Crash Course on External Recording Monitors

Crash Course on External Recording Monitors

External recording monitors are the Swiss Army knives of the camera department. They are an external hard drive, a reference monitor, and an exposure assist tool all in one device! They are used at all levels of production, from one (wo)man crews to big budget commercials and movies.

When You Need an External Recording Monitor

In order to determine whether or not you will need an external recording monitor for your camera, it’s very important to understand what your post-production needs will be. Most modern digital cameras on the market, at every price point, can produce quality images on their own. So if you have a project with a fast turnaround and without the necessity of color work, you may not need an external monitor solution. However, if you plan on doing moderate-to-heavy color grading or green screen work, the more color information and less compression the better. You’ll want to pay attention to the quality of the codec that the camera produces as well as the color space.

Less Compression and Better Codecs When Using External Recording Monitors

One feature that all recording monitors share is the low-compression codec, Apple ProRes. Despite what the name may imply, ProRes codecs are fully compatible with Macs as well as PCs and can be used with most non-linear editing systems. These codecs are capable of high data rates and color space, which is a major reason why they come standard in external recording monitors. The most common formats of ProRes that you’ll find (listed in descending quality) are: ProRes 422HQ, ProRes 422, and ProRes LT.

External Recording Monitors and Color Space Benefits

Many entry-level prosumer cameras like the Panasonic GH4 or the Sony a6500 record highly-compressed 4:2:0 color subsampling internally, which means that in order to save on bandwidth most of the color information is thrown away. This can be circumvented by using an external recorder like the Sound Devices Pix-E7, which is able to accept a 4:2:2 signal (up to 4K resolution) from those cameras, allowing you to retain more color information. This is not to say that footage with 4:2:0 color space will necessarily look inferior to footage with a 4:2:2 color space. You’ll notice the subtle difference in quality if you zoom in on areas of the image where you see a sharp transition between two colors, especially if they’re contrasting colors. Pixels along the edge of a color transition in a 4:2:0 colorspace image will look muddy due to the high level of color subsampling. However, the loss of color information in a 4:2:0 image is more apparent when you start pushing colors around while color grading or when you’re trying to perform a chroma key for green screen work.

4:2:0 Left, 4:2:2 Right

Zoomed In – 4:2:0 Left, 4:2:2 Right

If heavy color or special effects work is involved and it is within your budget, you’ll want to strive for the most color information possible with ideally no color subsampling. Top-of-the line cameras like the ARRI Alexa Mini and even the budget-friendly Blackmagic Ursa Mini 4.6K have the ability to record in 4:4:4 color space, which means that every pixel’s color is represented and, therefore, no subsampling has occurred. The Odyssey 7Q can to take a RAW signal from select cameras and encode it into enormous, data-rich codecs, ProRes 4444XQ, and ProRes 4444. The Odyssey 7Q, Atomos Shogun, and Shogun Flame also allow you to record RAW to CinemaDNG without compressing the data into a ProRes Codec. As you can imagine, this allows for even further control over the manipulation of the footage. These files can be astronomically large so be sure to gauge your data storage and computing power before considering recording RAW or ProRes 4444.

Using the External Recording Monitor as Your Backup Recorder

Aside from color and compression, you can use an external recording monitor to record continuously, beyond the DSLR or mirrorless camera’s manufacturer-imposed recording time limit. Another reason you may want an external recording monitor is if your camera records massive, data rich files and you want to record more compressed files to accompany your camera’s internally-recorded footage. This reduces stress on your computer during editing. Once you’ve finished your edit, you can replace the proxy footage with the master files. Additionally, you can use an external recording monitor to record backup footage at the same time you are recording on your camera.

Choosing the Right Recording Monitor for Your Needs

Identify whether your camera is capable of outputting a clean video signal via an HDMI or an SDI port. Most modern digital cameras have at least an HDMI port and are able to output a clean video signal. You may find that older cameras and a small number of budget-friendly cameras are only able to output a cropped video feed along with embedded camera information. Higher-end cinema cameras will also have an SDI port in addition to an HDMI port. In most cases, the SDI port will be the superior connection in that it will be capable of transferring larger amounts of data at the speed required for real-time monitoring and recording. Some cameras that are equipped with an SDI port are even able to output a RAW signal. At the moment, even the fastest HDMI ports are not capable of transferring the massive amount of data involved with RAW video.

The Panasonic Varicam LT can output a RAW signal via an SDI port.

Once you find out which ports your camera is able to output a video feed from, be sure to choose a monitor that is capable of matching that connection. For example, aside from lacking SDI inputs and outputs as well as RAW recording capabilities, the Atomos Ninja Flame has all of the functionality of the higher-end Atomos Shogun Inferno, so it’s a budget-friendly pairing if your camera only has an HDMI port.

Choosing the Correct Media for your Recorder

It’s important to research the compatible storage devices as well as the speed requirements of the recorder you’ll be using. The Odyssey 7Q and the Atomos series recorders all technically use SSDs with the 2.5″ form factor. However, you’ll notice that only certain brands and speeds are acceptable depending on the model. Despite the fact that the Blackmagic Video Assist 4K takes SD cards, which is a common storage device, the list of compatible SD cards is, in fact, very limited. If the storage device does not fall within the exact parameters of recommended media for your recording monitor, you will risk skipped frames, disrupted recording or merely the inability to record at all.

Communicating with the External Monitor

Once you have your recorder connected to the camera and your media is freshly formatted, one of the last things to do is to set your recording settings. The first step is to ensure that the camera is sending a clean feed to the recorder. As I’ve mentioned earlier in the article, some older cameras and a small number of budget DSLRs will only output a compressed feed. However, some cameras that are capable of sending a clean HDMI feed will actually output a compressed feed as part of their factory default settings. HDMI settings can be easily accessed via the menu.

Example of Sony a7S HDMI menu options.

Choosing the Resolution and Framerate for Your Recording

Most cameras that can shoot 4K typically have the ability to output 4K as well as 1080p and, in certain models, 2K. Take care to identify if the camera is capable of outputting 4K and simultaneously record internally at the same resolution, if simultaneous recording is possible at all. It’s important to note that external recording monitors typically mirror the incoming signal’s resolution and framerates and are typically only adjustable via the camera. The Odyssey 7Q is an exception in that you have the ability to down-convert 4K to 2K or 1080p.

Record Triggers and Signal Transfers

Most external recording monitors have the ability to be triggered to record via the camera’s record button as long as the camera is capable of that feature. When your camera is set to trigger record mode and you hit the record button on the camera, a digital signal is sent to the recorder, called a “flag”. The signal transfer is instant and triggers the external recording monitor to record. A flag can be sent via HDMI or SDI depending on the camera.

A recurring theme you may have gathered from this article is the importance of doing your homework! There are a large number of cameras and a variety of external recording monitors out in the world. Some combinations will work and others may surprisingly not. Nothing is worse than receiving a camera package shortly before a shoot and realizing that your recording monitor can’t record the framerate that you need or your media is incompatible. Borrowlenses has a knowledgeable team of video specialists who will be more than happy to help you navigate through the confusing process of choosing the right monitor.

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Mike Sun is a Video VIP Quality Control Technician Lead at BorrowLenses and a freelance cinematographer and photographer.

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