SLT (Single-Lens Translucent)

Sony's Single-Lens Translucent (SLT) technology marked a unique approach in digital camera design, blending features of DSLRs and mirrorless systems. This guide explains the SLT concept, its timeline, and its place in the camera evolution landscape.

Understanding SLT Technology

SLT stands for Single-Lens Translucent, a camera technology developed by Sony that uses a fixed translucent mirror instead of the traditional moving mirror found in DSLRs. This mirror partially reflects light to the autofocus sensor while allowing the rest to pass through to the imaging sensor, enabling continuous autofocus tracking even during video recording or high-speed continuous shooting.

Introduction and Advancement of SLT Cameras

Sony introduced SLT cameras in 2010 with the aim of offering DSLR-like performance, particularly in autofocus speed and accuracy, without the bulk and noise of a moving mirror mechanism. The technology was phased out as Sony shifted focus to mirrorless systems, with the last SLT models announced in 2016.

Examples of Sony SLT Camera Models

Notable SLT models included the α33 and α55, which were among the first to be introduced, followed by advanced models like the α77 and the high-end α99. These cameras were well-regarded for their fast shooting speeds and real-time autofocus capabilities.

SLT vs DSLR vs Mirrorless

SLT cameras stood out from traditional DSLRs by offering full-time phase-detection autofocus, a feature DSLRs could only use when not in live view or video mode. Compared to mirrorless cameras, SLTs had an optical path similar to DSLRs, which gave them an edge in autofocus performance at the time. As mirrorless technology improved, however, the advantages of SLTs diminished, leading to their discontinuation in favor of the more compact and equally capable mirrorless format.


Sony's SLT technology represented an innovative step in camera development, providing a unique combination of speed and performance. While SLT cameras are no longer in production, they played a significant role in the transition from DSLRs to the mirrorless era, influencing the camera market with their groundbreaking features.

Whether you're exploring camera history or considering a second-hand SLT model, understanding this technology can provide valuable insights into the evolution of modern photography equipment and its impact on photography techniques.