The apparent field of view and the usable eye relief to stay the same as the focal length changes.
Smooth zoom action with click-stops at 3, 4, 5, 6,7 and 8mm for quick changes to precise preset magnifications.
Parfocal across the entire zoom range (minor tweaking may be necessary, however).
SVBONY SV215 Zoom Eyepiece1.25" 3mm-8mm for Planetary Observation
The SV215 zoom eyepiece is designed to provide the good balance of contrast, comfortable eye relief, and resolution for the critical planetary observer, particularly those with ultra-premium short focal length refractors.
Fold-down Rubber Eye Cup
Apparent Field of View: 56°
The field of view will not change with the change of focal length, the process of doubling to give customers a fixed point to pull into the visual enjoyment.
Eye Relief: 10mm
The transformation ratio customers do not need to adjust the distance of exit pupil, so as to adapt to the observation environment again and improve the observation comfort.
Best For Planetary Observation
Great quality, but difficult insight at highest magnification
|Scenes||observe Venus: Mars; Jupiter; Saturn and so on|
|Apparent Field of View:||56°|
|Blackened Lens Edges:||Yes|
|Barrel Type:||With safety undercut|
|Rubber Eye Guard:||Yes|
1. SV215 zoom eyepiece is a good assistant for you to observe and take pictures of the planets; it is a good helper for the amateur astronomers to observe Venus; Mars; Jupiter; Saturn and so on
2. Adjustable focal length; SV215 3 mm to 8mm zoom eyepiece equivalent to multiple eyepieces; SV215 eyepiece is much better than the kit eyepieces; this helps you to zoom in and out rather than changing lens
3. Parfocal across the entire zoom range; minor tweaking may be necessary; you do not need to refocus every time you change the focal length
4. Constant field of view and eye relief; the apparent field of view and the usable eye relief to stay the same as the focal length changes
5. Click and stops design; there are clicks and stops as you pass through the marked zoom levels; easy to use even in the dark
6. Zoom ring moves smoothly; the zoom is smooth and gradual as you twist the eyepiece; it is very hand-friendly
7. 6-element of 4-group lens structure; fully multi-coated optics for remarkable sharpness; contrast and color correction