SVBONYSV135 Zoom Eyepiece, Zoom 7 to 21mm 1.25 Inch Telescope Eyepiece, 6 Element 4 Group Telescope Accessories for Astronomic Telescopes Visual

The zoom has the following good points: Low scatter, high contrast, sharp to the edge at all focal lengths at f7.5, extremely good flare control, fairly good eye relief (not quite enough for glasses wearers), and smooth zooming. What's not to like?Well... A fairly narrow field of view at 21mm, and not all that wide at 7mm. Still, this is wider than the sometimes cheaper, narrower angle, 7-21mm sold by some other dealers, and the wider field is better corrected. You can't see what magnification you are using in the dark without using a light. This is where zooms with click stops come in handy. Even with a light, comparisons with fixed eyepieces show that the focal lengths marked on the barrel are longer than what the eyepiece provides by a significant margin, at least in the middle marks. Hence, you are using significantly more magnification than you might believe.That said, I use this over the much more expensive Baader zoom. The optical quality of the Svbony is matched by the viewing comfort. Here is the obligatory, "I have Takahashi and Baader orthos, but I use this zoom for my planetary viewing." I paid $50. What I got was a high performance eyepiece that I can comfortably sit and look through for hours.

This is a really great eyepiece despite its comparatively low price...makes me question the value of my $400 eyepieces, especially when you combine it with a 2x Barlow companion.I recommend using this eyepiece for quick observations, when touring the night sky with guests, or for use at public star parties. It's also an effective gift for friends and family who are just getting into the astronomy hobby.

While this eyepiece isn't without fault, I think it represents a good value all the same.Pros:Field of view is goodEye relief is very goodCons:Has some chromatic aberrationSome zoom levels perform better than others (12mm seems the sweet spot to me)Not parfocalThe eyepiece is constructed of plastic, with glass lenses. It feels mostly well made (there is some loose fit and finish, as there is a small bit of rattle--it seems to be coming from the zoom ring).This eyepiece won't perform as well as a set of prime eyepieces (single focal length), but it's versatile in that you can just twist the zoom to change magnification. Unfortunately you have to refocus after doing so as it is not parfocal.Overall, I think it's a good eyepiece for the money given how versatile it is, and how wide the FoV is (especially at 7mm).

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 eyepieces.Solid weight so it doesn't feel cheap, and very smooth movement when you twist to zoom.It comes with two rubber dust caps that fit nice and snug without being difficult to remove.Views through the eyepiece are sharp and clear, the only downside is you will need to adjust your telescope focuser slightly. There is also some reduction in field of view (i.e. how much of your target will fit in the eyepiece), but that isn't an issue.I have a few different products from SVBONY, and I am always impressed with their quality. If you are on a smaller budget, I highly recommend this zoom eyepiece.

Great addition for beginner astronomer. I was always losing the target when changing eyepieces. This allows me to zoom from 35x magnification for 100 x magnification with my 700mm inexpensive refractor telescope. This would be a great addition for kids learning . The light loss as mag increases is expected. The eye relief is great, even at the 7mm zoom. Well built zoom eyepiece at a reasonable price.

I love this piece! Glad I pulled the trigger after comparing to others for hours. Good bang for your buck

This lense was purchased for a 650/130 f5 reflector telescope and it resides under Bortle 9 skies. Without enhancements that would give my scope a range of magnification 30x-92x. With my 2x barlow the range increases to approximatel 61x-185x.What I like about this zoom is that I did not see any kidney beans along the edges. The view was clear from edge to edge.I viewed a full moon at it's lowest magnification. Craters and mountain ranges at it's highest. Everything was crisp, clear, and bright. The contrast in this lense was pleasurable to my eye.Jupiter and Saturn are absolutely fascinating at 185x (7mm setting with 2x barlow) I personally don't think I'd want to magnify them much higher than that with this partiular telescope. They move across the viewing glass too quickly and I haven't mastered keeping up at this rate yet.What I did not like about this lense was the view of the Pleiads. With this particular combination I have to utilize the stock 25mm lense in order to view the sisters as a group. I lose about 5-10% of the cluster within the zoom's narrow field.I do not regret making this purchase. It's a keeper and I would recommend this to an amateur like myself who wants to enjoy the view.To someone who's looking for a lense they can see through without poking out an eye.To a newb who's not sure what they want in a single lense kit.To someone that has a kit they wouldn't trust with casual viewers.As for me. I can see up there, and I can see up there clearly.

Any consideration of an eyepiece has to bring into account the price. With that understanding this is a very good value in my opinion. The eyepiece feels quality, Zoom is very smooth, very little refocusing, overall I think it's a very good value.