S1754 Lens-to-Telescope Converter for Nikon F

Description

The S1754 turns a Nikon F-mount SLR lens into an upright-viewing telescope. Pair it with a telephoto lens to observe distant subjects between shots and put an existing lens to another use.

Compatibility: Nikon F SLR lenses only. Nikon Z-mount 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.

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.

The converter holds a mechanical aperture lever open. Electromagnetic-aperture lenses require model-specific checks.

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

Mount: Nikon F lenses; not for Nikon mirrorless lenses
Eyepiece focal length: 10mm
Optical construction: 7 elements in 3 groups
Field of view: approximately 55°
Construction: precision-machined metal body; optical glass with MC broadband anti-reflection coatings
Dimensions: 55 × 65mm
Weight: 145g

Included

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

Use

Mount as you would a camera body. Use the release button to detach. Set the lens to MF where required for manual focusing. Never look directly at the sun through the lens or converter.