If you’re looking to upgrade your livestream, and you’ve already dialed in your audio and lighting, the next step is image quality. It is the third leg that holds up the broadcast stool, and image quality is partly based on one thing in particular—your camera sensor. Now, to really nail it, you’ll need a good lens, too, but a nice lens into a small sensor will reduce image clarity and sharpness just as much as a “meh” lens on a big sensor. If you’re going to make the jump, it’s not a bad idea to start shopping for cameras based in part on the size of the sensor.
Sounds a little complicated, but the sensor in your camera does what film used to do, just via digital means…
But first, what are camera sensors and why do they matter?
Well we’ve talked about this on here before, but here’s the quick rundown: digital cameras capture light on a sensor. Before the advent of digital cameras, your shutter opened and captured light on a piece of film and so your film was your sensor. The big breakthrough for digital cameras was developing technology that allows light to be captured and interpolated into digital data, and, instead of film, we call that little device a “sensor.” Here’s an explanation from Cambridge in Colour:
“A digital camera uses an array of millions of tiny light cavities or "photosites" to record an image. When you press your camera's shutter button and the exposure begins, each of these is uncovered to collect photons and store those as an electrical signal. Once the exposure finishes, the camera closes each of these photosites, and then tries to assess how many photons fell into each cavity by measuring the strength of the electrical signal. The signals are then quantified as digital values, with a precision that is determined by the bit depth. The resulting precision may then be reduced again depending on which file format is being recorded (0 - 255 for an 8-bit JPEG file).”
Sounds a little complicated, but the gist is the sensor in your camera does what film used to do, just via digital means. As such, camera sensors are built more or less to mimic the sizes of traditional film, although some manufacturers make sensors that stray from those common sizes.
So, if you’re wondering why the image of that show you’re watching looks so much more crisp than your livestream, in part that’s due to the sensor on professional cinema cameras. A larger sensor creates a more detailed image and allows the camera to perform better in low light settings because the photosites themselves are larger, thus capturing more light. Most camcorders and smaller cameras utilize a micro four-thirds (4/3) sensor, which you can see in the following image is much smaller than the full frame sensor commonly used on most cinema cameras. Many manufacturers of smaller cameras or camcorders utilize 4/3 sensors because they offer a balance of image quality to compactness; essentially, you get a pretty good image in a small package that they can fit into a small camera.
But times are changing, and full frame sensors in small cameras are more available and affordable partly thanks to the advent of mirrorless technology, which, without going into too much detail, allows a big sensor to fit in a smaller chassis because there’s no mirror reflecting an image up to the viewfinder. What you see on your viewfinder is what your sensor is seeing.
If my camera has a high megapixel count, I should get really detailed images, right? Well… no, actually.
A Note About Megapixels
If my camera has a high megapixel count, I should get really detailed images, right? Well… no, actually. Your megapixel count directly correlates to the size of the photosites on your sensor. If you have a high megapixel count on a smaller sensor, the sensor has crammed a lot of little photosites together, so, even though it seems like you’re capturing a lot of data, the image will lack clarity and contain more noise in low-light images. The same megapixel count on a larger sensor results in a higher-quality image because the photocells are larger, so each pixel itself has more data. Small sensor = small photosites = tiny pixels and vice versa.
So, what sensors are a good idea for your budget?
Full Frame
This sensor approximates the size of 35mm film, the standard in many cinema cameras. It’s been out of reach for most of us until recently, but manufacturers are making it approachable because demand is rising. Sony, Nikon, and Canon all make camera bodies with a full frame sensor around or under $2000. Blackmagic Design offers a particularly good value with the Pocket Cinema 6k at just under $1600.
The drawback is that you’ll need to find a lens as well, which can get pricey quick. However, a lens is a lens, and there’s plenty of used or refurbished lenses floating around on the internet that can work for tighter budgets.
APS-C
The next step down from full frame, APS-C offers a sweet spot for cost savings with image quality in mind. Major manufacturers offer various models ranging from $1700 down to near $500. Again, you’ll need a lens, but this sensor format is popular, so there’s a lot of lenses out there that fit these cameras. You’re going to get a more detailed image than your standard camcorder or point-and-shoot, but you won’t pay as much as you’d need to for a full-frame camera.
Micro 4/3
This is the classic value sensor, and every manufacturer uses it to add value for their customer base. You’ll find cameras with these sensors that offer a lot of bells and whistles because of the cost savings associated with the smaller sensor. To be clear—it’s not a bad sensor just because it’s smaller. It’s a nearly perfect trade-off for image quality and expense, which is why it’s so popular. If you need the best bang for buck, don’t be afraid of cameras with a micro 4/3 sensor.
Further Reading
Church Production contributor Ryan Geeseman wrote a great article earlier this year that offers more of a deep dive into camera sensors and how they affect shots, so please read that if you’d like to learn more about them. The above linked Cambridge in Colour article is nerdier for those of you that really want to understand the science of camera sensors.
