Blackmagic ZOOM & FOCUS Demands | Everything you need to know! 

A… and a mix of a and b

I come here for both A & B. So I'm of no help in this poll. But keep up the good work, it's extremely valuable information.

Jup! Both!

BOTH A & B

Both! Love the videos btw

Glad you enjoyed it :)

Most likely no, because zoom-demands have an entirely different setup compared to focus demands: focus demands usually have a grip that rotates (mechanical demands) and is basically an absolute positional device: rotating the grip rotates the lens ring via a Bowden-cable attached to the lens and the grip is thus mechanically coupled. Electronic focus demands usually have a wheel that rotates and outputs either a control voltage (older, analog style demands) and sends this to a focus-position/motor unit attached to the lens while receiving feedback (a 'follow signal' from the drive) as a PID-feedback circuit or outputs digital signals that get converted to drive-signals for the focus drive and either receives a control voltage (with potentiometer-feedback) or encoder-signals from the focus-drive (almost every lens these days) But the difference remains: even when the focus demand is as digital as can be, it's position is (basically) still coupled to the position of the lens-ring, where the zoom-demand has a seesaw/rocker that has no way of telling where the zoom-ring on the lens is: it's centered when not pushed left or right and only controls the zoom-ring when pushed to the left or right. Though I would also not be surprised if this is possible, a focus-demand just works different and when the focus puller is someone else than the camera-operator, he or she will want the classic wheel-type controller, not a seesaw-kind of control that requires far more practice in achieving the right focus position ánd lacks the possibility to mark focus-positions on the demand as professionals do when they need specific focus-points and don't have the time to pull focus but just need it to be rock-solid as soon as the operator pans/tilts or zooms to the object/subject.

I see this option for both on my 6K Pro as well.

Yeah as mentioned in the video, MFT lenses definitely have their limitations when it comes to Zoom and Focus servos… especially right now, only 4 MFT lenses have both. But hopefully we’ll see more developed in the future… as it could be a nice (cheaper) alternative to B4 :)

Well, are they really intended for B4 lenses? They were introduced with an MFT camera, and will most likely not work with B4 lenses even if you adapt a B4 to the Studio Camera, unless you find an adapter that can take signals from the MFT mount and convert to the connector used on B4 lenses? Havent seen such an adapter yet? The Ursa Broadcast G2 has a connector for B4 lenses afaik, and since the Demands work with that camera as well, sure, you can say it's made for B4.

Most lens communication on B4's is digital nowadays, so unless the Blackmagic camerahead can talk the right protocol (which I doubt, but I'm also not sure what the lens exactly returns in communication) it could possibly work. But considering Blackmagic usually rules out using other people's hardware, I would be surprised if this could work. And considering you get a USB-C connection on a Blackmagic demand (which I consider a joke, connectionwise), you're better off with a demand from Fujinon or Canon. As I'm making my own zoom and focus demand for my own 1/3 inch lenses (same idea as B4, just a smaller mount, B4 is 2/3 inch), I know that I'm either stuck with completely reverse-engineering the digital communication from the Fujinon Digi-power servo-units attached to the lens as it goes into the camera or the digital signals that can enter and exit via the dedicated zoom-demand connector on the bottom of the servo-unit, or just go with the flow and use an analog-to-digital solution: as the circuit diagrams are very clear about the connections one has to make and the signals to send and I got both focus and zoom working externally, I'm now thinking about extending the whole remote-idea by reading the zoom-follow and focus-follow signals (a feedback signal directly proportional to the position of zoom- and focusring on the lens) that comes back from the servo-unit and is inverted from the control signal), converting it to a digital value and being able to store this value on 1 or more buttons, I can have zoom and focus presets that I can recall by just the press of a button (and basically, the amount of buttons doesn't really matter, you can add as many inputs as your microcontroller features (or can be considered handy considering the available space on your remote) Ofcourse, the demands one can buy are great, but for me, as a hobbyist, they are way too costly... With all the pulled components from professional lenses I've got laying around and the focus-motors I bought cheaply off Ebay, I at least got to a point I got both focus and zoom working. Now I only need to make it into something nice ;)

​@@weeardguy hey bro im trying to figure out how can i get slow zooms, i dont care if its motorized or not, i just need it to be slow and steady, any kind of information would be appreciated

@@fgc1850 Well, that depends on the connection your B4 lens has. If it's a 'standard' (Canon and Fujinon have different pinouts) 8-pin connection on the bottom of your lens and your lens is Fujinon made, you need connection A through D and connect a zoom-seesaw to these connections (how you exactly need to wire it is something that requires some measurements and experimenting, you can hardly go wrong as long as you don't short anything). The zoom-seesaw is something I usually pull from very old standard definition lenses (try to get a hold of severely damaged units as usually the lenses are scratched or suffer from fungus, the mount is worn or the servo-unit itself sustained damage, but the zoom-seesaw hardly ever fails) If you got a 12-pin Hirose connector on the bottom (fujinon digipower), you need pins 3, 4, 5 and 7. Again, connect the zoom-seesaw to these connections. The way it works is simply that the zoom-seesaw is a potentiometer with 3 voltage connections and 1 wiper-output: Common (5V), Common-2,5 Volt, Common+2,5 Volt and your control signal (wiper) connection. The zoom-seesaw outputs 5 Volt as a control signal in the center position (which means the motor is stationary), but varies this voltage to Comm-2,5 or Comm+2,5 Volt as you depress the seesaw more in wanted direction, letting the motor turn in the wanted direction. Could you do this with a potentiometer? Oh yes, but than your potentiometer-setting will become the absolute position of your zoom as well, which means that slow-zooming than requires good control over your muscles to do that smooth and steady. The downside to this is the connector: it's expensive (the 12-pin Hirose male connector starts around 18 Euro ex VAT., close to the same in Dollars I think), the 8-in Tajimi R03-R8F3 connector is close to unobtainable. I got lucky that I could pull it from a Vinten Radamec focus-drive I bought from Ebay. Basically what you want to try is to get a hold of the manual of your B4 lens. It includes all the circuit diagrams and mentions all the signals the connectors to the outside world carry. That's how I figured out mine and though I've got the remote part figured out, making it digital (with zoom and focus presets) is another story for now... If you want you could send me an e-mail and I can send you two different circuit diagrams, as I (by now) found out that the lens-manuals are hard to find on the internet...

@@weeardguy hey thank you man, i will be looking into all of this

Hey Jayden, thats for the Zoom Demand, the focus demand can work with over 50+ lenses. Alex

@@AlexPettitt how to find out which 50+ lenses work with it?

Probably because only a few customers will buy it, secondly it's in line with competition, and finally the BG2 itself is extremely cheap.

It’s not working for me

This is very strange! If it work on the BMPCC4K, it leads me to think you may have some damage to the contact points on the MFT mount of the camera maybe.

Just for information: The Olympus M.Zuiko Digital 14-42mm works just fine without any aperture problem.

Unfortunately I didn’t have access to a speed booster to test this personally, so I can’t say

I spoke too soon - the extra burden on the USB bus means I can't record onto USB disk (rated to 2,000 mbs) at the higher setting when using the zoom demand and follow focus??? Just me?

hey man are you serious?? The zoom demand works on this lens???

Haha glad you agree :)

Totally agreed!!

Yeah I'm really hoping that these types of devices spur lens manufactures to really develop more lenses with this capability. It would be great to have a wider range!

@@AlexPettitt Especially if they have a constant aperture over the zoom range and allow the focus demand to work while zooming :)

also not constant aperture, you lose light too

Yeah the do!! Love this new update!

@@AlexPettitt @RumorsCAMERAS but the Zoom Demand is only working on the Pocket 6K, right? Or also on the Pocket 4k?

Most likely, getting a B4 mount to work on such a camera comprises reverse-engineering of software that Fujinon and Canon aren't willing to give details about, and if they do, one still has to implement it. That's the sole reason the demand probably doesn't work: don't forget that B4 lenses aren't made to work that way at all. They feature dedicated connectors for zoom-demands and (usually, not always) feature external drives to get a focus-demand going. Some lenses do have full servo-drives already installed inside the servo-unit, but my experience is that especially older lenses usually lack a focus-servo (they do have the feedback-potentiometer already installed, just not the motor to drive the ring). B4 lenses only get controlled remotely from the camera when there's a need to, but then the whole camera gets connected via a dedicated connection that controls everything (zoom, focus, iris, ND, extender (if any), white-balance and all other things that control the image. Then, the lens is controlled via a serial connection over the same connection that usually only connects to the camera for power, feedback of iris, focus and zoom settings. If the original manufacturer does not want to give information on the communication used, you're just out of luck and basic support is what you get at most.

I know exactly what you mean! Fingers crossed more lenses with this functionality will be announced in the near future :)

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