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.

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.

This is a fine eyepiece especially when you're with the general public in the field. When you need to find an object, center it, then zoom in, it's perfect especially with planetary objects like the moon. You don't need to swap out eyepieces in the dark. This eyepiece matches the best zoom eyepiece that Orion Telescopes sold before they went out of business for 1/2 the price. Good clear views at all powers and great eye relief. A great buy!

Great product that is very well made! Great value for the price!

I think this may be the best thing I’ve done for my telescope. I love the 7mm setting. The moon is extremely sharp and fills the eyepiece. Changing the zoom is smooth and brilliant. I have a Dianfan 650/150.Six stars