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June 24th: Store is closed for Quebec National Holiday. Orders placed that day will ship on June 25th.
ZWO CS Lens 2.8mm-12mm F1.4

ZWO CS Lens 2.8mm-12mm F1.4

by ZWO
SKU ZWO-LENS-2.8-12
$38.00 - $38.00
$38.00
$38.00 - $38.00
$38.00
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  • 2.8mm to 12mm Zoom Focal Length
  • Fast f/1.4 Aperture
  • ~100° Wide Field of View
  • Designed for 1/3" Format Sensors
  • Standard CS-Mount Thread
1 in stock
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • ZWO 2.8mm - 12mm f/1.4 CS Lens

    The ZWO 2.8mm - 12mm f/1.4 CS Lens transforms your small-format planetary camera into a dedicated all-sky instrument. Its variable 2.8mm to 12mm focal length provides a field of view up to approximately 100 degrees, while the fast f/1.4 aperture gathers enough light for capturing transient events like meteors. This lens is specifically engineered for cameras with 1/3" sensors, such as the ZWO ASI120 series.

    2.8mm to 12mm Zoom for Framing the Sky

    The key to this lens is its flexible 2.8mm to 12mm zoom range. At 2.8mm, you can capture an immense swath of the sky, perfect for monitoring meteor showers or imaging the entire Milky Way band. Zooming in towards 12mm allows you to frame specific large constellations or regions of interest without swapping equipment, giving you compositional control directly at the lens.

    The f/1.4 Advantage for Faint, Fast Events

    An f/1.4 focal ratio is exceptionally fast, maximizing light collection in short exposures. This is critical for capturing the fleeting streaks of meteors, which last only a fraction of a second. The wide aperture allows you to use higher frame rates and lower gain on your camera, resulting in cleaner, less noisy video captures of atmospheric phenomena or auroral displays.

    CS-Mount Integration for 1/3" Sensors

    This lens uses the standard CS-mount, designed to match the small chip size of 1/3" format guide and planetary cameras. This ensures the entire sensor is illuminated without vignetting and that the resolution is matched to the camera's capabilities. Note that to connect this lens to a standard ZWO camera with T2 threads, you will need a separate T2-CS adapter.

    • Direct Compatibility: Optimally pairs with cameras like the ZWO ASI120MC/MM.
    • Adapter Required: A T2-CS or M42-CS adapter is necessary for connecting to most ZWO cameras.
    • Use Case Limitation: The small image circle is not intended for larger format deep-sky cameras, which would show severe vignetting.

  • What cameras work best with the ZWO 2.8-12mm CS Lens?

    This lens is designed for cameras with a 1/3" sensor format. The classic pairing is with the ZWO ASI120 series cameras. Using it with a camera that has a larger sensor will result in a small image circle in the center of the frame and heavy vignetting.

    Do I need an adapter to attach this ZWO lens to my camera?

    Yes. Most ZWO cameras feature a female T2 (M42x0.75) thread on the front. To attach this CS-mount lens, you will need a T2-CS adapter, which is sold separately. This adapter provides the correct threading and spacing.

    How can I use the ZWO 2.8-12mm lens to capture the Perseid meteor shower?

    For the Perseids, set the lens to its widest focal length (2.8mm) to maximize the sky coverage. Point your camera towards a dark part of the sky about 45 degrees away from the radiant in Perseus. The fast f/1.4 aperture will allow you to capture even faint meteors using short video exposures in a program like SharpCap or FireCapture.

    Is the ZWO 2.8-12mm lens good for imaging planets or galaxies?

    No, this lens is not suitable for planetary or deep-sky imaging. Its extremely short focal length (2.8mm-12mm) is designed for ultra-wide-angle views of the sky. For planets, you need the long focal length of a telescope, and for most galaxies, you need a much longer focal length instrument to resolve any detail.

    What does the "fisheye" effect mean for this ZWO lens?

    At its widest 2.8mm setting, the lens will exhibit significant barrel distortion, often called a "fisheye" effect. This means straight lines (like building edges) will appear curved, and constellations near the edge of the frame will look stretched. This is a normal optical characteristic of very wide-angle lenses and is necessary to achieve the ~100-degree field of view.

    Can I use filters with the ZWO 2.8-12mm CS lens?

    This lens does not have a standard front filter thread like a DSLR lens. It is designed for unfiltered, wide-field imaging of the night sky, such as for meteor showers or capturing the Milky Way in true color with a one-shot-color camera.

  • SKU ZWO-LENS-2.8-12
    Focal Length 2.8mm - 12mm
    Aperture f/1.4
    Mount CS-Mount
    Recommended Sensor Format 1/3"
    Field of View (approx.) ~100°

    • 2.8mm - 12mm f/1.4 CS Lens

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  • ZWO 2-Year Limited Warranty