Arri WCU-4 paired with Alexa Plus?

Mark Kenfield · April 13, 2016

Hi guys,

I'm wondering how people find the Arri WCU-4 paired with the CLM-3/4/5 motors and Alexa Plus/Studio?

Is the performance up there with the other big boys like the Prestons? I really like the idea of only having to add the lens motor and cable to the camera, and keeping things lighter and more streamlined.

Cheers,

Mark

Miguel Angel · April 13, 2016

I am currently working with an Alexa Studio + Arri WCU 4, all hand-held and long takes.

I really love that there is no extra weight on the Alexa (Preston brain) but the focus pullers are having some problems every now amd then with the motors because the clamp which has to be attached to the rods keeps getting loose so they have to tight it and then calibrate the lens.

I think the problem comes from the clamp itself which has an ellipsoidal shape rather than a circular one.

I have been a "Preston boy" since I was a 2nd ac, then, Arri released the WCU4.. I like not having the extra weight on fhe camera and everything works really well.

Have a good day.

Mark Kenfield · April 13, 2016

Thanks Miguel, which of the motor models are you using that are causing some grief? Is it the CLM-4s?

Miguel Angel · April 13, 2016

You're welcome!

CLM-4s.

It is very weird because I have used CLM-3, 4 and 5 before and never had a problem but the 4s in this movie are very temperamental! :D

Anyways, I highly recommend the WCU-4, you will be happier and your back will live longer! :) and get the Blue Modular Kit too if planning on going hand-held, I'm using the O'connor grips and although they are super super good, they are very heavy.

Have a good day!

Ben Rowsell · April 14, 2016

"I really love that there is no extra weight on the Alexa (Preston brain)" "you will be happier and your back will live longer!"

Something that is often overlooked:

(apart from an Alexa Studio, as it is always a Plus camera) On other Alexas the Plus is heavier than a non-Plus: e.g. Alexa XT = 6.6kg, Alexa XT Plus = 7.3kg. Thats 700g more on the camera body to get the integrated system working, which is heavier than a 3 or 4 channel Preston MDR.

There are also options for motors that are lighter than the standard Arri CML4s, etc. Even using the Arri UMC4 system (external brain) on a non-plus camera is significantly lighter. And you can run a single channel system for even less weight.

Just saying.

Ben R

Miguel Angel · April 14, 2016

That's very true and something to be considered if you can choose the camera.

In regards of the integrated system, I like it because it is so well done that it makes the camera really well balanced, something that sometimes is difficult to get when you have a Preston / UCM brain, mini monitor and Teradeks living permanently on the camera :)

Have a good day!

Dom Jaeger · April 14, 2016

There's a WCU-4 kit at Cameraquip Melbourne you could check out for yourself Mark, on a Studio or Plus. Give 'em a call to check it's not out on a job, and organise a time to drop in.

I'm usually there Mondays and Tuesdays if you want a chat.

We've found the system excellent, I can only see it becoming more of an industry standard as more people get experience with it.

Mark Kenfield · April 15, 2016

Cheers Dom, I think I'll do just that.

Miguel Angel · May 3, 2016

Quick update!

I was talking to a 1st ac friend of mine who is working on a feature at the moment with the WCU 4 and he told me that there is a problem in the distances when mapping lenses and pre-marked rings so that would be something to take into consideration and worth checking to see if it happens very often.

In the movie I just wrapped we were working with blank rings where the 1st AC's wrote the distances for each lens so we didn't have that problem.

Have a good day!

Satsuki Murashige · May 3, 2016

Interesting Miguel. So you're saying the mapping software is off and the marks don't line up on the hand unit? That would seem to be a massive problem, especially when shooting film.

Miguel Angel · May 3, 2016

I haven't experienced that because we were working with hand-marked rings but my friend is experiencing exactly that at some extent with the pre-marked rings.

If it is just the lenses that they are using (Master Primes) or if it happens with all the lenses I can't tell but I thought that it would be something interesting to share with Mark as he was asking about it :)

Have a good day.

Dom Jaeger · May 3, 2016

I'd be careful to assume that one incident indicates a systemic problem. Every lens needs to be individually set up, it could easily be a problem caused during the set up, a user error or simply a one-off electrical fault.

Many cinematography lenses are hand-scaled, Zeiss use different scales to accomodate small differences in manufacturing and assembly, so it's not just a case of entering "Zeiss Master Prime 50mm".

At any rate, we haven't encountered any problems with the system.

Satsuki Murashige · May 4, 2016

I just spoke to an AC prepping an Alexa XT and WCU-4 in the next bay over today and he confirmed the issue, for what it's worth. He was using Ultra Primes, and said it didn't matter if the lens data was calibrated and saved for that specific UP lens, the marks were still slightly off.

Mark Kenfield · May 4, 2016

That's for the pre-calibrated lens scales right? So if your AC is going through the specific lens set you're using for a shoot and calibrating each one manually, there shouldn't be a problem... have I got that right?

Miguel Angel · May 4, 2016

Pre-calibrated lens scales, right.

We had hand-marked scales per lens in the movie I just wrapped and didn't have any problems.

Hence the only thing you need is X amount of blank scales and time in prep for your 1st AC to write the scale manually per lens in each scale.

Have a good day.

Mark Kenfield · May 4, 2016

Cool, thanks!

Satsuki Murashige · May 4, 2016

That's for the pre-calibrated lens scales right? So if your AC is going through the specific lens set you're using for a shoot and calibrating each one manually, there shouldn't be a problem... have I got that right?

Yes, the pre-marked rings.

Mark Kenfield · May 9, 2016

Well I just dropped off a lens to Dom for fixing, and got to have good look at the Studio paired with the WCU-4. Have to say, I really like the setup, the simplicity of the rig is really nice, and putting my eye up to the optical viewfinder was just a delight - so much nicer than looking through the EVF (I tried both) though you do notice the added weight.

Paired with my 28-80mm CZ.2 an MB-15, a battery and a single motor for focus we weighed the full package in at 18kg. It's certainly a hefty load on the shoulder, but a very nicely balanced one.

The WCU-4 is super cool though. This is how all cameras should be able to be run I reckon.