How Exposure Impacts Low Light Video Surveillance

By: IPVM Team, Published on Dec 07, 2009

Exposure, and the tricks manufacturers play with exposure, are key to accurately and fairly assessing low light performance of cameras.

For instance, take these two images:

The images capture the same scene but look substantially different. However, which one is better?

No doubt, the image of the right (Camera B) is much brighter and the vehicle in the background is much easier to see. However, these two images are from the same camera - simply with a change to the maximum exposure setting.

Keep in mind that:

  • Using still images as 'proof' of video surveillance quality can easily be used to mislead
  • The 'hidden' problem is that long exposure times blur moving objects to the point of being unusable.

To be clear, the answer in our poll above has to be Option C.  Not enough information can be determined from a still image.  It is not a fair assessment to say that Camera B is a superior product because of it's image quality. In fact, both images are from the exact same camera.  The key differentiator between the two shots is that they were captured at different exposure settings - the 'dark' Camera A at 1/30s and the 'bright' Camera B at 1 second. 

Exposure Sample Videos

Download the sample video clips that demonstrate a moving subject  [56 MBs] with the exposure configurations at 1/60 s, 1/30 s, 1/15 s, 1/8 s, 1/2 s, and 1 s.  This should give you a starting point to determine for yourself what trade off between discernible subjects and motion blur is acceptable for your security application.

Exposure Comparison

Get Notified of Video Surveillance Breaking News
Get Notified of Video Surveillance Breaking News

View the screencast to see the actual video clips compared under different exposure configurations. Note that the subject on the 1 second exposure setting is distorted by a significant amount of motion blur.  Is the subject running or walking? If the subject ran fast enough, he would look like a ghost across the screen: that is not an acceptable configuration for monitoring people.

Camera Exposure Settings

In this screencast, we examine the issues and process of adjusting maximum exposure time settings in 5 cameras. 

  • The defaults for maximum exposure time varies by camera. The Axis Q175, Stardot and Sanyo have 1/30s default for maximum exposure. The Basler has 1s default for maximum exposure (though they report planning to change this to 1/8s in a future release). The Pelco has 1/30s max during day mode operation and 1/8s during night mode. Going from 1/30s to 1s is a 30x difference in the amount of light captured - a significant variance that will have dramatic performance impact.
  • These settings generally can only be changed from the camera's web interface as VMS generally do not support adjusting these settings in their administration tools. 
  • The naming, location and options for each camera's maximum exposure time settings vary. For instance, Axis and Basler provide options in a range of fractional seconds while Sanyo's options are a multiple relative to the capture rate. See the video below for more details.

 

Risk of "Sleight of Hand" Marketing

Referring back to the poll question example images, it is a trend for some manufacturers to market their camera's night time quality in this fashion. It is important that you factor in the specific settings used to capture the video. 

Recommendations

Providing users options for maximum exposure time is a good thing. Marketing great image quality through the use of very long exposure times is a dangerous practice, specifically because of manufacturer's omitting to disclose the problems with motion blur.

Here are our recommendations for maximum exposure time settings:

  • For applications requiring a strict 30fps, then the maximum exposure should be no more than 1/30s. Otherwise, the longer exposure makes it impossible to generate a unique image for each frame. That being said, for night time, low light viewing, 30fps is likely to be unnecessary.
  • For moving people (running or walking), 1/8s maximum exposure setting should be fine to eliminate motion blur and provide usable images throughout the entire video. While many manufacturers set their maximum at 1/30s, we believe that 1/8s will significantly increase visible details (because of more light) while not introducing new defects.
  • For moving vehicles, more than 1/8s and perhaps up to 1/30s maximum exposure settings may be needed (this, of course, depends on the speed of the vehicles). 
  • If you are willing to sacrifice images of moving objects with the understanding that when they stop you should capture a clear image, than 1/2s or 1s maximum exposure time makes sense. However, this tradeoff needs to be clearly appreciated by the users prior to commissioning the system.

10 reports cite this report:

New Surveillance Products Directory Fall 2011 on Sep 21, 2011
This report provides a summary of key announcements and news being made related to or around the ASIS 2011 show.For each product or change, where...
New Surveillance Products Review June 2011 on Jun 14, 2011
In this report, we provide in depth coverage of new surveillance product releases announced in May and June 2011. Below are the products we are...
Axis Lightfinder / Q1602 Examined on May 24, 2011
In this note, we examine the features, competitive positioning and pricing of the Axis Q1602. This camera's announcement has generated a...
Overviewing Absolutron's Megapixel Cameras on Nov 28, 2010
In this note, we overview Absolutron, a startup megapixel camera manufacturer based in California, USA. The company specializes in high frame rate...
Video Surveillance RFPs Reviewed - Vol 1 on Nov 08, 2010
In this report, we review 4 recent real-world video surveillance Request for Proposals (RFPs). RFPs provide a good look into the needs, challenges...
How Critical Should We Be of Video Surveillance Products? on Feb 07, 2010
IP Video Market Info is definitely critical of video surveillance products - routinely looking for hidden problems or over-hyped claims. Many love...
Examining Basler's Market Acceptance on Feb 01, 2010
Recently, SecurityInfoWatch ran a 'fluff' piece on Basler, regurgitating their marketing claims with no analysis. Key claims made: The small...
Testing Axis's Q1755 HD Surveillance Camera v. 2 on Jan 04, 2010
This report shares extensive test results, video clips and training screencasts on the Axis Q1755 HD camera. The goal is to educate on how the...
Normalize Exposure Settings for IP Camera Comparisons on Dec 22, 2009
We recommend all surveillance camera comparisons be performed with normalized exposure settings to ensure fairness and eliminate 'games'. Starting...
Guidelines for Testing IP Cameras on May 25, 2009
What is the best way to test an IP cameras? We have established guidelines for our tests. These guidelines are listed below for your review and...

Related Reports on Low Light

Panasonic 4K Camera Tested (WV-S2570L) on Sep 13, 2019
Panasonic has released their latest generation 4K dome, the WV-S2570L, claiming "Extreme image quality allows evidence to be captured even under...
WDR Camera Mega Shootout 2019 - Avigilon, Axis, Bosch, Dahua, Hanwha, Hikvision, Panasonic, Vivotek on Sep 04, 2019
This is the biggest WDR Shootout ever, with 23 cameras from 8 manufacturers: We included true multi-exposure WDR and non-WDR models, ranging...
Uniview 4K Camera Tested on Aug 29, 2019
In our 8MP / 4K Fixed Lens Camera Shootout, Uniview's low end 8MP was firmly in the middle of the pack. Does their higher end Pro Series 4K camera...
Wyze Image Quality Tested vs Axis, Hikvision And Nest on Aug 27, 2019
With Wyze's new AI feature, it is strong at analytics, but how good is the camera's image quality? Is it just as good as incumbents like Axis,...
Anyvision Facial Recognition Tested on Aug 21, 2019
Anyvision is aiming for $1 billion in revenue by 2022, backed by $74 million in funding. But does their performance live up to the hype they have...
Dahua 4K Camera Shootout on Aug 20, 2019
Dahua's new Pro Series 4K N85CL5Z claims to "deliver superior images in all lighting and environmental conditions", but how does this compare to...
Axis 4K Camera Shootout 2019 on Aug 14, 2019
Axis' 4K Q3518-LVE claims the "best video quality possible", with Lightfinder super low light performance, Axis' high end Forensic WDR, and...
Hikvision 4K Camera Shootout on Aug 02, 2019
With their latest Smart Series 5 cameras, Hikvision is claiming cameras "fully loaded" with "state-of-the-art technology for high performance and...
Hanwha 4K Wisenet P Camera Tested on Jul 30, 2019
Hanwha claims "premium performance" and to "deliver the best in high resolution performance and efficiency" with their Wisenet P series 4K models,...
Bosch Starlight 8000i Cameras Tested on Jul 23, 2019
Bosch has released their new Flexidome IP Starlight 8000i cameras, claiming "exceptional detail even in extreme low-light situations." To see...

Most Recent Industry Reports

US Army Base To Buy Banned Honeywell Surveillance on Sep 17, 2019
The U.S. Army's Fort Gordon, home to their Cyber Center of Excellence, has issued a solicitation to purchase Honeywell products that are US...
Vivotek "Neural Network-Powered Detection Engine" Analytics Tested on Sep 17, 2019
Vivotek has released "a neural network-powered detection engine", named Smart Motion Detection, claiming that "swaying vegetation, vehicles passing...
Schmode is Back, Aims To Turn Boulder AI Into Giant on Sep 16, 2019
One of the most influential and controversial executives in the past decade is back. Bryan Schmode ascended and drove the hypergrowth of Avigilon...
Manufacturers Unhappy With Weak ASIS GSX 2019 And 2020 Shift on Sep 16, 2019
Manufacturers were generally unhappy with ASIS GSX, both for weak 2019 booth traffic and a scheduling shift for the 2020 show, according to a new...
How Cobalt Robotics May Disrupt Security on Sep 13, 2019
While security robots have largely become a joke over the last few years, one organization, Cobalt Robotics, has raised $50+ million from top US...
Panasonic 4K Camera Tested (WV-S2570L) on Sep 13, 2019
Panasonic has released their latest generation 4K dome, the WV-S2570L, claiming "Extreme image quality allows evidence to be captured even under...
ASIS GSX 2019 Final Show Report on Sep 12, 2019
IPVM went to Chicago for ASIS GSX 2019, with many exhibitors disappointed about traffic and the exhibitor schedule changing next year. However,...
Installation Course - Last Chance - Register Now on Sep 12, 2019
Last Chance - Register Now - September 2019 Video Surveillance Install Course. Thursday, September 12th is your last chance to register for the...
Commend ID5 Intercom Tested on Sep 12, 2019
Commend touts the new ID5 intercom as 'timelessly elegant' and the slim body, glass front touchscreen indeed looks better than common, but ugly,...
US State Department: "Chinese Tech Giants" "Tools of the Chinese Communist Party" on Sep 12, 2019
The US State Department has called out "Chinese tech giants" for being "tools of the Chinese Communist Party" in a blunt new speech that makes...