PrimaluceLab SESTO SENSO 3 LS

SESTO SENSO 3 LS is the robotic focusing motor designed specifically for precision motorized focusing of telephoto photographic lenses (Canon, Nikon, and others). Developed and manufactured in Italy by PrimaLuceLab, SESTO SENSO 3 LS builds on the technology of SESTO SENSO 3 and introduces the new Lens Gear Clamp (LGC), a custom mechanical interface that directly connect the motor to photographic lenses to rotates the focus ring of compatible photo lenses with extreme precision and without backlash, eliminating the need for external belts (although a belt is optionally available for lenses with very stiff focus mechanisms) and offering an integrated position encoder that keeps track of motor position even during manual adjustments, with Automatic Position Recovery option. The LGC also features an Arca-Swiss style mount, allowing SESTO SENSO 3 LS to be easily attached to one of our PLUS Vixen-style dovetail bars and mounted on any telescope mount equipped with a standard Vixen clamp.

With USB-C and built-in WiFi connectivity, you can control SESTO SENSO 3 LS from your computer or wirelessly via the Virtual HandPad using a smartphone or tablet. Its high-precision motor delivers 2 million steps resolution, making it ideal for astrophotography with photographic lenses. Compatible with ARCO rotators, ASCOM drivers, and PLAY software, supporting EAGLE’s GHOST mode, and DARK mode with dimmable LED lights, SESTO SENSO 3 LS sets a new standard in robotic focusing for imaging with telephoto lenses.

SESTO SENSO 3 LS is our most advanced robotic focusing motor for telephoto photographic lenses

Built upon the success of the first and second generation motors, the SESTO SENSO 3 LS adds exclusive features specifically designed for imaging with photographic lenses, incorporated into a single enclosure to house all the elements that comprise a motorized focusing system for astrophotography.

Compact, lightweight and all-in-one design

SESTO SENSO 3 LS features a compact and lightweight enclosure that integrates all control electronics, with all ports conveniently located on the side. The unit includes dimmable status LEDs, which can also be turned off completely to avoid stray light during nighttime imaging sessions with photographic lenses. Connectivity is streamlined and efficient: a USB-C port allows connection to an EAGLE or any Windows® computer using the included USB cable; the dedicated ARCO port enables both power and control of an optional ARCO camera rotator through a single cable; the 12V power port (5.5/2.5mm, center-positive) supplies power to both the motor and internal electronics using the included cigarette lighter-style cable (or with an optional cable for direct connection to the EAGLE); and a temperature sensor port lets you connect the optional probe for use with third-party software that supports automatic focus compensation based on ambient temperature changes.

Easy installation with Lens Gear Clamp (LGC)

SESTO SENSO 3 LS features the new Lens Gear Clamp (LGC), specifically designed for telephoto photographic lenses such as Canon, Nikon, and other models with manual focus rings. This innovative gear-based design eliminates mechanical backlash and ensures smooth, precise motorized focusing without the need for external belts. The integrated rubber gear directly engages the lens focus ring, while the Arca-Swiss style mount allows you to secure SESTO SENSO 3 LS to a PLUS Vixen-style dovetail bar for perfect alignment. Manual focusing is still possible at any time by rotating the lens’s focus ring, while the integrated encoder keeps track of the motor’s position—even after manual adjustments. This makes SESTO SENSO 3 LS ideal for astrophotographers who want the precision of a robotic focusing motor combined with the freedom of manual control.

If your telephoto lens does not include an L-bracket with photo thread for mounting to the PLUS Vixen-style dovetail bar, we offer an optional Secondary Support for Photo Lenses—a dedicated accessory that ensures proper stability and alignment when using SESTO SENSO 3 LS.

To provide optimal grip on different lens focus rings, SESTO SENSO 3 LS comes with two interchangeable rubber gears: one for lenses with focus rings up to 18mm in width, and one for lenses with focus rings thicker than 18mm. This ensures maximum contact and precision across a wide range of compatible lenses. SESTO SENSO 3 LS is compatible with many photographic lenses, such as (but not limited to):

Nikkor Z 70-200mm f/2.8 Vr S
Nikkor Z 100-400mm f/4.5-5.6 VR S
Nikkor Z 24-120mm f/4 S
Nikkor Z 24-70mm f/4 S
And other telephoto lenses with manual focus ring

Integrated encoder: precise control with freedom of movement

SESTO SENSO 3 LS integrates a high-resolution position encoder that tracks the movement of the motor shaft with extreme accuracy. This allows the user to manually rotate the focus ring of the photographic lens, with SESTO SENSO 3 LS installed and powered on, without losing the motor’s reference position. Ideal for astrophotographers who need to fine-tune focus manually before switching to fully automated control, this feature also improves the initial calibration process.
Another advantage of the integrated encoder is its ability to detect and compensate for small shifts in focus caused by lens mechanics. With this Automatic Position Recovery function, SESTO SENSO 3 LS can also automatically move the lens focus ring back to the previous position if it is rotated manually or accidentally shifted. You can define a recovery delay (from 0 seconds for instant reaction up to 20 seconds). Please note that the encoder detects motor shaft movements only and cannot account for internal mechanical slips in the lens focusing mechanism.

SESTO SENSO 3 LS: dimensions and weight

SESTO SENSO 3 LS includes all these advanced features in a lightweight, compact all-in-one chassis specifically designed to be installed on telephoto lenses without the need for external brackets or adapters. SESTO SENSO 3 LS weighs just 515 grams (1.1 lbs). In the picture you can see the dimensions.

Technical Specifications

In the Box

• SESTO SENSO 3 LS
• Arca-Swiss clamp
• 6mm and 18mm thick rubber gears
• USB-C to standard USB-A cable
• 12v DC cigarette-style plug power cable
• Hex keys for assembly
• Quick installation guide

Manuals & Warranty

PrimaluceLab 1-Year Warranty