Shutter Speed / Exposure Tutorial

Author: John Honovich, Published on Nov 28, 2016

Surveillance users do not need to be photography experts but understanding the basics of shutter speed is critical to avoiding major low light problems. In low light conditions, surveillance video can appear blurry and objects will look like ghosts - all due to issues with exposure.

Here is an example:

In this tutorial, we explain the role of exposure and setting shutter speed has in surveillance including a 5 minute video screencast to show you the key issues in action.

Shutter Speed / Exposure

The terms shutter speed and exposure are often used interchangeably but are technically not the same thing.

Shutter speed refers to how long the sensor is exposed to light. Exposure consists of shutter speed ('how long') combined with iris opening ('how wide') but is often simply used to mean shutter speed, leading to confusion. As a practical matter, most surveillance cameras either have a fixed iris or the iris will automatically become as wide as possible in low light, leaving shutter speed as the key parameter to adjust.

In this tutorial, we focus on shutter speed. For details on iris and aperture, see our Lens Iris Tutorial and F-Stop Tutorial.

Automatic Vs. Manual Shutter Speed

Surveillance cameras almost universally default to automatic control of the shutter speed, meaning that the camera will continue to adjust its speed without any intervention of the user. In brighter scenes, shutter speed will be faster (e.g., 1/1000s), but if it is quite dark, the shutter speed slows (e.g., 1/30s).

Get Video Surveillance News In Your Inbox
Get Video Surveillance News In Your Inbox

Users typically may set minimum and maximum shutter speeds to better control how widely the camera may vary its exposure. However, this is not normally required unless issues are visible or manufacturers use poor defaults (such as slow shutter / sens-up, covered later in this post).

Now, nearly all cameras use automatic shutter speed, but manual settings are still used in some specialist applications such as license plate capture / recognition and machine vision.

Range of Shutter Speeds

Shutter speeds can range from extremely fast (1/1,000, 1/10,000 of a second or less) to extremely slow (1/2 of a second or more). Under normal circumstances, since shutter speeds are controlled automatically, fast shutter speeds rarely have negative effects.

However, when using even a slightly slow shutter speed (such as 1/15 second), motion blur may be significant, obscuring details. The threshold where blur occurs varies widely, depending on light level, object speed, and other variables, with no hard and fast rule for what is universally "too slow."

Recommend 1/30s Minimum Shutter

That being said, we strongly recommend against using shutter speeds slower than 1/30s in almost all cases, as blur is likely even on slow moving objects. For faster moving objects (e.g., cars), minimum shutter speeds of 1/60s or higher may be needed to eliminate blur, depending on the speed of the vehicle.

Exposure in Action

Watch the 5-minute video below for a demonstration of different shutter speeds and dealing with slow shutter settings.

Fixed Shutter Speed

IP cameras most often allow advanced controls for fixing the shutter speed of a camera. However, we do not recommend this except in very specific applications.

The most common surveillance application for fixed shutter speed is license plate capture. The images below show the same camera in a license plate capture application, using default 1/30s shutter speed and 1/500s shutter. Using defaults, even at slow speeds (<10 Mph) the camera is unable to capture the plate, while at 1/500s, the plate is clearly legible.

Manufacturer Tricks

Now, most manufacturers allow their cameras to automatically adjust shutter to as slow as 1/30s by default. However, users beware: some manufacturers still default to slower shutters which may cause significant blur in low light even on slow moving objects. See our Camera Slow Shutter / Ghosting Test for details.

Additionally, manufacturers may use other techniques which essentially amount to slow shutter in practical use, such as Sens Up, "Intensifier", or frame integration. Users should beware of these terms, and when in doubt, disable these features to see how performance changes.

Other Blur Issues

Users should also beware of other features in IP cameras which may also cause blur. High levels of digital noise reduction (DNR) used in today's super low light cameras may introduce blur. Additionally, true wide dynamic cameras may introduce blur, as well, as they combine multiple exposures to generate the WDR image, with small movements between. These issues may appear very similar to shutter blur, but they all have different causes. Because of this, technicians may need to adjust several settings to remove blur for best results.

1 report cite this report:

Avigilon Real Time Exposure And Gain on Feb 24, 2015
Knowing how exposure and gain impact image quality, bandwidth, and camera performance can useful in installation and troubleshooting. Very few...
Comments : PRO Members only. Login. or Join.

Related Reports

IP Camera Cable Labeling Guide on Sep 14, 2018
Labeling cables can save a lot of money and headaches. While it is easy to overlook, taking time to label runs during installation significantly...
October 2018 Camera Course on Sep 13, 2018
Today is the last day to save $50 on the October 2018 Camera Course, register now. This is the only independent surveillance camera course,...
Drain Wire For Access Control Reader Tutorial on Sep 04, 2018
An easy-to-miss cabling specification plays a key role in access control, yet it is commonly ignored. The drain wire offers protection for readers...
Exit Devices For Access Control Tutorial on Aug 28, 2018
Exit Devices, also called 'Panic Bars' or 'Crash Bars' are required by safety codes the world over, and become integral parts of electronic access...
Inputs/Outputs For Video Surveillance Guide on Aug 24, 2018
While many cameras have Input/Output (I/O) ports, few are actually used and most designers do not even consider them. However, a good understanding...
Backup Power for Large Security Systems Tutorial on Aug 24, 2018
Choosing the right backup power system depends on system size. While small and medium systems greatly benefit from using UPS battery backup...
Axis First IR PTZ Tested (Q6125-LE) on Aug 21, 2018
Axis is very late in releasing IR PTZs. While competitors such as Hikvision and Dahua have offered them for years, Axis has just released their...
Backboxes for Video Surveillance Tutorial on Aug 15, 2018
Backboxes are a necessity in surveillance, whether for managing cable whips, recessing cameras, adding wireless radios. But it can be confusing to...
Camera Focusing Tutorial on Aug 09, 2018
A camera's focus is fundamental to quality imaging. Mistakes can cause important problems. In this guide, we explain focus issues and proper...
Hikvision PanoVu Mini Tested (Multi-imager + PTZ For ~$500) on Aug 07, 2018
Hikvision has released their first PanoVu Mini multi imager, the PanoVu DS-2PT3326IZ-DE3, with four 1080p imagers, including a PTZ and integrated...

Most Recent Industry Reports

25% China Tariffs Finalized For 2019, 10% Start Now, Includes Select Video Surveillance on Sep 18, 2018
A surprise move: In July, when the most recent tariff round was first announced, the tariffs were only scheduled for 10%. However, now, the US...
Central Stations Face Off Against NFPA On Fire Monitoring on Sep 18, 2018
Central stations are facing off against the NFPA over what they call anti-competitive language in NFPA 72, the standard that covers fire alarms....
Hikvision USA Starts Layoffs on Sep 18, 2018
Hikvision USA has started layoffs, just weeks after the US government ban was passed into law. Inside this note, we examine: The important...
Chinese Government Praises Hikvision Following Xi Jinping on Sep 17, 2018
The Chinese government council responsible for managing China's state-owned companies praised Hikvision’s obedience to China’s authoritarian leader...
Amazon Ring Spotlight Cam Tested on Sep 17, 2018
Amazon's Ring has released their latest camera entry, the Spotlight Cam, which we bought and tested in our Consumer IP Camera Analytics...
European Mega Security Firm Verisure Pushing Security Fog on Sep 17, 2018
The European mega security firm Verisure (Securitas Direct), with a reported 2 million customers, is pushing security fog, as shown in this BBC...
IP Camera Cable Labeling Guide on Sep 14, 2018
Labeling cables can save a lot of money and headaches. While it is easy to overlook, taking time to label runs during installation significantly...
Favorite Intercom Manufacturers 2018 on Sep 14, 2018
Intercoms are certainly increasing in popularity, driven by the integration of video and IP networking. But who is the favorite? On the one side,...
Vivotek 4MP Camera Tested (FD8379-HV) on Sep 13, 2018
Next in our series of updated 4MP testing, we bought and tested Vivotek's FD8379-HV, and entry level 4MP model claiming "top-notch quality video in...
Ascent / MONI Faces Lender Lawsuit and Debt Crisis on Sep 13, 2018
ASCMA, aka Ascent, aka Brinks Home Security, aka MONI, aka Monitronics is being sued by a group of their lenders who allege: As of June 30,...

The world's leading video surveillance information source, IPVM provides the best reporting, testing and training for 10,000+ members globally. Dedicated to independent and objective information, we uniquely refuse any and all advertisements, sponsorship and consulting from manufacturers.

About | FAQ | Contact