TECH TIPS

May 2000 Surveillance

Cameras and lenses

Back focus adjustment

Note: The lens aperture must be wide open for all back focus adjustment procedures. Therefore, these procedures must be performed in subdued lighting or with the use of filters in front of the lens to reduce the light.

Fixed lens models (indoor method)

1. With the camera operating, view some object at least 20-25 m away.

2. Set the lens focus ring to infinity by rotating it fully clockwise as viewed from the front of the camera.

3. Set the lens iris to its widest usable opening. See note above

4. Adjust the imager position to bring the object being viewed into sharpest focus.

Fixed lens models (outdoor method)

1. Point the camera at some object which is more than 60 m away.

2. Set the lens focus ring to infinity by rotating it fully clockwise as viewed from the front of the camera.

3. Turn the camera on and hold an ND 3.0 metallised filter in front of the lens. Make sure the lens iris is set to the widest usable opening. See note.

4. Adjust the imager position to bring the object being viewed into sharpest focus (with filter in place).

Zoom lens models

1. With the camera operating, view some object at least 20-25 m away.

2. Make sure the lens iris is wide open. See note above.

3. Set lens focus to extreme FAR.

4. Adjust lens zoom to extreme WIDE angle. (Widest field of view.)

5. Adjust the imager position on the camera to obtain the best focus.

6. Move lens zoom to extreme TELEPHOTO. (Smallest field of view.)

7. Adjust lens focus (by the controller) for best picture.

Monitors

Recommended set-up of video monitors for maximum

CRT performance

Video monitors are designed to give the user a wide range of operation by providing externally accessible adjustments. These controls may include vertical and horizontal hold, vertical linearity and height and, most important, brightness and contrast. The key to achieving maximum life from the CRT (kinescope) is proper adjustment of the brightness and contrast. Operation of the CRT at excessive levels of brightness and contrast can shorten tube life and lead to premature failure.

To prevent this situation of operating above the required conditions for normal viewing of the video monitor, a simple procedure can be used. After the video monitor has been installed, set room lighting at the level which will exist during actual operation. Turn both the brightness and contrast controls to the minimum setting. Next, turn the brightness control up until a very faint glow can be seen on the CRT raster area. Allow your eyes to become conditioned to viewing this faint glow. Usually several seconds is adequate. Adjust the brightness control down until the glow just disappears and then turn the brightness up until the glow just reappears. Now that the brightness control is set, the contrast control can be adjusted. Turn the contrast control up until the video information can be seen. Adjust the contrast control up until a level is obtained for comfortable viewing of the screen. Do not set the contrast level high enough to cause smear. If present, smear will be evident in the white portion of the video screen.

Proper adjustment of the video monitor controls will extend the life of the CRT. Be kind to your monitor; it is a key ingredient of your system.

Source: Tech Tips provide extra technical notes developed by Philips' application engineers in response to user's applications questions.





Share this article:
Share via emailShare via LinkedInPrint this page



Further reading:

Hikvision launches AcuSeek NVR
Surveillance Products & Solutions AI & Data Analytics
By integrating natural language interaction, Hikvision’s AcuSeek NVR enables precise video and image retrieval within seconds, marking a transformative milestone for the security industry's advance into intelligent and efficient applications.

Read more...
2025 video surveillance market set for improved fortunes
News & Events Surveillance
Novaira Insights has unveiled its latest report, World Market for Video Surveillance Hardware and Software – 2025 Edition, forecasting a healthy growth rate of 8,1% until 2029, excluding China.

Read more...
Dallmeier and Hexagon form a technology partnership
Surveillance
Dallmeier and Hexagon have agreed to form a technology partnership, which will see the two companies combine their expertise to develop integrated security solutions for various application areas, particularly critical infrastructures.

Read more...
Analyse, automate, and optimise logistics processes
neaMetrics Surveillance Transport (Industry) Products & Solutions Logistics (Industry)
In today’s rapidly evolving logistics sector, the pressure to improve process efficiency, optimise resource usage, and ensure seamless security is more intense than ever. Smart, proactive surveillance is no longer a luxury — it is a critical operational necessity.

Read more...
Safer spaces through smart surveillance
NEC XON Surveillance
Advances in facial recognition technology are transforming surveillance from a mere recording tool into an intelligent, integrated system that enhances real-time safety, moving beyond the traditional expansion of CCTV efforts.

Read more...
Next generation of AI-powered video telematics
IoT & Automation Surveillance Transport (Industry)
Webfleet, Bridgestone’s fleet management solution in South Africa, has launched Webfleet Video 2.0, an AI-powered solution designed to enhance fleet safety, security, compliance with local regulations and operational efficiency through real-time video insights.

Read more...
Key design considerations for a control room
Leaderware Editor's Choice Surveillance Training & Education
If you are designing or upgrading a control room, or even reviewing or auditing an existing control room, there are a number of design factors that one would need to consider.

Read more...
Smart cities and the role of video security
Surveillance Integrated Solutions
As cities around the world continue to embrace smart technology, including IoT that not only connects to people, but also the surrounding activity, the integration of advanced video security systems is crucial to ensure safety and efficiency in environments.

Read more...
How intrusion protection helps secure O&G operations
Surveillance Perimeter Security, Alarms & Intruder Detection Industrial (Industry)
For O&G operators in Africa, physical security remains one of the biggest considerations, particularly when it comes to perimeter protection and the ability to mitigate intruder-related incidents.

Read more...
Axis secures the Waterfront
Surveillance Entertainment and Hospitality (Industry) Retail (Industry)
Axis Communications shares insight into its longstanding partnership with the V&A Waterfront, one of Africa’s premier retail and mixed-use precincts, through its latest, updated customer success story.

Read more...










While every effort has been made to ensure the accuracy of the information contained herein, the publisher and its agents cannot be held responsible for any errors contained, or any loss incurred as a result. Articles published do not necessarily reflect the views of the publishers. The editor reserves the right to alter or cut copy. Articles submitted are deemed to have been cleared for publication. Advertisements and company contact details are published as provided by the advertiser. Technews Publishing (Pty) Ltd cannot be held responsible for the accuracy or veracity of supplied material.




© Technews Publishing (Pty) Ltd. | All Rights Reserved.