S1755 Lens-to-Telescope Converter for Sony A

Description

The S1755 turns a compatible Sony A-mount SLR/SLT lens into an upright-viewing telescope for direct observation.

Compatibility: Sony A-mount SLR/SLT lenses only. Sony E-mount lenses, including FE lenses, and other mirrorless lenses are not supported.

Another way to look while out shooting

Keep one lens on your camera and turn a spare compatible telephoto lens into a monocular to observe distant subjects and find your next composition. The compact converter takes up only a small corner of your camera bag, adding a second use to a lens you already carry without packing a separate telescope.

A new purpose for a familiar lens

Moving to a mirrorless camera need not leave your SLR telephoto lens sitting on a shelf. Fit the converter for its mount and bring it back into use for distant observation—another reason to take a familiar lens on your next outing.

Mechanical aperture control

The converter opens the lens's mechanical aperture lever to keep the aperture open. This is mechanical actuation, not electronic aperture control.

A considered optical path

Our offset optical design uses a total-internal-reflection prism system to erect the image, without reflective coatings on the reflecting faces. The intermediate image forms in air rather than inside glass. No additional focal-extending lens group is needed, reducing the influence of added optics and helping preserve the lens's imaging performance.

A 10mm eyepiece with its own focus adjustment

Divide the lens focal length by 10mm to calculate magnification: a 70–200mm zoom becomes a 7–20x telescope. The adjustable eyepiece works with the lens's focus ring for fine adjustment. A macro lens or suitable close-up accessories also enables close-range observation.

Effective light acceptance is limited to f/4, including with faster lenses, to control the effect of marginal rays on image quality. Slower lenses remain limited by their own aperture.

Specifications

Field of view: approximately 55°
Eyepiece focal length: 10mm
Optical construction: 7 elements in 3 groups
Construction: precision-machined metal body; optical glass with MC broadband anti-reflection coatings

Included

Converter, front and rear protective caps, and a thick padded protective pouch.

Use

Attach the converter as you would attach the lens to a camera. Operate the release mechanism before removal. Where applicable, set the lens to manual focus. Never look directly at the sun through the lens or converter.