Image Sensor Dynamic Range vs. High Dynamic Range – Key Differences

The terms image sensor’s “dynamic range” and “high dynamic range (HDR)” are related concepts in the field of digital imaging, but they refer to different aspects:

Image Sensor Dynamic Range

1. The dynamic range of an image sensor refers to its ability to capture and represent the range of light intensities in a scene, from the darkest shadows to the brightest highlights.
   
2. It is typically measured in terms of the ratio between the maximum and minimum detectable light intensities, often expressed in decibels (dB) or stops.
   
3. A higher dynamic range means the sensor can capture a broader range of light levels without losing detail in either the shadows or highlights.
   
4. Image sensor dynamic range is a characteristic inherent to the sensor itself and is influenced by factors such as pixel size, sensor size, and sensor technology (e.g., CMOS vs. CCD).
   

Figure 1: Standard Dynamic Range Sensor (Left) and Good Dynamic Range Sensor (Right)

High Dynamic Range (HDR):

1. HDR, on the other hand, refers to a technique used in photography and digital imaging to reproduce a greater dynamic range than what is typically possible with standard imaging techniques.
   
2. In HDR imaging, multiple images of the same scene are captured at different exposure levels, ranging from underexposed to overexposed.
   
3. These images are then merged or processed using specialized software to create a single composite image that preserves details in both the shadows and highlights.
   
4. The resulting HDR image typically exhibits greater contrast and detail than a single exposure image, making it visually appealing and more closely resembling the dynamic range of the human eye.
   
5. HDR imaging can be achieved through techniques such as exposure bracketing, tone mapping, and blending multiple exposures.
   

Figure 2: HDR (Left) and Non–HDR (Right)