Hdmi: Powering Cameras Or Just For Data Transfer?

HDMI technology has become the global standard for connecting HD equipment, transmitting digital video and audio signals through a cable. It supports video signals including 1080p, 1440p, and 4K, as well as multi-channel surround audio. While HDMI is essential for connecting audio systems to a TV, it is also useful for cameras, especially when shooting video. However, a common question arises: can HDMI be used to charge cameras?

HDMI output in cameras is useful for streaming video to a separate monitor

HDMI output in cameras can be useful for streaming video to a separate monitor. This is particularly handy in small studio settings, where the camera operator does not need to move around too much. The monitor or TV can stay in a central area, while the camera moves around. This setup is also useful for streaming a meeting, conference, or show to another room at an event.

HDMI technology transmits digital video and audio signals through a cable. The video signals supported include 1080p and even beyond that (1440p and 4K). The audio signals include multi-channel surround audio. All of the signals are transferred 100% digitally, which is a big improvement over the previous technology that HDMI replaced. This technology has set the standard globally for connecting HD equipment.

When deciding on a camera for streaming, it is important to consider whether it has a clean HDMI output. A clean HDMI output is a video feed that doesn't contain any camera icons, setting graphics, or data indicators displayed over the video itself. It's a live signal straight from the camera sensor, through an HDMI connection, to its intended destination. Dirty or not-clean HDMI outputs, on the other hand, have graphics baked into the video feed that cannot be removed after filming.

Some cameras that are known to have clean HDMI output include the Sony Alpha 7 III, Canon EOS R, and Panasonic Lumix S5. The Canon EOS 80D is another camera that can output to HDMI and has impressive video capabilities, although it does not support 4K video recording.

HDMI cables carry 5V of power

HDMI cables are one of the most common connectors for video and audio interfaces. They can carry digital video and audio signals, but they are not designed to deliver power. While they do carry power, it is not enough to power devices like external displays, monitors, TVs, or PCs. The maximum voltage for HDMI is 5 volts, and the maximum current it can carry is 50 mA over just one pin, which is intended to deliver power to connected devices. This amounts to only 0.25W of power, which is insufficient to power most multimedia devices.

The primary goal of the HDMI interface is not to power or charge devices, which is why external displays have separate power sources. A typical PC monitor requires 25-60 watts of power, while even the lightest multimedia devices, such as Chromecast, require 1-2 watts. As a result, almost all HDMI interface devices require an external power source.

The latest version of HDMI, HDMI 2.1a, includes a new feature called HDMI Cable Power. This feature allows supported devices to be connected without needing a separate power cable. However, since it supplies 5V @ 300mA, or 1.5W, it is still not sufficient to power most everyday devices.

HDMI power delivery can be used for small devices such as HDMI switches, splitters, and converters, as well as small single-board computers like the Raspberry Pi. It is important to note that using a non-standard cable or adapter could potentially damage devices or create a safety hazard. Additionally, powering high-wattage devices like laptops or desktop computers could overload the cable or port, leading to damage or safety issues.

HDMI can be used to charge a laptop

Firstly, you will need to check that your laptop has an HDMI-IN port. Most laptops have an HDMI-OUT port, which is used for transmitting audio and video signals but is not intended for charging. If your laptop has an HDMI-IN port, you can connect it to the HDMI-OUT port of a charging device, such as a TV, monitor, DVD player, or Blu-ray player.

If your laptop does not have an HDMI-IN port, you will need an adapter. Modern laptops with USB-C ports can use an HDMI-to-USB-C adapter, while other laptops may require an HDMI-to-Type C or Type B adapter. Apple laptops, in particular, often require this type of adapter due to their limited number of ports.

It is important to note that charging a laptop via HDMI is extremely slow. The power from an HDMI port is typically 5v, while most laptop chargers provide 18-20v. Using this method for an extended period can damage your laptop, and there is a risk of short-circuiting if you connect to the wrong port. Additionally, HDMI ports do not have the same safety features as standard charging cables, so there is a risk of overcharging if you leave your laptop plugged in.

Overall, while it is technically possible to charge a laptop via HDMI in certain situations, it is not recommended due to the slow charging speed and potential risks to your device.

USB-C ports can be used to charge cameras

USB 3.1 Type-C cables offer a transfer rate of 10 GBps, which is twice as fast as the transfer speed of USB 3.0 (5 GBps). This speed can be achieved when both the camera and the computer have USB-C data ports. For example, when shooting tethered with a Nikon Z7 and a new MacBook Pro (both with USB-C ports), images will transfer twice as fast as with a camera and computer using USB-A.

Some cameras with built-in USB-C charging include the Fujifilm XT-3, Canon EOS R, Phase One XF IQ4, and Nikon Z7. The Sony A6600 also charges via USB-C, although it does so slowly. The Panasonic Lumix GX9 is another camera with USB charging, although it uses a micro-USB connection rather than USB-C.

USB-C is electrically compatible with older USB 3.0 ports, but adapters or cables with appropriate plugs are required due to the shape of the newer port.

HDMI output is useful for viewing scenes on a separate monitor

HDMI output is incredibly useful for viewing scenes on a separate monitor. This is especially handy when shooting video, as it allows you to see what you're filming on a larger screen, which can be positioned wherever you like. This is a great solution if the digital screen on your camera is too small or inaccessible.

To do this, you'll need a camera with an HDMI output, an HDMI cable, and a monitor or TV with an HDMI input. Simply hook up the HDMI output on your camera to the HDMI input on the monitor or TV, and you've created an extension of your camera. This setup gives you the flexibility to position the viewing screen however and wherever you like, which is very convenient in small studio settings.

If your computer has two HDMI outputs and both your monitors have HDMI inputs, you can use standard HDMI cables to set up dual monitors. However, if your computer has different video outputs, such as HDMI and DisplayPort or DVI, you may need an adapter cable. An HDMI splitter can also be used to connect multiple monitors to a single HDMI port.

It's worth noting that when using an HDMI splitter, both monitors will display the same content, and you won't be able to extend your desktop across them. If you want a true dual-monitor setup with different content on each screen, consider using a docking station, which adds extra ports to your computer.

Additionally, when connecting two monitors to a computer with one HDMI port, you can use wireless alternatives like a wireless display adapter or DisplayPort Multi-Stream Transport (MST) technology. Wireless display adapters allow your PC to connect wirelessly, while MST hubs support multiple HDMI monitors through a single DisplayPort connection.

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