- Monitoring for aesthetics
- Monitoring for technical validity or merit
Rule of thumb: A good external monitor, or display, should be capable of both.
To judge aesthetics, one looks at the image, namely the colors, the framing, the focus, and hopefully the performance.
To judge technical merits, one looks at data from the image, reinterpreted as waveforms, graphics or other information. This information is critical to keeping the video within the boundaries of the agreed-upon standard for delivery.
How do you judge a shoe at a shoe store? First you look at what excites you. Then you might want to see if it fits you, and whether its material, stitching, etc., will work with your lifestyle. Video is no different.
Sometimes the video just looks wrong. With experience, you’ll come to understand the quirks of your system and will know the exact setting to change to fix the problem. But when you’re using a new system, a good understanding of monitoring a video technically will help you fix it faster. Or you could just flip switches in trial and error mode, while everyone else waits.
The goal of your external monitor is to show you exactly what you’re shooting. If it distorts the signal (or ‘jazzes’ it up, as consumer grade or cheap monitors tend to do) for some reason, then you might want to reconsider what you’re monitoring.
Your monitor must ideally:
- Have the same resolution, frame rate and aspect ratio as your video feed
- Have compatible connectors and standards
- Have a separate battery/power supply
- Be visible in sunlight
- Be rugged and, most important
- Be ‘better’ than the in-built camera LCD/LED display
In what respects can the external monitor be ‘better’ than the in-camera display? The most immediate difference is one of size.
How to find the right size monitor
What is the ideal size of an external monitor? 5″, 7″, 9″, 15″, 24″ or more? Some productions are able to afford more than one monitor, so everyone’s happy. Most productions though, can’t afford or don’t need more than one.
Here’s my system of arriving at the right size:
It’s not rocket science. I’m not going to explain it in detail because most of it is already covered in Driving Miss Digital. But here are few notes:
- The maximum size I find practical on a rig is 14″. And even that’s pushing it.
- The reason why there’s a maximum size is that once you go over this, the perceptible resolution decreases.
- When more than one person is viewing a monitor, they won’t always be at the same distance from it.
- The tendency of most individuals is to always approach the monitor to be as close as possible, just like moths.
- Even though director/client egos might demand the biggest screen possible, the resolution will not support it at close distances.
With this system, I’m no longer bogged down by display size. And now, you needn’t be, either.
The next thing you’ll need to look for is whether the signal standard, connector and specifications match. This is where the preceding chapter will be of assistance.
Rule of thumb: If the monitor cannot display the feed as is, it is useless, in my opinion.
Once you’re guaranteed an accurate signal, you can now begin to look for tools that will help you manipulate it:
- Internal Calibration
- Color Space/LUTs/Profiles
- Color Gamut
- Bit Depth
The sky’s the limit. With RAW files, you might have two additional steps before the signal is ready: De-comprsession (Redcode) and De-bayering. This ‘ready’ signal will have to be passed through a LUT for correct display.
Theoretically, a monitor can be designed with rigid standards baked in. Won’t that make things simpler, you might be wondering. No. Why? Because what looks like good color to one might look like too much to another. What might appear sharp to one will appear fuzzy to another. So whose eye will the monitor be designed for?
Rule of thumb: A good monitor should provide enough controls to please your eye.
The next important consideration is the signal standard. E.g., the most common standard you’ll find today is the SMPTE 292M standard, as follows:
- 10 bit 4:2:2
- Maximum 1920x1080p30 at 1.485 Gbps
- Interlaced or Progressive (psF masked as interlaced)
- Rec. 709 color space (ITU-R Recommendation BT.709)
- 4 channel audio at 24-bit 48KHz
- Both video and audio can be compressed or uncompressed
This standard is delivered via an HD-SDI BNC connector, as we have seen earlier. The monitor must be capable of understanding this signal without adding its own juice. Sometimes, cheap monitors and recorders add their own juice to fill up things they are not designed to understand (somewhat like how frog DNA was inserted between dino DNA in Jurassic Park).
Rule of thumb: If you are unable to find information on whether a monitor is fully compatible with the signal delivered by the camera, assume it does not match.
Before I move on to suggestions, here’s my personal take:
When it comes to data inspection, I’ve observed one curious peculiarity: The eyes don’t lie. If it looks good on a big bright broadcast monitor you are okay.
Rule of thumb: Usually the numbers should match what you see visually. When in doubt between data and vision, always rely on your eyes.
Unless your audience is an army of data wranglers or signal processing engineers.
Ask any DP who has shot on film prior to the digital revolution.
How did they judge exposure?
How come they were so certain?
How did they realize their vision on celluloid?
Did they use calibrated monitors on set, with 10-bit displays and LUTs?
Why is it that with all this technology on set many DPs still can’t make great images consistently?
Rule of thumb: If you know your camera, lighting and lens inside out, you don’t need an external monitor.
I find its effect more therapeutic than essential. Seeing your image in its final form is a relief. Only you can tell whether you need an external monitor or not.
Rule of thumb: If you still don’t know, even after having read this chapter, whether or not you need an external monitor, you don’t need one.