What is rolling shutter, and how does it affect the image of the camera?
The rolling shutter effect is also called the jello effect, which in short is the result of the sensor's pixels not being read simultaneously. Most often you can see the rolling shutter when shooting moving objects (or from a moving object, like a car) where lines are distorted, as shown in the image above.
This is the case with most CMOS sensors as they read the sensor output line by line, resulting in a type of wobbly feel to a moving image.
Only on CMOS Sensors
The Rolling Shutter effect is only present in cameras with CMOS sensors, due to the readout method used in those sensor types. When shooting on a camera with a CCD sensor instead of a CMOS sensor, the entire image is saved out as a whole for each recorded frame.
This means that the CCD image does not get skewed like that on a CMOS sensor, and that it feels more like the traditional way of capturing moving images; capturing it on analog film, one entire frame at a time.
Does that mean CCD is better than CMOS?
Well, no. While the CCD sensors are great at what they do — capturing the entire frame at once — they have other drawbacks which are often regarded as "worse" than the rolling shutter of CMOS, such as:
- lower resolution
- vertical flaring when filming bright lights
- more power hungry
- less sensitive to light (requiring more gain/higher ISO values)
This is why the CMOS sensors have become so popular over the last decade, despite their flaws like rolling shutter or fixed pattern noise.
CMOS Cameras Without Rolling Shutter
There are some CMOS sensors that actually do not have rolling shutter. Some of these cameras are:
Frequently Asked Questions
Below are the answers to a few of the most frequently asked questions regarding the rolling shutter effect.
1. Do all CMOS cameras have rolling shutter?
No, all cameras with CMOS sensors do not suffer from a rolling shutter.
2. Can I remove the Rolling Shutter effect in post?
Yes, there are multiple tools available for removing rolling shutter in post. For example, Adobe Premiere features a Remove Rolling Shutter plugin that can be used — however this is time consuming and does cause some artifacting.