HDMI and External Monitors

A dancer crosses the stage and you follow her with the camera on a gimbal, a motorised handle that keeps it steady, held at hip height. The Z6III's own screen is 3.2 inches corner to corner (p. 1000), an arm's length away and seen at a slant. Is her face sharp? Is the spotlight burning out her white sleeve? At that size and angle you are guessing.

Put a 7-inch screen where your eyes already are and the guessing stops. The link is an HDMI cable. This chapter traces its signal and every setting Nikon gives you for it, then covers the NEEWER F700 monitor I use, the cable and the mounting. USB streaming, the camera's other video output, closes the concepts.

01.What an HDMI Cable Carries

HDMI, short for High-Definition Multimedia Interface, is the connection a television uses to take a picture from a set-top box. The Z6III has the full-size socket, called Type A (pp. 48, 1006), on its left side, as A Tour of the Body shows. One cable carries the picture, the sound, and short control messages running both ways.

The Picture, Uncompressed

A video file on the card is compressed, as Video Formats and Codecs explains. HDMI is not. Every frame goes down the cable whole, so an external recorder, a separate box that saves the HDMI picture to its own storage, receives it before compression touches it.

HDMI describes colour as YCbCr, a brightness number Y plus two colour-difference numbers, Cb and Cr, that neighbouring pixels may share, and Video Formats and Codecs explains the 4:2:2 and 4:2:0 sharing patterns and the 8-bit and 10-bit depths quoted here.

Now count. A 4K frame is 3840 by 2160 pixels, so it holds $3840 \times 2160 = 8{,}294{,}400$ pixels. In 4:2:2, two pixels carry four numbers, two values of Y plus one Cb and one Cr, which averages two numbers per pixel. At 10 bits each that is 20 bits per pixel, so one frame is

$$8{,}294{,}400 \times 20 = 165{,}888{,}000 \text{ bits.}$$

At 30p, roughly 30 frames a second, that becomes about 4,977 megabits per second for the picture alone. Nikon puts an H.265 10-bit (MOV) file of the same size and rate at about 190 megabits per second (p. 207). Since $4{,}977 \div 190 \approx 26$, the cable carries roughly 26 times the data the file keeps.

What the Z6III Puts on the Wire

The sampling and bit depth on the cable depend on the Video file type you record and on its Frame size/frame rate (pp. 307-308).

Two rows deserve a second look. The H.265 10-bit (MOV) file itself is 4:2:0 (p. 198), yet at 4K 30p the cable carries 4:2:2. A 4:2:0 picture holds half a colour number per pixel and a 4:2:2 picture holds one, so a recorder receives twice the colour detail the camera's own file stores. The other surprise is the drop to 4:2:0 at 4K 120p and 100p, for which Nikon gives no reason. A 10-bit signal reaches only a device that accepts 10 bits (p. 308), and 2160/120p or 2160/100p needs an input built to the HDMI 2.1 standard (p. 302).

The tone mode chosen inside Video file type shapes the cable too (p. 308). SDR, standard dynamic range, is ordinary video that any screen shows correctly. N-Log, Nikon's logarithmic recording, arrives flat and grey. HLG, Hybrid Log Gamma, is a high dynamic range format that needs a screen built for HLG (pp. 215, 308). N-Log, HLG and Exposure Tools explains each. The stage setup records SDR, so the monitor needs no correction.

Slow-motion footage reaches a recorder at real speed (p. 204), and the X button's magnified view reaches the HDMI picture only with a RAW type, between takes (p. 306).

Sound and Control Signals

Sound shares the cable. On a television the audio plays through the television, at a volume set there (p. 302).

The control messages turn HDMI into a conversation. Under Auto output resolution the camera learns which sizes and rates the device accepts before choosing one (p. 304). In HLG, a device that announces HLG support gets a "gamma: HLG" label back (p. 215). A compatible recorder can be started and stopped from the camera (p. 308), can receive timecode (p. 617) and, on some Atomos models, file names, a firmware 2.00 addition listed in Firmware History. Timecode, the hours, minutes, seconds and frames label on each frame, belongs to Audio and Timecode, though one warning matters here: Nikon says On (with HDMI output) under Record timecodes may disrupt the HDMI picture (p. 617).

Why a Bigger Screen Helps on a Gimbal

A three-axis gimbal has one motor for each way the camera can turn, so it holds steady while your arms move. Its best shots put the camera low, high or out in front, where its screen faces you at an angle, from a distance, or both. A 7-inch screen against 3.2 inches is a diagonal ratio of $7 \div 3.2 \approx 2.2$, and for screens of the same shape the area grows with its square, $2.2^2 \approx 4.8$, a rough figure because the two panels need not share a shape. Mounted on the handle, it keeps facing you whatever the camera does.

02.USB Streaming, the Other Video Output

The camera's second live output is its USB-C socket, with the camera acting as a webcam. Firmware 2.00 added it (Firmware and Updating), and the switch is in the network menu.

The default is MTP/PTP, for moving files (p. 871). Choose USB streaming (UVC/UAC), connect a computer or phone with the supplied USB cable, and the camera waits in standby until a streaming or calling app starts the stream (pp. 219-220). UVC and UAC are the USB Video Class and USB Audio Class, the standard webcam and USB microphone descriptions that calling software already understands.

The output is modest next to HDMI. Video is MJPEG, Motion JPEG, in which each frame is compressed on its own as a JPEG picture, at 1080 or 720 lines and at 60p or 30p, whichever the device and app ask for. Sound is PCM, pulse-code modulation, meaning plain uncompressed samples, 16-bit and stereo (p. 220). The stream uses the video-mode display and the video menu's choices, white balance among them, even with the selector at photo (p. 219).

Streaming shuts a lot out. While it runs the camera cannot record video, zoom its display, use HDMI, connect to software such as NX Studio, or run time-lapse, focus shift or auto capture, and opening a menu turns the stream grey. It ends if USB is changed, the cable comes out or the camera is switched off (p. 220). Install the app first. Some devices also need an extra connection program, and Nikon does not promise that every device will work (p. 220).

03.The HDMI Item

The setup menu's HDMI item holds four sub-items, whose defaults Nikon lists on p. 806. Two more settings that affect HDMI, External rec. cntrl (HDMI) and the Timecode item's Record timecodes, sit in the video recording menu (pp. 617, 619).

Output Resolution

Output resolution sets the size of the picture on the cable: Auto, the default (p. 806), 2160p (progressive), 1080p (progressive), 1080i (interlaced) or 720p (progressive) (p. 303). The number counts picture lines. Progressive sends each frame complete. Interlaced sends it as two half-pictures, odd lines then even, an older broadcast method, at 60i or 50i (p. 306). Auto never picks it (p. 304).

Under Auto the camera first offers the size and rate you are recording, with 5376 by 3024 sent as 2160 and the 240p and 200p modes as 1080/120p and 1080/100p. If the device declines, the camera works down a fixed list, trying 1080 at the same rate and then lower rates, and stops output if nothing is accepted (pp. 304-305). With a card in the camera, 4K 120p and 100p skip the 4K steps and start at 1080/60p or 1080/50p (p. 305).

A fixed choice sends that size or nothing. Output stops if the choice is larger than the frame being recorded or the device cannot take it, and a refused rate steps down, 120p to 60p to 30p (pp. 305-306). With cards in, 2160p (progressive) sends nothing at 4K 120p or 100p, and Nikon's remedy is to remove the cards and record to the recorder alone (p. 306). The RAW types cap the output at 1920 by 1080 whatever you choose (pp. 214, 305).

NEEWER lists 1080p at rates up to 60, 29.97 among them, and 3840 by 2160 only at 30, 25 and 24 Hz for the F700, with no 2160 at 60 and no 1080 at 120. The gap at 29.97 matters, because the camera's 30p is really 29.97 frames a second (pp. 201-202). Neither maker says whether the F700 reports those limits to the camera the way a recorder does, and the table below assumes it does.

I set 1080p (progressive). The F700's panel has 1080 lines, so 4K would be scaled down anyway. At 60p or slower the fixed choice stays inside NEEWER's 1080p list, and at 120p it still relies on the camera stepping the rate down to 60p (p. 306). It never exceeds the frame being recorded, since the camera records nothing smaller than 1920 by 1080. It also moves a quarter of the data: at 4:2:2 10-bit, 1080/30p is $1920 \times 1080 \times 20 \times 30 \approx 1.24$ billion bits per second against 4.98 billion for 2160/30p. A reader recording 4K externally wants Auto or 2160p (progressive) instead, so the recording keeps every pixel.

Output Range

Output range decides which numbers stand for black and white. The default is Auto, which matches the device and is Nikon's recommendation (pp. 303, 806). In full range an 8-bit signal uses every value, 0 for black to 255 for white. In limited range, the broadcast convention, black sits at 16 and white at 235, leaving $235 - 16 + 1 = 220$ levels.

A mismatch shows in the shadows. Send full range to a screen expecting limited and everything at 16 or below shows as black, merging 17 shades into one: that calls for Limited range. Send limited range to a screen expecting full and black arrives at 16, shown as dark grey, so the picture looks washed out: that calls for Full range (p. 303). Otherwise leave Auto alone.

Output Shooting Info

Output shooting info decides whether the camera's icons are drawn over the HDMI picture. The default is ON (p. 806), and a recorder then stores those icons in the footage (p. 303), so a recorder user chooses OFF.

For a monitor it is taste, and mine is OFF, so the F700 shows only the picture. Neither maker addresses this, but a monitor cannot tell an icon from a pixel of the scene, so the icons would likely count in its histogram and false colour.

Mirror Camera Info Display

Mirror camera info display decides whether the camera's own monitor stays lit while HDMI is connected. The default is ON (p. 806). OFF leaves it dark to spare the battery, but Nikon locks the item at ON whenever Output shooting info is OFF (p. 303). That suits the gimbal setup in Viewfinder and Monitor Displays: the camera's monitor swung out, showing brightness information and the red recording frame.

04.Recording to an External Recorder

A recorder has its own screen and its own encoder, so it, not the camera, compresses what it stores. I do not own one, so this section is for a reader who does. With a card in the camera each take goes to both card and recorder, and with no card only the recorder keeps it (p. 303).

External Rec. Cntrl (HDMI)

With ON, the camera's controls also start and stop the recorder. The default is OFF (p. 579). Whether a recorder obeys is for its maker to confirm, and the camera's icon shows only what it asked for, so watch the recorder's own display (p. 308).

Two cautions come with it. ON may disturb the HDMI picture (p. 308), and the troubleshooting pages name it as one reason video may display badly (p. 919). And the standby timer in Custom Setting c3, 30 s by default (pp. 624, 661), switches the display off when it runs out, and HDMI output stops with it. For external takes Nikon's advice is No limit, or any setting that outlasts your longest take (p. 308). Nikon raises this for recorders, but since the timer ends all HDMI output, I expect a monitor to go dark between takes too. In theatres my c3 is already at No limit, set for silence in Silent Shooting, Timers and Time-Lapse, so there the timer never cuts the F700. Its battery cost belongs to the batteries and power part of this guide.

RAW Video and a Recorder

Raw video, recorded as N-RAW or as ProRes RAW, is sensor data not yet made into a finished picture, and the Reference Guide describes no way to send it down the cable. With a RAW type selected the HDMI picture is an ordinary 4:2:2 10-bit image, no larger than 1920 by 1080 and 8-bit in playback (pp. 214, 305, 307). I do not record raw video myself.

05.The NEEWER F700

My field monitor is NEEWER's F700, and every figure here is NEEWER's, from its product page, not a measurement of mine. NEEWER lists a 7-inch touch screen of 1920 by 1080 pixels at 16:9, rated at 2,000 nits plus or minus 10%, which it calls actual measured brightness. A nit, one candela per square metre, is the usual unit of screen brightness. NEEWER also lists 1000:1 contrast, a viewing angle above 160 degrees both ways, an HDMI input, an HDMI output it calls a 4K loop, and a 3.5 mm headphone jack.

Power comes from NP-F batteries, a 12 to 26 V DC input, or USB-C at 5 V and 3 A. NEEWER rates the two included NP-F750 batteries at 2.4 hours each, 4.8 together, and lists the weight as 445 g bare, 654 g with one battery and 857 g with two.

Three gaps matter. NEEWER does not say whether the F700 accepts 10 bits, which HDMI version it implements, or which standard its HDR mode follows. It calls the monitor's colour the "Rec.709 HD color standard", Rec. 709 being the standard for ordinary HD video, so whether it shows HLG correctly is unknown. The loop output lets a reader pass the signal on to a recorder, but neither maker says whether recorder control and timecode survive that extra hop, so ask both before relying on it.

Monitor-Side LUTs

A LUT, or look-up table, remaps each colour the monitor receives to a new one, and a 3D LUT remaps red, green and blue together, built as N-Log, HLG and Exposure Tools explains.

NEEWER lists 15 preloaded 3D LUTs and room for up to 60 more from an SD card. A LUT changes only what the panel shows, never the camera's file, so N-Log can be watched as a normal picture. Nikon offers N-Log LUTs on its Download Center that convert to Rec. 709 (p. 216), but whether that file loads on the F700 is a question for NEEWER. The camera's own View assist does a similar job, covered in N-Log, HLG and Exposure Tools. Recording SDR, I load no LUT.

Exposure Tools on the Monitor

NEEWER lists these tools: "False Color, Zebras, Histogram, Oscillogram, Full Waveform, Vectorscope, HDR, Single Color, Peak Focus, Audio Bar". False colour repaints the picture by brightness, each band in a fixed colour, so a glance shows what is near clipping and what is near black. NEEWER's page does not print the colour scale, so learn it before trusting it. A vectorscope plots each pixel at an angle set by its hue and a distance set by its saturation, so a colour cast shows as a lopsided cloud. Peak Focus appears to be NEEWER's name for focus peaking, which outlines sharp edges in colour.

06.Cables and Strain Relief

Nikon expects a third-party Type A cable whose other end matches the device, and asks you to switch the camera off before plugging in or unplugging (p. 301). My F700 runs from a coiled full-size cable.

A coil is a spring. The further it stretches, the harder it pulls, and that pull lands on the plug in the camera's socket. On a gimbal that pull changes as the camera tilts and rolls, so the motors must fight it. That is my reasoning, not something Nikon or DJI documents, and it leads to one rule: the plug should carry no load.

Nikon supplies a cable clip for this (p. 35). It screws into a hole beside the sockets (p. 48), HDMI cables use its other channel, and it may not fit every cable (p. 975). Nikon also says to keep the monitor in its storage position while the clip is fitted (p. 975), which rules out the swung-out screen of the gimbal setup. Nikon gives no reason. The monitor hinges on the socket side, so my reading is that the open screen and the clip collide.

On the gimbal I would leave the clip off and take the strain at the rig. Fasten the cable to something rigid that moves with the camera, such as the camera plate, leaving a small slack loop before the plug, so the coil pulls on the plate. Keep it slack through the full tilt and roll. With the 3 Legged Thing Zadie L-bracket fitted, open both connector covers first, as A Tour of the Body describes.

07.Mounting a Monitor on the Gimbal

DJI rates the RS 5's tested payload at 3.0 kg. Payload is the load the gimbal carries on its plates: camera, lens and anything fixed to them. The Z6III weighs about 760 g with battery and card (p. 1008). Add the F700 with one battery and the camera end reaches $760 + 654 = 1{,}414$ g, 47% of the rating before any lens. With two batteries it is $760 + 857 = 1{,}617$ g, or 54%. Perched high and to one side, the monitor also shifts the balance point.

So the monitor belongs on a part of the gimbal that does not move with the camera, where it costs the motors nothing. DJI's specification page lists RSA/NATO ports, a 1/4"-20 mounting hole and a cold shoe on the RS 5 but does not say where each sits, so check before choosing one. NEEWER lists 1/4" screw holes on the F700, a cold shoe mount that turns through 180 degrees, and a monitor mount in the box.

Your arms pay instead. DJI lists the gimbal at about 1,193 g with its quick-release plates and the grip at about 274 g. With the camera and the monitor on one battery, $1{,}193 + 274 + 760 + 654 = 2{,}881$ g, nearly 2.9 kg before the lens, which is worth knowing before a long recital. How the camera's stabilisation behaves on a gimbal is in Video Autofocus and Stabilisation.

08.Recommended Settings

A reader with a 4K recorder keeps Output shooting info at OFF so no icons reach the file, sets Output resolution to Auto or 2160p (progressive), and turns External rec. cntrl (HDMI) to ON if the recorder supports it, with the standby timer set past the longest take.

09.Beginner Mistakes

Plugging in with the camera on. Nikon asks you to switch off before connecting or disconnecting the cable (p. 301).

Expecting 4K 120p on the cable with a card in. With 2160p (progressive) and cards inserted, 4K 120p and 100p send nothing (p. 306). Use Auto, which falls back to 1080, or record to the recorder alone.

Letting the standby timer cut the feed. When the c3 standby timer runs out, HDMI output ends (p. 308). For external recording set it past your longest take or to No limit.

Recording the camera's icons. With Output shooting info at its default ON, a recorder stores the icons in the footage (p. 303).

Blaming the camera for a blank screen. Check the cable first (p. 918), then the output resolution against what the device accepts (pp. 304-306), the standby timer (p. 308) and USB streaming, which shuts HDMI off (p. 220).

10.Related Chapters

• A Tour of the Body: the sockets, the clip hole and the covers.
• Viewfinder and Monitor Displays: the camera's own screen on the gimbal.
• Video Formats and Codecs: the file types and tone modes behind the signal.
• N-Log, HLG and Exposure Tools: View assist, zebras and the waveform.
• Audio and Timecode: the camera's sound settings, the microphone route, and the Timecode item, whose On (with HDMI output) passes timecode to a recorder.
• Video Autofocus and Stabilisation: the camera's stabilisation on the RS 5.
• Firmware and Updating: firmware 2.00, which added USB streaming.
• Firmware History: file names sent to some Atomos recorders.