How Exposure Impacts Low Light Video Surveillance

Author: 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 Video Surveillance News In Your Inbox
Get Video Surveillance News In Your Inbox

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

May 2018 Camera Course on Apr 20, 2018
Save $50 on early registration until this Thursday, the 26th. Register now (save $50) for the Spring 2018 Camera Course This is the only...
Axis Launches First Stereographic Panoramic Camera on Apr 05, 2018
Fisheye panoramics have not had much innovation in the past few years, with their multi-imager cousins getting most of the advances, e.g.,...
Dahua 4K Micro 4/3 Camera Tested (IPC-HF8835F) on Apr 03, 2018
Dahua is going big. Their new 4K HF8835F Micro Four Thirds sensor is one of the largest now on the market. Dahua is claming: Starlight...
Axis Z-Wave IP Camera Tested Poorly on Mar 20, 2018
Z-Wave is drawing notable interest for video surveillance use. In IPVM's initial coverage, 84% expressed interest in it, with nearly half being...
Camera Form Factor Guide on Mar 16, 2018
When selecting surveillance cameras, users may choose from a number of different form factors, each with its own unique strengths and weaknesses,...
Next Gen 5MP / 6MP Camera Shootout (Axis vs Dahua vs Hanwha vs Hikvision) on Feb 28, 2018
Many manufacturers have released new generation 5MP / 6MP cameras that tout super low light, WDR and other features historically typical in 1080p...
Hikvision 6MP Camera Tested (DS-2CD4565-IZH) on Feb 27, 2018
In the next installment of our ongoing testing of 5MP/6MP cameras, we test the Hikvision DS-2CD4565F-IZH, a 'Smart Series' vandal dome combining...
Hanwha Wisenet X 5MP Camera Tested (XNV-8080R) on Feb 13, 2018
Wisenet X is Hanwha's high-end camera line. We tested their Wisenet X 1080p camera last year. Now Hanwha is offering 5MP cameras listing super low...
Axis 'Best' Q3517-LVE 5MP Camera Tested on Feb 05, 2018
Axis boasts of its Q3517-LVE: Simply put, AXIS Q3517-LVE delivers the best video quality possible. But is it really the 'best'? We bought...
Dahua 5MP Starlight Camera Tested (N52BM3Z) on Jan 30, 2018
Is 5MP the new 1080p? According to our recent statistics, average resolution continues to trend upwards. And now, manufacturers releasing new...

Most Recent Industry Reports

May 2018 Camera Course on Apr 20, 2018
Save $50 on early registration until this Thursday, the 26th. Register now (save $50) for the Spring 2018 Camera Course This is the only...
Global Real-Time Video Surveillance - EarthNow on Apr 20, 2018
A new company, EarthNow, with backing from Bill Gates, Airbus and more, is claiming that: Users will be able to see places on Earth with a delay...
Dedicated Vs Converged Access Control Networks (Statistics) on Apr 20, 2018
Running one's access control system on a converged network, with one's computers and phones, can save money. On the other hand, hand, doing so can...
April 2018 IP Networking Course on Apr 19, 2018
This is the last chance to register for our IP Networking course. Register now. NEW - 2 sessions per class, 'day' and 'night' to give you double...
Rare Video Surveillance Fundraising - Verkada $15 Million on Apr 19, 2018
Fundraising in video surveillance (and the broader physical security market) has been poor recently. Highlights are few and far in between...
'Best In Show' Fails on Apr 19, 2018
ISC West's "Best In Show" has failed. For more than a decade, it has become increasingly irrelevant as the selections exhibit a cartoon level...
Security Camera Cleaning Frequency Statistics on Apr 18, 2018
150+ integrators told IPVM how often they clean cameras on customer's sites and why.  Inside we examine their answers and break down feedback...
Worst Access Control 2018 on Apr 18, 2018
Three access control providers stood out as providing the most problems for integrators. In this report, we analyze the answers to: "In the...
Axis VMD4 Analytics Tested on Apr 17, 2018
Axis is now on its 4th generation of video motion detection (VMD), which Axis calls "a free video analytics application." In this generation, Axis...
Arecont CEO And President Resign on Apr 17, 2018
This is good news for Arecont. Arecont's problems have been well known for years (e.g., most recently Worst Camera Manufacturers 2018 and starting...

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