Last updated: 19 September 2025

Light Sensitivity: Sony IMX183 vs Onsemi AR2020

Light sensitivity is a critical parameter in selecting industrial cameras for low-light imaging applications. This article presents a comparative evaluation of two sensors: the Sony IMX183 and the Onsemi AR2020, as implemented in the MER2-2000-19U3M and MER2-2002-20U3M cameras, respectively.
By analyzing tests performed by adjusting gain, varied exposure times and digital signal amplification, the study reveals the light sensitivity of the two sensors under challenging light conditions.

Light Sensitivity: Sony IMX183 vs Onsemi AR2020

Camera Model	MER2-2000-19U3M	MER2-2002-20U3M
Sensor	Sony IMX183 Rolling Shutter CMOS	Onsemi AR2020 Rolling Shutter CMOS
Resolution	5496 x 3672	5120 x 3840
Total Pixels	20.48 MP	20 MP
Pixel Size	2.4 um	1.4 um
Optical Format	1"	1/1.8"
SNR	42.08 dB	39.41 dB
Standard Gain Range	0 dB - 24 dB	0 dB - 24 dB
Gain (if using Remove Parameter Limits)	0 dB - 27 dB	0 dB - 50.6 dB
Standard Exposure Time	12us - 1s	26us - 1s
Exposure (if using Remove Parameter Limits)	12us - 15s	26us - 15s
Pixel Bit Depth	8-bit, 12-bit	8-bit, 12-bit

Influence of Gain, Exposure and Digital Shift ON IMX183 VS AR2020

The camera uses gain to control the overall brightness of an image.

By increasing the signal from the sensor, gain directly enhances the camera's sensitivity to light, making objects appear brighter even in low-light environments. However, a significant drawback is that increasing gain also amplifies image noise.

Exposure refers to the duration for which the camera's sensor collects light.

By controlling the amount of time, the sensor is active, exposure directly impacts the quantity of light accumulated. Longer exposure times allow more photons to hit the sensor, resulting in a brighter image, which is crucial for capturing details in low-light conditions.

Digital Shift is a feature that multiplies the pixel values of images by 2^n, where n is the digital shift factor. This is achieved by performing a logical left shift by n on all pixel values. For example, a shift factor of 1 multiplies by 2, and a factor of 2 multiply by 4

Digital shift increases the perceived brightness of the image. This can be particularly useful for enhancing the visibility of darker areas or for compensating in low-light conditions when other methods like gain or exposure may be limited. If the camera does not support digital shift, a similar brightness increase can often be achieved using the Gain feature.

Light Sensitivity Tests IMX183 vs AR2020

Baseline Test of IMX183 vs AR2020

Set gain to 0dB. This provides a baseline with no additional noise from amplification.

To establish a fundamental measure of native light sensitivity, both cameras were tested at zero gain (0 dB). Exposure times were incrementally increased from 40 ms to 50 ms, and digital shift (the sensor’s internal capability to amplify the digital output) was applied progressively to the maximum allowed by each model.

At 40 ms exposure with no gain, both sensors produced relatively dark images with limited chart visibility.

Comparison of two camera sensor images with labels 'IMX 183' and 'AR2020' on a dark background.

Increasing exposure to 50 ms and applying maximum digital shift, the Onsemi AR2020 sensor exhibited notably brighter and higher-contrast images than the Sony IMX183 sensor under identical test conditions.

IMX183 and AR2020 cameras viewfinder images with measurement labels and settings.

The IMX183 sensor required more aggressive digital shifting and longer exposure to approach similar image brightness, indicating relatively lower baseline sensitivity.

This initial test demonstrated the AR2020’s edge in detecting lower light levels more effectively.

Two technical diagrams of IMX183 and AR2020 camera lenses designs with labeled specifications.

Digital Gain Test of IMX183 vs AR2020

In the next phase, both sensors were tested at maximum analog gain (24 dB) with a fixed exposure time of 10 ms.

As the analog gain increases from 12 dB to 24 dB, both cameras show a clear increase in image brightness at each gain step. The details of the test chart gradually become more visible in both cameras.

12 dB Gain:

Both sensors produce dark images with only faint chart details visible. The AR2020 offers slightly more even brightness; the IMX183 appears darker overall.

Two images showing sensor performance with different models: IMX183 and AR2020 and settings.

18 dB Gain:

Brightness improves substantially for both cameras, making the chart more visible. The AR2020 maintains a slight advantage in brightness and contrast. Noise becomes more noticeable, especially in dark areas.

Two images showing IMX183 and AR2020 camera sensors performance with different settings.

24 dB Gain (Maximum):

Both cameras reach their brightest images with maximum detail visibility. The AR2020 keeps a marginally higher contrast. However, noise and graininess significantly increase, especially in background and low-contrast regions, reducing fine detail clarity in both sensors.

Two radar sensor models: IMX183 and AR2020 with labeled specifications and gain settings.

Digital Shift Test of IMX183 vs AR2020

Here, both industrial cameras are set at their default maximum gain (24 dB), varying both exposure time and digital shift values.

Maximum Gain + Initial Digital Shift:

At 10 ms exposure and minimal digital shift (shift 1), both cameras display similar brightness and contrast, with the test chart moderately visible.

There is no dominant advantage in either sensor at this setting.

Comparison of two camera models, IMX 183 and AR2020, with technical specifications on a black background.

Maximum Gain + Maximum Digital Shift:

At 10 ms exposure and maximum digital shift (shift 4 for IMX183, shift 2 for AR2020), the IMX183 sensor image becomes extremely bright, almost overexposed, while the AR2020 sensor remains well balanced with good detail and contrast.

This suggests that the wider range of digital shift available in the IMX183 sensor can more aggressively amplify the image signal, but potentially at the cost of dynamic range and risk of overexposure.

Since the image appears overexposed at maximum gain and digital shift settings, reducing the exposure time can help improve detail retention.

Two technical diagrams side by side with labels IMX 183 and AR2020, showing different configurations.

Low Exposure + Maximum Digital Shift:

At a very low exposure time (3 ms), maximum gain, and maximum digital shift, both sensors recover brightness and chart details well, though IMX183 again appears brighter than AR2020.

The AR2020 retains more tonal gradations, whereas IMX183 tends towards lighter mid-tones.

Two camera sensors IMX 183 and AR2020 with technical specifications.

Low Exposure + Equal Digital Shift:

When both cameras are set to the same digital shift (shift 2), at very low exposure and max gain, their brightness levels become similar, but AR2020 generally preserves detail and contrast slightly better.

This comparison highlights that while the IMX183 sensor allows for greater digital amplification, the AR2020 maintains better balance between brightness and detail, making it more effective at preserving image quality under aggressive digital shift conditions.

Two camera sensors IMX 183 and AR2020 with technical specifications and settings displayed.

Expanding Gain Range: Utilizing Remove Parameter Limits for Maximum Sensitivity

Camera parameters typically have factory-defined limits to ensure optimal performance and high image quality. However, for specific applications, users may need to extend these ranges. The "Remove Parameter Limits" feature enables expanding the adjustable range of certain parameters beyond their factory defaults.

When this feature is applied, the maximum allowed gain is extended as follows:

MER2-2000-19U3M: from 0 dB up to 27 dB
MER2-2002-20U3M: from 0 dB up to 50.6 dB

To avoid overexposure at very high gain (50.6 dB), MER2-2002-20U3M exposure time is reduced from 10 ms to 0.5 ms

Two technical diagrams of camera sensors IMX183 and AR2020 with specifications and gain values.

At these extended gain levels, noise becomes a critical factor. Images captured at 50.6 dB gain on the AR2020 show grain and noise, which persist even when other parameters are adjusted.

In contrast, the IMX183 produces a cleaner but noticeably darker image, lacking the brightness boost despite the extended gain range.

In the final test scenario, where both sensors operate at maximum gain, digital shift, and exposure parameters, images become severely overexposed with loss of detail in highlights and bright areas.

Balancing these parameters is essential: while removing limits enables pushing sensitivity further, it also exacerbates noise and potential image degradation, especially in the AR2020 sensor at very high gains.

Comparison of two camera sensor models IMX 183 and AR2020 with gain and exposure time settings.

Conclusions of the light sensitivity of IMX183 vs AR2020

The Onsemi AR2020 sensor generally demonstrates higher light sensitivity than the Sony IMX183. It delivers brighter, clearer images with stronger contrasts and retains more detail in low-light conditions. While it handles gain and digital shift effectively, image noise increases significantly at extreme settings.

In contrast, the IMX183 requires longer exposure or more aggressive digital shift to achieve similar brightness but produces cleaner images with less noise. However, it is more prone to overexposure and loss of highlight detail when pushed too far.

In summary, both the IMX183 sensor and Onsemi AR2020 offer distinct advantages. And the best choice depends on your specific low-light imaging requirements.

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