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 on Low Light

Covert IP Camera Shootout - Axis, Hanwha, Hikvision, March, Vivotek on Mar 20, 2019
Covert cameras were one of the last holdout areas for analog cameras. However, in the past few years, IP / HD covert cameras have become...
Axis IR Multi Imager Camera Tested (P3717-PLE) on Feb 18, 2019
Axis has released their first IR multi imager, the P3717-PLE, a repositionable model listing 360° IR illumination and flexible positioning,...
Hanwha Smaller Multi Imager Tested (PNM-9000VQ) on Feb 14, 2019
Hanwha's first repositionable multi imager PNM-9081VQ tested well, but was huge, over 12" wide and weighing in at over 10 pounds. Now, they have...
Bandwidth vs Low Light Shootout - Avigilon, Axis, Bosch, Dahua, Geovision, Hanwha, Hikvision, Uniview, Vivotek on Feb 08, 2019
Nighttime bandwidth spikes are a major concern in video surveillance, but do all manufacturers' cameras perform the same? Are some more consistent...
Sony Favorability Results 2019 on Feb 06, 2019
Sony Favorability amongst integrators improved moderately compared to their 2017 favorability results, with a modest net positive...
Camera Course Winter 2019 - Last Chance on Jan 24, 2019
This is the last chance to register for the Winter 2019 Camera Course. This is the only independent surveillance camera course, based on in-depth...
Testing Bandwidth Vs. Low Light on Jan 16, 2019
Nighttime bandwidth spikes are a major concern in video surveillance. Many calculate bandwidth as a single 24/7 number, but bit rates vary...
WDR Tutorial on Jan 11, 2019
Understanding wide dynamic range (WDR) is critical to capturing high quality images in demanding conditions. However, with no real standards, any...
Worst Products Tested In Past Year on Jan 09, 2019
IPVM has done over 100 tests in the past year. But which products performed the worst? Which ones should users be most aware of? In this report,...
2019 Video Surveillance Cameras Overview on Jan 07, 2019
Each year, IPVM summarizes the main advances and changes for video surveillance cameras, based on our industry-leading testing and...

Most Recent Industry Reports

Eagle Eye Favorability Results 2019 on Mar 21, 2019
Eagle Eye has been the biggest spender in the cloud VMS market including (via their owner) acquiring Brivo for $50 million and CameraManager from...
Large Hospital Security End User Interview on Mar 21, 2019
This large single-state healthcare system consists of many hospitals, and hundreds of health parks, private practices, urgent care facilities, and...
Silicon Valley Cybersecurity Insurance Startup Coalition Profile on Mar 20, 2019
Many industry people believe cybersecurity insurance is not worth it, as the voting and debate in our Cybersecurity Insurance For Security...
Covert IP Camera Shootout - Axis, Hanwha, Hikvision, March, Vivotek on Mar 20, 2019
Covert cameras were one of the last holdout areas for analog cameras. However, in the past few years, IP / HD covert cameras have become...
Top Metrics For Ensuring Integrator Profitability - Statistics on Mar 20, 2019
How do integrators ensure the profitability of their projects? As part of our profitability study, 100+ integrators answered the following...
Avigilon Launches 'Renewed Products Program' on Mar 19, 2019
There are lots of 'pre-owned' cars but pre-owned IP cameras? While such programs are common in other industries, in video surveillance, they are...
Hanwha Tax Evasion Probe, Camera Division Implicated on Mar 19, 2019
A Hanwha group subsidiary was raided as part of a tax evasion probe. While a Korean news media report listed the raided entity as 'Hanwha...
Genetec Security Center 5.8 Tested on Mar 19, 2019
Genetec has released Version 5.8. This comes after a wait of more than a year that caused frustrations for many Genetec partners. Our previous...
Retired Mercury President Returns As Open Options President on Mar 18, 2019
Open Options experienced major changes in 2018, including being acquired by ACRE and losing its President and General Manager, John Berman who...
Large US University End-User Video Surveillance Interview on Mar 18, 2019
Schools have become targets in modern days of active shooters and terrorist fears. The need for video and access security is high. Universities...

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