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Alexa Mechanical Design


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#1 ron goodman

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Posted 12 December 2010 - 08:32 PM

Some companies apparently still think they can apply the mechanical layout of a broadcast camcorder into 4 and 5K high level image capturing instrument and actually compete. Nowhere recently have we seen the shortcoming of this approach more than in the Alexa. The camera is a long as a city bus, (for reasons unknown),and seems to be catering to the news channels by adding a shoulder recess rather than taking the high ground and targeting a viable replacement for the film camera as others have. As someone who must integrate these cameras on remotely controlled mountings, I must express my frustration with the out-of-touch designers such as the Alexa mechs who insist on continuing to employ the wimpy wedge plate base attachment of camcorders from the Watergate era. The only mech designers to have got it right, in my opinion are the Red guys.....two 3/8-16 bolts on a wide solid base giving many mounting options. A strong wind could strip all those little screws right out of an Alexa body and send it into the ocean, never mind mounting it on a camera car, in fact the carrying handle has more structural integrity than the mounting base. This simply is not right....there.... got it off my chest..
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#2 David Mullen ASC

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Posted 12 December 2010 - 08:48 PM

I actually disagree with you, the basic ENG camcorder shape is well-suited for handheld photography, and isn't so bad on a tripod either.

We've reached a day and age where ever-shrinking sizes have produced sort of a dead-zone between a camera light enough to be held for long periods by the palm (and even then, there are real stability problems with handholding a palmcorder smoothly, as anyone who has walked around with a DSLR in video mode can tell you) and a camera large enough to balance properly on a shoulder -- the ideal being the Aaton 16mm cameras, ENG camcorders, and the ARRI-235, something where the center of gravity falls on the top of the shoulder and is long enough for the eyepiece to reach the eye properly and to grab it in front.

The only other solution is to basically take a small camera and throw a lot of counterbalancing weight at the opposite end, with the battery usually, which is how something like the Epic will work in handheld mode.

Cameras like the F35 and Genesis, though roughly shaped like a 35mm camera like a Panaflex, as basically boat anchors on your shoulder, possible to balance but much too heavy overall to be comfortable -- and take the SRW1 deck off and you have balancing problems.

So I think the Alexa is a good compromise in size and weight, any smaller and it would have to be basically a small box with a lens on the front and a battery and maybe digital drive of some sort mounted way in the back, and nothing in between on the shoulder. Of course, eventually all cameras will probably get smaller and need to be approached that way, but as long as you are in this rough size & weight range, the kidney-shaped camcorder design makes the most sense. Just because it's been used for decades by ENG people doesn't make it inherently a bad design, these guys spend many hours with a camera on their shoulders.

There are limits of course to the horizontal shape, you don't want it to be like the F900 with the batteries and HD-SDI converter on the back and a long zoom in front, like swinging a 2x4 around (but I'd still rather handhold an F900 than an F35...)

At some point, you want to be able to add accessories on the sides or top instead to reduce the length, which I believe is possible with the Alexa. But if they had taken the basic elements and squished it horizontally and thus made it taller and fatter instead, then a lot of work has to go into designing a handheld rig that counterbalances that properly.

At this point, I think their only option is to go smaller overall like the Epic will be.

Now as to why the Alexa is box-shaped instead of kidney-shaped, apparently that's partly due to lowering the costs of the circuitry inside, and the cooling system, it's basically easier to design electronics, with ease of swapping boards in mind, to fit into boxes instead of rounded shapes.
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#3 Brian Drysdale

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Posted 13 December 2010 - 03:38 AM

The RED One isn't the easist hand held camera and it was the 3rd part manufacturers who came up with solutions. Remotely controlled cameras often have different requirements to a camera that is both used on tripods and handheld. I imagine Arri did discuss with various people about layout and I suppose the box shape was the one that ticked the most boxes, although it's rather large for your purpose. A number of people were hoping for an Arri 235 type layout.

The Epic does get longer when you start adding modules.
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#4 Phil Rhodes

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Posted 13 December 2010 - 03:45 AM

I'm with Mr. Mullen.

I've always been horrified by the design of film cameras which seem invariably to be boxy and square and absolute agony to perch on one's shoulder. I don't see the problem with putting a shoulder pad on the bottom of it; it can just sit there between the tripod head and the camera when it's not in use, with no harm done.

I could expand on this by saying that I really don't like using movie lenses handheld either - on more than one occasion I've felt like the focus problems weren't due to my inability to see focus adequately, they were simply due to my inability to rotate the lens through 500 degrees quickly enough with one hand.

Nevertheless I don't think Mr Goodman need lose any sleep over this. It has long been the standard assumption that film things and film people are "better" and video things and video people are "worse" and I shouldn't think for a second that any usability improvements on Alexa will be much more than a glitch in this long-established status quo.
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#5 georg lamshöft

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Posted 13 December 2010 - 03:47 AM

The basse plate has two 3/8" threaded holes as well - so your concern is the short basis - levering out the camera by adding force at the back or front?

As far as I know, the base plate is machined steel, 3 times stiffer than aluminium - when it's attached correctly and made out of high-quality materials (chinese crap screw flood the market) - and this is the last thing I would worry about with ARRI - it would be hard to rip it off or damaging it. They regulary mount it that way even with gigantic lenses. If you still don't trust the short base, there is a second attachment point at the back, used by adapters like the ARRI QR-HD-1 - there are other solutions as well, just ask ARRI.
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#6 David Mullen ASC

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Posted 13 December 2010 - 12:15 PM

I could expand on this by saying that I really don't like using movie lenses handheld either - on more than one occasion I've felt like the focus problems weren't due to my inability to see focus adequately, they were simply due to my inability to rotate the lens through 500 degrees quickly enough with one hand.


Well there I have to disagree with you, the only reason for a short barrel rotation on an ENG lens is for the operator to focus while operating, which is just something I rarely do on handheld shots for movies, it's easier to concentrate on the operating if there is a focus puller dealing with the focus (ideally with a remote). Of course, if the focus-puller is off, then it's frustrating for the operator if there is a remote on because now he can't just grab the wheel and correct it.

For me, the biggest advantage to ENG zoom lenses for handheld work is simply that they are small, lightweight, and easy to hold... though I'm sure the short barrel rotation helps in designing the lens to be smaller. But I'm not so fond of the design drawbacks, such as the short rotation but also the breathing and ramping.

But I'm definitely with you that it's just silly to write-off or dismiss ENG design philosophy as somehow "inferior" to cine design when it has some real practical advantages (which is one of the reasons I think that Lisa Weigand switched "Detroit 187" from the Red One to the Panasonic 3700 when she took over, being easier to shoot that show in a handheld doc style with ENG cameras and lenses.)

The two problems I have with short barrel rotations: focus racks are very hard to make smooth & elegant, but instead are jumpy & snappy, it's hard to get the focus to "roll" into place. Second is just that it encourages focusing by monitor or eye because the distance marks are too closely spaced to allow accurate focusing by measurement, so focus-pulling becomes "reactive" to action rather than anticipatory, the sharp focus tends to fall a split-second after the movement settles down. Now with the deeper focus of 2/3" sensor cameras, these problems are less obvious because depth of field covers some "slop".

If you are running around handheld with a cine lens and need more than one full barrel rotation to get the subject in focus, that's pretty rare to be that far off in the first place, that's more of a focus rack from one object to another.
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#7 Mitch Gross

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Posted 13 December 2010 - 12:39 PM

I think the design of the camera is pretty good. What at first appears as a box quickly reveals the ease and straightforwardness of a layout that really thinks about the operator and how he will integrate with the technology. For handheld use (yes, some people do like to shoot handheld on occasion), the cutout out s the lens below eye level. Excellent. A battery mounted on the back will balance nicely with a prime up front.

For tripod mounting there are two options. For a video-style V-plate, get rid of your ancient Sony VCT-14 or Panasonic equivalent. Those things are old news and have lots of wobble. Instead try a modern Chrosziel or even better ARRI quick-release plate system. The design of the mechanisms holds the camera in place like a rock. ARRI's is called the DigiCine Baseplate system and I can assure you it's worth it.

One can also remove that steel plate and instead go to a standard studio brigdeplate system in 15mm or 19mm.
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#8 Neal Norton

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Posted 13 December 2010 - 10:30 PM

With an Arri Ultra prime the Alexa camera is very very nice hand held. The Alexa is better on my shoulder than any 35mm sound camera I have used. . . I haven't worked with the Aaton, I think the 235 is the best handheld camera I have used. The Alexa is light (comparatively to the sound cams) and the CG is low which is great. The cut-out proves that Arri actually considered a human shoulder and not just ease of mounting or keeping the costs low - Thank You Arri!

As to mounting on a remote head, what camera are you looking at? The Alexa is compact and low profile and with the exception of being power hungry is a remote head techs wet dream. Would you prefer the huge and heavy and hot and loud wide and high F23/F35/Genesis Sony mess? Or the tinker toy flopping all around with hinges tubes and duct tape and cable rats nest of a Red? The 35mm sound cameras are all heavier and wider and have mags of some flavor that have to be reloaded regularly. Even a 435 is tougher to deal with on a remote head.

The mounting points on the Alexa are plenty well engineered for the job they do. If you would like to see small mounting screws then check out the 3 tiny allen screws that hold all Panaflex cameras on to the head. And I haven't seen a Panaflex shear off a head very often. All mounting hardware can fail. . . thats why every time a camera goes on a remote head the camera is secured with a secondary safety attachment. . . right?

Sincerely,

Neal Norton
Camera Operator
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#9 Alfeo Dixon

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Posted 24 December 2010 - 02:16 PM

I haven't worked with the Aaton

Now there's a wet dream on your shoulder, Neal! Low profile and just sits up there purrrrring along... but I'd say I was a bit surprised when i say the box'ish design on the Alexa, but I knew Arri wouldn't let us down like the clunky D-21

-Alfeo
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#10 Jamie Metzger

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Posted 10 January 2011 - 09:59 PM

I've seen the Alexa balance on someone's shoulders, hands-free, right out of the box with an Ultra Prime on it.

It's a beautifully designed camera.
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