At a Glance
7mm
Focal Length
40°
Apparent FOV
14mm
Eye Relief
1.25"
Barrel Size
Score Breakdown
Overview
The SVBONY SV135 is a 7-21mm zoom eyepiece designed to replace several fixed focal length eyepieces in your kit. For a beginner or someone building out a first eyepiece collection, that versatility matters. At the wide end, 21mm gives you a broader field for star clusters and sweeping lunar views, while dialing down to 7mm pulls in more magnification for planetary detail and tight double stars.
The field of view shifts between 40 and 57 degrees across the zoom range, which is workable but narrower than dedicated wide-field eyepieces you might use for deep sky objects. The 6-element, 4-group optical design is fully multi-coated, which helps with contrast and light transmission compared to basic Plossl designs. Eye relief sits between 16.3mm and 18mm, making it genuinely usable for eyeglass wearers across the full zoom range.
The 1.25-inch barrel fits virtually any standard telescope. At $39.99 with over 1,400 Amazon reviews averaging 4.5 stars, it has a track record worth noting. It will not replace premium single focal length eyepieces for critical observing, but as a flexible, affordable workhorse, it earns its place in the case.
Key Features
- Covers 7mm to 21mm in a single eyepiece, reducing the need to swap eyepieces during a session
- Fully multi-coated 6-element optics provide noticeably better contrast than standard Plossl eyepieces
- Eye relief of 16.3-18mm across the zoom range accommodates eyeglass wearers comfortably
- Standard 1.25-inch barrel fits virtually all consumer telescopes without adapters
- Field of view ranges from 40 to 57 degrees, suitable for both planetary and wide-field lunar work
- Full metal body adds durability and feels solid compared to plastic-barreled budget eyepieces
- At $39.99, it offers a practical entry point without committing to multiple individual eyepiece purchases
Specifications
| Focal Length | 7mm |
| Apparent FOV | 40° |
| Eye Relief | 14mm |
| Barrel Size | 1.25" |
| Design | Zoom |
| Elements/Groups | 6/4 |
| Series | SV135 |
| Coating | Fully Multi-Coated |
| Waterproof | No |
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Amazon Reviews
This eyepiece helps cancel/absorb some light and allows for more clarity when viewing in the suburbs. (My backyard) After about 5 min adjusting eyes, many more distant items became visible with this eyepiece, than any other I have. The ability to zoom with 1 piece eliminates the hassle of changing, ...
To be fair, I don't have any experience with other Zoom eyepieces, but this SV135 model from SVBONY works very well. The title to this review is because you get 5 different focal lengths from 7mm to 21mm, and you can figure out what works best for you before you spend more money on individual eyepie...
The media could not be loaded. I noticed early on after receiving this SVBONY eyepiece that something didn’t seem quite right—there was a broken plastic piece on the bottom end. I wasn’t sure exactly when it broke, but once I realized it, I contacted SVBONY’s customer service. They were incredibly h...
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