you may be used to, so the rig will behave differently.

 

Third: Power. The Zephyr can handle the power of the Alexa with a few important cautions. On a big rig you could just slap a battery on the back of the camera if you wanted, but you are already tipping the scales on a Zephyr, so you have to power off of the sled. 24V is preferred with Zephyr because it is less stress on wiring. Make sure to check your 24V cable to confirm it's wired for 24V and not 12V. If your monitor has a battery plate, consider running the monitor on its own battery. You will want DIonic HC or equivalent on the sled, to handle the high current draw. And you will want lots of batteries and charging stations. No matter the voltage, the camera draws a lot of current and you will go through batteries fast, especially if the batteries have a lot of cycles on them. The Bartech and focus motor take a surprising amount of current in addition to the camera's draw.

[Guest christoper]

Well thank you all for all the informative stuff you gave me, I managed to convince them to use the zeiss high speed primes which weight around 0.5Kg

So if we do the math the total weight will be:

Alexa XT body 6.8 Kg

High speed primes 0.5 Kg

Clip On matt box with filters 0.6Kg

Bartech ff 0.4 Kg

Teradeck transmitter 0.2 Kg

 

The total will be 8.5 Kg which is within the range of the zephyr, so I guess I'll be safe for high mode but I wouldn't get away with low mode.

Anyways I'll test the setup in 2 days but for the shooting I'll rent a bigger rig if available.

[Mark Schlicher]

Why do you think that lowmode will be any different than high mode? There is no difference in capacity as far as I know...

[Thomas English]

I guess it is a bit scarier hanging the camera upside down. Well done swapping the lens out; Yeah In some markets sometimes DoPs need to compromise for the kit available on hand. Certainly I will tell a DoP not to use Primo-Anamorphics on Steadicam or do my very best to swap those lenses out. It is the nature of the beast.

 

Christopher, high a bigger rig.. but definitely test it out. It might be an idea to send a power cable up the outside of the rig. I had a Zephyr for a bit. You might get away with it or it could all end up in an embarrassing mess. Let us know. GOOD LUCK! land luck comes to those who are prepared.

[Alan Rencher]

In low mode, you have to extend the post much more than you would in high mode, so vibrations with each footstep become more pronounced.

 

[Mark Schlicher]

I guess I follow the logic but I don't see that extra extension is automatic...especially to the point where you "couldn't get away with it." Extending the post in low mode is a choice but is not necessarily required.

[Alan Rencher]

Mark, I've had to do low mode with the Zephyr near its weight limit on occasion, and in order to get an acceptable drop time, the post has to be lengthened.

[Mark Schlicher]

I'm just saying that post extension may be needed to drop the camera down to a specific desired low height, but nothing inherent about low mode that requires lengthening the post. Simply lower the gimbel and. voila.

[Victor Lazaro]

With a heavy payload, the bottom stage of the Zephyr being fairly light, you need to extend the post to get some clearance between the gimbal and the top stage.

[Mark Schlicher]

In my somewhat limited experience with lowmode and a heavy camera, the aux battery hanger with second battery does a good job of adding enough mass to keep the post short in either high or low mode. Without it, the extended sled is unwieldy either way.

[Michael Wilson]

If you can connect a piece of string from top to bottom it may help with vibration.

[Mark Baluk]

In my somewhat limited experience with lowmode and a heavy camera, the aux battery hanger with second battery does a good job of adding enough mass to keep the post short in either high or low mode. Without it, the extended sled is unwieldy either way.

Even with two batteries on the base, I find it quite impractical to operate with anything but an extended post when in low mode, and it definitely introduces a lot of vibration.

[Juan Lima]

Talking about the Alexa XT or the XT M?
Alexa XT is 14lbs. Alexa XT M head only is about 6lbs.
Follow motor add 0.5lbs.
Check again lens weight.

No matter High or Low mode. Not a job for Zephyr for shure. Talk with DP, get a smaller camera. But at this point you should already have tested the setup. How was it?

Edited April 29, 2014 by Juan Lima

[Sanjay Sami]

I just had a day of prep with the Alexa XT and the Arricam LT with Hawk Anamorphics lenses. The movie is shooting with film primarily and some sequences - night exteriors - will be shot Alexa.

I was surprised by how light the Alexa XT is. It is substantially lighter than the LT - which is kind of light anyway.

I had to dial down the arm a lot to get it right for the Alexa.

I always thought the two cameras were close in weight.

[Guest christoper]

I tried the setup, it was really good for high mode, but they needed a very low angle shot (kids playing soccer) so I didn't risk it. I gave the job to someone else with a bigger rig. Thanks you all for your replies, much appreciated :)