Introduction
The Rolling Shutter Calculator estimates the amount of image skew (in pixels and degrees) caused by rolling shutter artifacts based on your camera's sensor readout time and the speed of subject movement in the frame. Rolling shutter occurs because CMOS sensors read the image line by line from top to bottom rather than capturing the entire frame simultaneously. Fast-moving subjects or rapid camera pans cause the image to appear tilted or wobbling. This calculator helps you predict whether rolling shutter will be a visible problem for specific shots before you commit to a camera system or shooting technique.
What This Tool Calculates
Nearly all digital cinema cameras use CMOS sensors with some degree of rolling shutter. The severity varies dramatically between cameras. An ARRI Alexa has a readout time of approximately 12ms, while some mirrorless cameras exceed 25ms. At 12ms, rolling shutter is rarely visible in normal shooting. At 25ms, fast pans and action sequences can produce distracting skew and wobble. Knowing your camera's readout time and understanding at what subject speeds rolling shutter becomes visible helps you choose the right camera for the job and plan your shooting techniques accordingly.
The Formula and How It Works
Skew in pixels equals the subject velocity in pixels per second multiplied by the sensor readout time in seconds. If a subject crosses the full frame width (4096 pixels) in 0.5 seconds, its velocity is 8192 pixels per second. With a 15ms readout time, the skew is 8192 x 0.015 = approximately 123 pixels. This means the bottom of the subject will be displaced 123 pixels from where the top was captured. The angular skew in degrees can be calculated from this pixel displacement relative to the frame height.
Real-World Examples
How to Use This Calculator
Enter your camera's sensor readout time in milliseconds. This information is available from camera reviews and manufacturer specifications. Enter the subject speed across the frame. You can express this as the time it takes for a subject to cross the full frame, or as a physical speed if you know the distance to subject. The calculator shows the expected pixel displacement, angular skew, and a severity rating indicating whether the distortion will be negligible, noticeable, or problematic for professional output.
Tips from Working Professionals
| Detail | Value |
|---|---|
| Camera assistants and DITs recommend testing for rolling shutter artifacts during camera prep by recording fast pan shots and reviewing the footage frame by frame. | |
| If rolling shutter is a concern for your project, avoid whip pans, reduce handheld camera movement, and use wider lenses (which show less skew because subjects move across more of the frame at lower apparent speed). | |
| Post-production stabilization can sometimes worsen rolling shutter artifacts, so stabilize conservatively if your footage has any existing skew.. |
Pro Tips and Common Mistakes
Pro Tips
- Cinematographers evaluating camera choices for action-heavy projects, VFX supervisors planning green screen and motion capture work (where rolling shutter creates compositing problems), and sports and event videographers working with fast-moving subjects..
Common Mistakes
- Do global shutter cameras eliminate this problem? Yes.
- Global shutter cameras like the ARRI Alexa 35 and Sony VENICE 2 (in certain modes) capture the entire frame simultaneously, producing zero rolling shutter skew.
- Can rolling shutter be fixed in post? Partially.
Frequently Asked Questions
What is an acceptable readout time for cinema work?
Under 15ms is generally acceptable. Under 10ms is excellent. Over 20ms may cause visible issues with fast action.
Does frame rate affect rolling shutter?
Frame rate does not change the readout time, but higher frame rates reduce motion blur, which can make rolling shutter artifacts more visible.
Start Calculating
Most camera specification sheets list readout time but do not contextualize what that number means for actual shooting. This tool translates readout time into practical pixel displacement values for specific subject speeds, giving you actionable information rather than abstract numbers.
