Support article about camera setting basics

Camera setting basics

When it comes to giving some setting recommendations, there is not one single answer for so many different possible setups. Camera settings are a work of art that start with basic understanding of camera technology. This article helps you understand how Avonic PTZ cameras work and how you can get the most out of it.

Recommendations

– Lighting: ideally always add more light when it is possible (lack of light can end up sometimes in some false “focus issues” especially if the camera is not configured accordingly to the current light conditions, refer to “Why is my camera out-of-focus?“). Avoid filming light sources. 
– Zoom: if possible, avoid to use the full zoom (maybe consider a camera with more zoom if available, or get the camera closer to the object). The need to use the full zoom range causes the lens to be physically in the back of the lens tube, causing less light to fall onto the lens and sensor. The second thing happening is the focus having difficulty because the lens is at its endpoint.
– Placement: Be sure to have your camera set on a stable platform, not prone to vibrations. The further the camera needs to zoom in on the filmed scene or object, the less light will fall onto the sensor. Place the camera as close as possible to the subject.  

Camera settings

First thing you need to do is to ensure that the hardware is set up correctly (Shutter, Iris and PTZ position) before adding any digital image processing.

Exposure:

There are basically two scenarios regarding light conditions: dynamic (office spaces with windows) and fixed (studios) as explained below.

Dynamic light conditions
By default, the camera opens the Iris as far as needed to let in as much light as possible, however this can introduce focus and depth of field issues in dark rooms (again the importance of light), refer to “Why is my camera out-of-focus?“. Automatic Exposure mode (the camera will determine automatically the iris and shutter settings) will be preferred in most cases. If required, you can opt to use the AAE (Aperture Automatic Exposure) or SAE (Shutter Automatic Exposure) mode. Using the AAE or SAE mode requires a more thorough understanding of camera technology. We’ll explain the basics below. 

AAE mode 
The Aperture Automatic mode let’s the user set the size of the opening of the Iris while the camera determines the optimal shuttertime setting. Setting the Iris can be a useful tool to create a larger/deeper Depth of Field. Objects or persons over a larger difference in distance can be brought into focus.  In short; closing the Iris a couple of steps creates a more focused image because the light entering the lens through a smaller hole, creates a more focused beam of light on the sensor. 

SAE mode
The Shutter Automatic mode lets the user set the amount of time per second per frame that the sensor is exposed to light. This value is expressed in parts of a second, for example 1/100. This means that each frame is exposed for one 100th of a second. The shutter always runs at 60 frames per second and is not the same as the output resolution setting on the camera. As you increase the shuttertime, the video will become blurred, sometimes perceived as out of focus. The upside is that with a higher shuttertime (1/25 for example), the amount of time and light is increased and the filmed scene becomes brighter. 

SAE is generally used for scenes with a lot of (fast) motion. 

  • Fast shutter speed (1/10000th of a second = 0.1 milliseconds) : gets an image clear even with fast movement, but less light falls on the sensor (resulting in a dark image where more gain would be needed but this one may add finally more noise..)
  • Low shutter speed (1/25th of a second = 40 milliseconds): more light (per frame) falls on the sensor but fast movement can become blurry and fade on the other hand..
Low Shutterspeed
Low Shutter Speed – Fast movement becomes blurry, more light falls on the sensor.
High Shutterspeed
Fast Shutter Speed – Clear with fast movement, less light falls on the camera.

Digital image processing 

  • DRC -Dynamic Range Compression-, which compresses the natural dynamic range of the image by taking out the darkest and lightest parts
  • Gain limit, which specifies the maximum level of Gain (Gain is the artificial brightness and contrast that the camera can automatically add to the image. It has to be used very carefully otherwise it can end up in adding noise to the picture in dark areas and producing a washed out, greyish picture!)
  • Brightness – Brightness brightens the entire image, 
  • Contrast – Contrast changes the scale of difference between dark and bright. 
  • Gamma – gamma defines the curve with which the sensor (linear) perceives light and dark.

    Note: There would be also more settings to talk about (EV -Exposure Value-, BLC -Back Light Compensation-, Flicker), please refer to the camera user manual.

Focus

Manual focus is useful when the contents of the filmed object are not clear towards the background and the autofocus has difficulty finding the correct focusing (or what can happen for instance when the person or object can not be in the center of the screen). Also it would be usually preferred in controlled situations where the distance between the camera and the person or object barely varies.

Autofocus is useful if the filmed person or object is in the center of the image or if you have no way to control the manual focus while in a recording situation. Please remember the fact that autofocus is not ‘the way to go’ under all circumstances, it is not necessarily always providing the best solution as the end result is put in the hands of an algorithm.

Noise reducation

NR-2D : Used for still-standing objects.
NR-3D : Used for moving objects.

Useful to soften the image when noise is present due to poor lighting conditions. The higher the amount of noise reduction, the softer the image will get, ultimately resulting in loss of details.

Note: be careful when adjusting the noise reduction, as it can take away the natural ‘crispness’ of the image. You will lose the natural ‘crispness’ of the image, if you set the dynamic contrast and gain too high (this will cause more noise). Better practice is to add light to the filmed object.

Color

WB mode auto
The camera continuously measures and defines the light conditions and acts accordingly. In this mode, there are some adjustments that can be made to tune the image to the preference of the user.

Saturation
How saturated the image’s colors are. Lower values result in less saturation, higher in more saturation. As IP streaming cuts out some color information, it can be useful to put the value at 130%/140%. 

Auto White Balance (AWB) SensitivityThis setting indicates how quickly the camera responds to changing light settings.

Conclusion

From reading the above, it is clear that it would be difficult to give an advice on the best setting. It all depends on the situation. There is no one right setting, it takes a fair bit of knowledge and practice to get an optimal result.

Contact our dedicated support team

Avonic’s dedicated support team is there to help you when you need technical support with a project or one of our products. Besides that, Avonic also shares its knowledge with the help of a knowledge database for our customers to benefit from. Visit support.avonic.com for a great source of inspiration of contact our support team via support@avonic.com.

Martijn van Bodegom – Product Manager
Daniël de Bakker – Product Specialist
Stephane Pourcelot – Technical Trainer
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