One of the problems is that SVbony has 3 SV135. Why they do this I don't know. I have SV135 40-57, this is the one Ernst reviewed. I do not have the other 2 SV135. I do however have all of the other zooms that SVBony markets. 3-8. 10-30, 9-27, 7-21, 8-24 super zoom. I like them very much especially for the price point. What I have found is that some of the eps work better in different OTA than in others. I am not sure of the correlation of why. I am in the process of investigating this funny phenomenon. It is funny because at this point it seems inconsistent, that is why I am embarking on the project. I say inconsistent because I have confused which ones seem to do it in which OTAs. The reason this occurred to me was that the other night I picked up one of my zooms and put it into the diagonal and it didn't look right. It seemed to be a little bit softer than I remember it looking. I put in another of my SVbony zooms in and it looked good. I stuck the ep in question into the diagonal of another members OTA, which was a different aperture and optical design and it looked good.
I primarily use the zooms for outreach, getting an idea of sky conditions and for my grab and go.set ups for their convenience. The 3-8 and 7-21 (40-57) I think are the best of the line. I just received the 8-24 Super Zoom and have not taken it out for first light. If this phenomenon is actually something with different OTAs than it is the first fault I have found with the SVbony line of zooms. I am sure there are some that can pick them apart. But, on the whole I find their products pretty good and in some cases fantastic. I sat on the fence for a quite awhile about the $300 they want for the 8-24 Super Zoom. I hope that I am not disappointed it would the first time for a SVbony product.
Never Lose the Wonder,
RF