Focus
This article will guide you through some useful steps in troubleshooting your Axis network cameras.
1. Factors affecting the focus
1.1 Bubble influence
1.1.1 Optimal image with the dome/front glass
Axis focus mechanism and especially the autofocus are optimized to work with the dome/front glass coming with the camera only. Using either a different or no dome or placing the camera behind additional glass constructions could affect the focus performance.
1.1.2 Dirty or scratched dome bubble and front glass
A dirty or scratched bubble/front glass will affect the image quality, making it especially hard for the autofocus. For some PTZ devices it is always good to test on different areas of scene/dome areas and detect if the result is the same across different dome areas and zoom levels.
Possible mitigation
- Be careful not to scratch or damage the dome cover/front glass. Do not clean a dome cover/front glass that looks clean to the eye and never polish the surface. Excessive cleaning can damage the surface.
- For general cleaning of a dome cover/front glass it is recommended to use a non-abrasive, solvent-free neutral soap or detergent with water and a soft cloth. Rinse well with clean lukewarm water. Dry with a soft cloth to prevent water spotting.
- Never use harsh detergents, gasoline, benzene or acetone, etc. and avoid cleaning in direct sunlight or at elevated temperatures.
1.1.3 Double image effect
Depending on the model, the bubble dome might have a visual effect near the horizon
Possible mitigation
- Mount the camera higher
- Limit the tilt level
- Lower the zoom at this higher tilt positions , the effect is more visible in high zoom levels
1.2 Object proximity
Objects that are close by can be ignored by the autofocus mechanism depending on distance of the objects to the camera and a value set in the camera – the “near focus limit” (generally 3m).
1.2.1 Near focus limit
The near focus limit can be set to avoid focusing on objects too close to the camera, hence making it a good way to help the camera speed up focus on the desired range/distance. The camera will simply ignore the near focus zone. It’s recommended to test focus issues with the lowest value temporary.
Possible mitigation
- Change the near focus to a lower value in the camera GUI.
1.3 Light influence
1.3.1 Optimal light scene
The best way to test an autofocus behavior is to start with a strong neutral light and strong contrast scene (strong illuminated scene). The autofocus mechanism is based on the amount of light and contrast detection. The focus behavior can also differ depending on what type of optics the camera model is based on.
1.3.2 Mixed-light
The most difficult scenes for our cameras are mixed light conditions where no dominant light sources are available. This is making it difficult for the focus algorithm to find the right focus point to provide a good image.
Possible mitigation
Some cameras support an adjustable focus trace curve or an automatic function within the camera block to focus on the "strongest" light source (either IR-light or normal light) available in the scene. You can set this value manually in the PlainConfig:
- Normal => Visible light
- 850nm => IR Light
- 950nm => IR Light
The focus trace curve is only applicable when the IR cut filter is “off”.
1.3.3 Light sources in traffic surveillance
Typical installations such as traffic surveillance with many light sources in combination with movement (cars) make it hard for the camera to focus properly. The behavior of the camera will appear as “Hunting Focus”.
Possible mitigation
- Gain / noise reduction
In such scenes it might help to reduce Gain and disable the noise reduction to help the camera finding the focus faster. Remember that with noise reduction disabled the noise may increase and could affect the AF search negatively in some cases.
- Point light focus mode
In specific situations, e.g. city surveillance with many light sources and especially the head lights from cars, could make it difficult for the camera to focus. To help the camera handle those situations, a special Auto focus mode, called Point Light has been implemented in some of our PTZ products like Q6115-E or Q6114-E. The point light mode will shrink the sensitive search area for the autofocus and increase the Near Focus Limit in order to reduce the number of point lights and to make it easier for the autofocus to find a good focus point. Please see below a generic illustration.
1.4 Optics influence
Some devices might have lenses that can be replaced and adjusted. The optics might require a readjustment.
1.4.1 Manual focus
Some models of camera have issue where they don’t have good focus from the start.
Possible mitigation
- For cameras like M1045/M1065 which have a focus ring, please follow the instructions in the manual in order to focus the camera using the focus ring.
1.4.2 Optics replacement
Focus issues after replacing a lens.
Possible mitigation
-
When installing a lens, it is important to start with factory defaulted camera and lens connected to the camera and then powering it up.
- Please follow the instructions in the user manual.
- It is very important that C to CS mount ring is in place for some lenses.
- Calibrate focus with this command from web browser address field:
http://camera_IP/axis-cgi/opticssetup.cgi?calibrate=focus - You need to follow instructions given by the interface which means that when you press Autofocus button first time you get the message that you need to manually configure focus on the lens first. That is done by using physical focus ring on the lens itself.
- After setting focus manually as good as possible, you can proceed to press Autofocus again for additional fine tuning of focus. It is also possible to use manual focus control and go more towards near and far in focus.
- One additional thing to try as well is to rotate lens upside down physically and see if that gives any difference.
- Note that for P-Iris lenses we have more close names of the drivers to select between and for all DC Iris type of lenses you select Generic DC Iris option.
1.5 Heavy vibrations influence
Shocks and vibrations are one of the main causes that can influence and affect focus of the Axis Fixed Cameras. The shocks and vibrations are seen mainly in installations with strong wind, heavy vehicle traffic street, less stable mounts (inadequate light poles).
Possible mitigation
- If the focus gets better after that the camera gets restarted, then the most possible reason for losing the focus is vibrations. You can confirm this by checking if the camera loses the focus when the wind is a little bit stronger than normal. In this type of issues, the focus is lost gradually over time. It is not recommended to install Axis cameras on inadequate light poles.
- Workaround would be to create a weekly scheduled event and send the VAPIX command to perform Auto-focus as Send Notification:
http://Cam_IP/axis-cgi/opticssetup.cgi?autofocus=perform
2. Opening a support case
It might happen that the above factors and mitigations do nott help identify and solve the focus issue. You are welcome to open a support case and provide the below needed information and data.
Note: It is always important to test the devices on the latest firmware on an LTS track or Active Track if possible.
2.1 Data and information needed
NOTE: Please do not forget to add the server report of the device.
Support tip: How to download a server report
2.1.1 Fixed devices
- Dirt, dust, scratches or damage on the bubble or front glass?
- Does the camera achieve focus if the bubble is removed? (Applies for Fixed Dome Cameras)
- Calibration and auto-focus performed?
- In some cameras temperature correction of focus can change focus slightly. Go to PlainConfig > Image Source and set it to none and see if that helps. (Applies for Fixed Cameras)
- Did you perform a factory default?
- Where is the camera installed? (pole, street traffic, wall)
- When did this happen? After installation or after some time? Is there any pattern?
- Are there other cameras of the same model that have this issue?
- VMS interference? Isolate the camera from the VMS if possible.
2.1.2 PTZ devices
- Did you perform a manual focus?
- Did you perform a PTZ calibration?
- Did you perform a factory default?
- Where is the camera installed? (pole, street traffic, wall)
- When did this happen? After installation or after some time? Is there any pattern?
- Are there other cameras of the same model that have this issue?
- VMS interference? Isolate the camera from the VMS if possible.
- We rely on recordings and pictures for a focus troubleshooting. Before recording or taking pictures, please consider the below:
- Add coordinates in the overlay Preset #P Pan:#x Tilt:#y Zoom:#z Factor:#Z , "Include date", "Include time".
- Make sure the recordings are done on predefined scenes such as Presets. Troubleshooting on the same scenes makes it easier.
- Test the autofocus on different scenes, different areas with different light sources and on different zoom levels.
[Please contact technical support with all questions answered and files attached]
note
Note
Axis cameras will operate as intended if installed as specified by the Installation Guide. Generally, the dome of the device should be facing the ground when operating or testing the devices.
Please note that Axis does not take any responsibility for how the modification of configuration described in this guide may affect your system. If the modification fails or if you get other unexpected results, you may have to restore the settings to default.
The guide does not cover all possible issues but rather covers the most commonly seen through the support cases. As an Axis Customer you are always welcome to contact Axis Support whenever you need with any type of issues listed or not in this troubleshooting guide.