Video Released, Crowdfunding Underway For Axiom Open Source Cinema Camera

New submitter atagunov writes "Video clips have been released as crowdfunding starts for the world first open source cinematic videocam. "I am a filmmaker myself ... I would like to have powerful tools that I know to have full control over and that I can tune and tweak," says Sebastian Pichelhofer of Apertus. He is working on the Axiom Beta, the 2nd generation Apertus videocam, fully open sourced under GPL and OHL. It's not cheap compared to consumer-grade cameras, but being not-cheap hasn't stopped people from snapping up Joel Rubenstein's Digital Bolex.

Comments

Don't see the need

[JoeyRox]

The digital camera market for video is very competitive and so there are some great feature-rich cameras available for shooting cinematic video. Most notable is the Blackmagic Design Pocket Cinema (was on sale for $500 recently), the Panasonic GH2 ($400 used), GH3 ($600 used), and GH4 ($1700 new).

Re:Don't see the need

[Wescotte]

Phone camera sensors are generally not a good choice for filmmakers. They're small so shallow depth of field is not really possible and they are very noisy in low light conditions.

The Axom project is trying to provide module hardware to support the widest range of requirements filmmakers might have. Making it open source allows a community of developers to implement more features than would typically be possible at their price point as well as allowing for upgradability you don't see in a typical camera. If somebody invents a faster autofocus algorithm then the community can implement it on your existing hardware. Generally camera manufactures don't add new features after they release the product not because they can't but because there is no real incentive to do so. Every feature they choose to add is making the decision to not add another on a future product.

A closed source camera has limited resources but an open source camera has as much support as the community decides to give it and it doesn't take that many dedicated people to surpass the man power of even the biggest camera manufactures. So while it might not have everything you typically want out of the box there is a good chance it won't be that way for long.

Re:"compared to consumer grade cameras"

[se6astian]

Plus interchangeable lens mounts. The sensor is already 4K, the internal processing is entirely 4K, the outputs will be 1080p at launch but 4K output will definitely follow later on.

Re:"compared to consumer grade cameras"

[dgatwood]

The biggest problem I see with this is that the lens mount system appears to be purely manual. This seriously limits the lenses you can use, because these days, 99% of lenses don't have mechanical aperture control. They really need to have some sort of adaptable lens electronics in this thing, so that people can design adapters that actually support modern lenses, similar to the Metabones adapters for NEX. The absolute minimum requirement for such things is a set of electronic contacts inside the lens mount that are controllable through software.

I think if I were designing a camera system to be extensible, I'd make the lens contacts speak USB 2.0, with appropriate short-circuit protection for when the lens is being attached to the mount. That way, the adapters could be very basic USB controllers that speak a particular lens protocol, rather than having to convert one arbitrary lens protocol to another (potentially incompatible) protocol.

There is one caveat to using USB, though. You'd need to also provide a 7.2VDC pin on the lens mount. Many camera lens systems require that much voltage to drive the focus motors, and it would suck to have to boost the voltage from a 5VDC USB supply in an adapter, particularly given that you probably already have the higher-voltage DC supply floating around inside the camera.

Re:"compared to consumer grade cameras"

[Wescotte]

I feel like this is one area they probably decided wasn't worth tackling up front as each mount probably has their own distinct requirements and challenges to get working. This is probably a task that could be best taken on by the users rather than the core developers and while most consumer level cameras/prosumer level glass might have electronic control there is still an abundance of purely manual glass and in the film work it's usually preferred.

Re: only manual lenses?

[atagunov]

Hi,

I'm not on the Apertus team however I've seen many a discussion on the IRC channel and so I can answer that. Yes indeed powered lens mounts are on the list of features. It's just that they expected after the initial release of Axiom Beta, the one which crowdfunding is being collected.

To this I would however like to add that old manual lenses are arguably rather well suited for shooting movies. I think it is an established fact of life that nearly all cinematic production is done with manual focus (google "focus puller", "first assistant camera"). Now the modern electronic lenses even if they have a manual focusing ring are not well suited for the task. The problems are:

1. the connection between the manual focusing ring and the lens part is electronic rather than mechanical - pulling focus is a lot less convenient, there is no mechanical feedback
2. focus control is not always proportionate - with a fully mechanical lens if you rotate forward 1/4 of a turn and then back 1/4 of a turn then you will arrive at the old focusing point; not so with fly-by-wire lenses - the distance your focusing point travels depends on how fast you're rotating the manual focusing ring and returning predictable to an earlier focus setting is not possible; this in particular renders useless "follow focus" devices with hard stops and pencil marks
3. it is often better if the aperture can be set in a step-less fashion

Old manual lenses certainly fix the first two issues, not sure about the last one. So I can conclude that while having a powered mount is very much desirable on Axiom cameras (and so it will come just a bit later) it is also true that the old lenses are in fact more suitable to the task of shooting movies and so the decision to deliver a fully manual Nikon-F mount first is justified

Yes I do have a nice powered lens for GH3. I also have some modern lenses my Nikon. However because of the above limitations I have already decided that should I dare to invest into actually buying an Axiom (presently I'm just a crowdfunding campaign backer) then I'll have to splash out for some old Nikkor-s as well. BTW I've been thinking of buying old glass on occasion anyway. I find it rather charming and the heavy metallic lens barrels inspire confidence in me

Re:"compared to consumer grade cameras"

[dgatwood]

I think you missed my point. If they don't provide an electrical interface near the front of the hardware as part of the core design, there's no way that users can develop any electronic mount hardware, because there's no way to communicate with said mount hardware... or at least none that doesn't involve a box fastened to the back of the camera with a wire wrapped all the way around the camera to the front.

That said, so long as they provide a multipin connector with full-voltage DC and USB pins on the interior of the body, just inside the mount, that's good enough to make it possible to add electronic mount hardware by replacing the mount with a redesigned mount. That's the minimum that the core developers must do. If they don't, first-generation hardware users will be stuck with that limitation forever, and folks will try to work around the lack of that hardware with disgusting workarounds, which future hardware users will then get stuck with... probably forever. :-)

Re:What do they mean by "Open Source"

[Wescotte]

They are releasing all the information, plans, and specs for how to purchase, manufacture, and assemble the hardware and software.

Think of it like building a PC. The vast majority of the parts standardize and readily available. However, the water cooling system doesn't mount on the motherboard so you need an adapter they designed. They released a CAD document for this adapter that lets you have it produced by any company who can machine the adapter based on the specs.

Re:"compared to consumer grade cameras"

[tigeba]

I find it more problematic that they have support micro 4:3 lenses and no support for PL mount. The lack of support for electronic lenses is really not that big a deal. The target users for these cameras don't expect or want auto aperture or autofocus. Admittedly this is a little annoying for Canon EF lenses, but anyone that gets this and is going to use non-cine lenses will probably just pick up a bunch of older full manual Nikon primes.

Re: only manual lenses?

[dgatwood]

...the connection between the manual focusing ring and the lens part is electronic rather than mechanical...

Just because a lens has electronic focus doesn't mean that it doesn't have mechanical manual focus. At least on the Canon side of things, focus-by-wire lenses are rare. Most of the focus-by-wire lenses are old, discontinued models like the 50mm f/1.0. The only current focus-by-wire lenses I'm aware of are their STM lenses (mostly low end) and the 85mm f/1.2L II. The rest of their L line is mechanical, including the 50mm f/1.2 L (popular for movie work), the 135 L II, their various zooms, etc.

The big advantage that fully manual lenses have over autofocus lenses when it comes to manual focusing is that most manual lenses have a longer throw. This makes it easier to get a more precise focus when focusing manually. They don't do that on autofocus lenses because it would make focusing slower.

With that said, I think the industry's obsession with manual focus is badly misplaced. When you're dealing with 4K video, you want the focus to be right, not just close, and autofocus is a lot more precise than any human can possibly be, even with static subjects, with the best long-throw lenses, and with a separate person doing nothing but handling the focusing. The only thing holding back autofocus for video use was the slowness of contrast-based autofocus (and its tendency to seek). With the advent of on-die phase-detect autofocus capabilities, that limitation is rapidly disappearing. Add a bit of eye tracking into the mix, and I think you'll find that within the next ten years, nobody in their right minds will still be focusing manually, particularly when they're shooting 4K.

it is often better if the aperture can be set in a step-less fashion

AFAIK, that's fairly rare even in fully mechanical lenses unless they've been modified. Perhaps dedicated cinema lenses are different in that regard. I'm not sure. But even some of my old screw-mount lenses from back in the black-and-white TV days had mechanical stops, so I'm guessing stopless lenses aren't exactly common.

So I can conclude that while having a powered mount is very much desirable on Axiom cameras (and so it will come just a bit later) it is also true that the old lenses are in fact more suitable to the task of shooting movies and so the decision to deliver a fully manual Nikon-F mount first is justified

The problem with old lenses is that they're designed for a world where cameras had relatively poor spatial resolution, and for much less reflective sensor material (film). I enjoy playing with old lenses on a 6D, and they create an interesting artistic feel, but they don't even approach the level of flare resistance, sharpness, etc. that you'd want for a digital 4K cinema camera. So if you're limiting yourself to mostly old lenses, you might as well limit yourself to 720p as well, because you'll be lucky to out-resolve that with most lenses designed more than about a decade or so back.

And if you have the money for modern, full-manual cinema lenses, chances are you aren't in the market for anything less than a highly polished, turnkey camera system.

So I really think that they need to at least lay the groundwork (in hardware) by making the plastic plates in front of the sensor removable and by including USB and DC connectors near the back side of that plate so that the system will be readily extensible in the future. That small change shouldn't require a huge amount of effort, and it will future-proof the design in a way that nothing else will.

Or, if USB isn't feasible, a high-speed serial port capable of at least 230 kbps would probably be good enough.

Just my $0.02.

Re: only manual lenses?

[dgatwood]

It will indeed be interesting to see if that happens. If I was to bet on it I would say that it's not going to happen in cinematography. Indeed moving focus through the scene is one of the tool that a cinematographer uses to achieve the desired artistic effect. It is hard to imagine that a computer algorithm would be able to predict how fast or slowly we want to bring objects in/out of focus and how much smoothness we want in these transitions.

That's an interesting question, and you're right that for that particular effect, you're probably better off doing it manually—preferably with a long-throw manual lens and a reasonably long stick attached. But that's likely to be an occasional thing, with either static focusing or traditional subject-following focusing used for probably 99% of your shots; if you're using focus to move from one subject to another for 99% of your shots, the viewers are likely to get nauseated rather quickly. :-D

Can autofocus beat the precision of a measuring tape?

Depends on how narrow the depth of field is. At large f-stops (e.g. the Zeiss 50 f/0.7 lens that Kubrick used), it can be done by hand, sure, but if you blow that up to where you can see pixels at 4K resolution, you're almost certainly going to notice the softness compared with what modern electronics could achieve, particularly if the subject is close to the lens and he or she decides to move a fraction of an inch. Mind you, that's a rather extreme case. :-) At more sane stops, it's not quite that bad. It's still a lot of work, though—work that's largely unnecessary with a decent, modern, subject-tracking AF mechanism (even without eye tracking to set the starting point). It's not that focus pulling can't be good enough, so much as that the extra work to make it good enough is significant, and it makes little sense to bother with that when a simple circuit can do at least as good a job (if not better) without all that effort. :-)

Lastly focus depth even though sometimes shallow isn't nil in most circumstances so small focusing errors might not have an adverse negative effect on the result.

That's true. With that said, the higher the resolution, the more visible that small effect becomes. At some point, you start to swear because the soft focus limits your effective resolution, and all those extra pixels are just taking up more space on disk without any real benefit. I'm not quite sure where that magic point is for manually focused movies—you'd have to ask somebody who regularly does film scanning and media ingestion for their take on it. Obviously it would depend on the f-stop, the distance to the subject, the film format, the focal length, and the skills of the person doing it. :-)

Chances are you've got the experience here while I certainly don't. However my impression so far was that what you're saying is true but not to such an extreme extent. People do use old lenses including those which are much older than a decade on modern still cameras and the results they're getting certainly don't look like they were shot with resolution of about 1/3 mega pixel provided by 720p video. I think the truth must be somewhere in between and the old glass must still be a valuable tool. After all if that glass was indeed that bad why wouldn't the prices not be nil today? Some of these lenses still command amounts of money which one on a budget would think twice before spending.

I'm probably being a bit on the cynical side; I'm sure there are some older lenses that are usable at 4K. The point I was trying to make was that the newer lenses are breathtakingly better at high resolutions—maybe not at 4K, but long before you get to 8K. And their handling of bad lighting conditions (lens flare, for example) is just amazing compared with the older lenses. Unless, o

Re: only manual lenses?

[dgatwood]

BTW, 720p is just shy of a megapixel, not a third of one. You're probably thinking of the old 720x480 format used for widescreen standard def content. :-) Not that a megapixel is all that amazing, either, mind you.

Let me correct myself further. 720p is just shy of a million full-color pixels. On a Foveon sensor, depending on how you count megapixels, that might be the same number. On a Bayer-filtered sensor, it's more in the neighborhood of 3 MP, because each color channel has about a third the spatial resolution of the sensor as a whole.