Oh FFS. He's shooting with electronic shutter under stadium lights and the banding is from that. https://t.co/ghLCCac9xK
— byron@bikehugger (@bikehugger) June 27, 2017
Recently, t-shirt salesman, camera reviewer, YouTuber Jared “Fro Knows Photo” Polin took to Instagram, Twitter, Facebook and his own site, to declare that his Sony a9 has a “banding problem.”
The a9 doesn’t, and we’ll get to that in a second, but first I think it’s important to address the YouTube phenomenon of racking up viewership by proclaiming a major and fatal flaw in some piece of gear and claiming “first” on bringing that fatal issue to the attention of the public. The best products to take-down in a video are the most popular or most eagerly anticipated. If you remember the iPhone “bendgate” scandal you’ll be familiar with this.
The procedure here is to take a product, find either a flaw or more likely a perceived flaw and rush out a video with a sensationalist headline. For all the “bendgate” stories about the iPhone, I never met a person that had their phone bend.
Sometimes though, the “flaw” isn’t a flaw at all, it’s a lack of understanding of how the technology works, and that’s the case with the most recent “banding” video from “Fro” about the Sony a9. As a refresher, the Sony a9 operates primarily in electronic shutter mode, an operation where instead of a physical, mechanical shutter ending each frame, the camera controls the shutter duration by powering on and off the imaging sensor.
If the sensor has power, it’s capturing data, if it’s off, it doesn’t capture anything. This is what enables the Sony a9 to reach 20fps speeds, and the way that electronic shutters work with certain artificial light is what’s causing this “banding” that Fro has experienced. There’s no “issue” with the Sony a9, aside from Fro not knowing how the technology he’s holding works.
When we look at light from the sun, it’s always on. There’s a constant stream of photons coming from the sun (this is a simplification, as the intensity and amount are constantly changing, but let’s stick with this as a baseline) and so if we take a photo under sunlight, all the parts of the sensor will receive the same intensity of light at the same time.
Unlike sunlight, artificial light is non-constant. Fluorescent bulbs, LEDs, tungsten lights all pulse on and off with the flow of electricity through them. (This is also a simplification, but let’s keep going.) A tungsten light flickers, but the pulse of the current is fast enough that the filament hasn’t really stopped glowing by the time the next pulse of electricity hits it, so it produces a more flicker-free light.
Other light sources have various frequencies of the on/off pulse. Most of them flicker faster than the human eye can detect, but there is generally flicker in any light source. If your lights are at 120hz, then they are turning on and off 120 times a second, if they are 60hz, they turn on and off 60 times a second.
In other words, it is some degree darker for some fraction of a time per second than in another fraction of a second. With a mechanical shutter, the whole sensor is on when the shutter goes up, and it’s still on when the shutter goes down. This makes a mechanical shutter camera less prone to the effects of flicker because the whole sensor is exposed at once. An electronic shutter (at least a progressively read electronic shutter) reads lines of information from the sensor from top to bottom or from side to side. Because it’s reading while the light is flickering, it’s possible for the sensor to record that flicker, and the result is banding.
Think of it like this—a sensor is made up of 10 rows from top to bottom. When you press the shutter release, the camera reads each row, one at a time, from 1 to 10. When row 1 is being read, the light source is pulsing on, but by the time the camera is reading row 2, the light has pulsed off, and so on. That means that every row will be relatively darker or lighter than the next, and that’s banding.
This phenomenon is very widely known and is a huge consideration in the cinema world, where the electronic shutter is the norm. Many high-end cine cameras have built-in anti-flicker settings to detect and reduce this, and on any movie set, the flicker rate of the lights is measured so that the camera can be set to a shutter speed that’s a multiple of that flicker rate. If your lights flicker at 30hz, you can shoot at 1/30, 1/60 or 1/120th of a second and not get flicker.
To return to the problem with Fro’s “the sky is falling” video, the “banding” problem isn’t a problem. It’s a tradeoff of using an electronic shutter. When operating under some artificial light sources, the flicker of the light will be recorded as stripes of differing exposure lines, which he called banding.
Fro was shooting the a9 in a soccer stadium, where all types of artificial lights are present, from the stadium lights themselves to the signs displaying the score. The banding that he’s encountered is caused by the flicker rate of the artificial light.
With a new technology, there’s nothing wrong with being confused. What is wrong is blaming the camera gear without talking to an expert. As a member of the photo trade press, Fro has access to product managers. It would have been a simple matter to call someone and ask them about this issue before posting a video blaming a camera for his lack of technique.
This isn’t good for Fro’s reputation, and it’s not good for the camera industry in general, and it’s not good for Sony in particular. These posts don’t vanish. Because of conversations (like those on Twitter and this one here) about this issue, Google will associate a9 and “banding” even though there’s no banding.
The problem with the clickbait nature of YouTube is that it rewards sensationalism over the fact (that’s a pretty good parallel to many things going on these days) and that sensationalism can really do harm. I’m sure some people decided not to buy a Sony a9 based on this “issue.”
Products have flaws and tradeoffs, that’s just part of life. A good journalist takes a look at those, weighs them, and checks their facts before giving their “expert” opinion. Beware though any headline that proclaims a product is flawed or a product is perfect—it’s not possible for either to be completely true.