Svbony 6mm UW 68°

[cajen2]

I bought this some months ago as a stopgap till I could afford what I thought would be better-quality glass. It was hardly ever used as FLO did the Pentax sale and I took the opportunity to get myself a 5mm XW. Who'd use a Svbony when you've got a Pentax, right? Well, tonight, I was viewing parts of M42 with the Pentax and decided I wanted just slightly lower mag. So I put the Svbony in the focuser and was amazed at just how good the little EP was (it's about a quarter of the size and weight of the Pentax). The image was crisp and to be honest, hardly any worse than an EP five + times the price. The eye relief was very slightly shorter and the very edge of field slightly less controlled but that was it!

So the upshot is, if you're looking for a very cheap but good quality EP as an (even cheaper) alternative to a BST Starguider, you could do a lot worse than this Svbony. Do check models, though, as the company makes a huge range of EPs of varying quality.

[Mr Spock]

Svbony do seem to be turning out decent stuff at affordable prices. We could do with some side by side tests to determine just how good they are though.

[cajen2]

I also have a BST Starguider 8mm and the Svbony is at least as good as that.

[Louis D]

I really like the 20mm version in my Barlowed binoviewer, but it isn't very good at f/6.

How is the exit pupil behavior of the 6mm?  I've read that the 6mm and 9mm versions suffer from kidney beaning (SAEP) which requires careful eye placement.

[cajen2]

Interesting. My scope's also f/6, but no problems with exit pupil or SAEP. Eye placement is important to the view of course at these magnifications but that's true of most EPs.

It's quite possible of course that the manufacturer has done a better job with this f/l.

[Don Pensack]

18 hours ago, cajen2 said:

I bought this some months ago as a stopgap till I could afford what I thought would be better-quality glass. It was hardly ever used as FLO did the Pentax sale and I took the opportunity to get myself a 5mm XW. Who'd use a Svbony when you've got a Pentax, right? Well, tonight, I was viewing parts of M42 with the Pentax and decided I wanted just slightly lower mag. So I put the Svbony in the focuser and was amazed at just how good the little EP was (it's about a quarter of the size and weight of the Pentax). The image was crisp and to be honest, hardly any worse than an EP five + times the price. The eye relief was very slightly shorter and the very edge of field slightly less controlled but that was it!

So the upshot is, if you're looking for a very cheap but good quality EP as an (even cheaper) alternative to a BST Starguider, you could do a lot worse than this Svbony. Do check models, though, as the company makes a huge range of EPs of varying quality.

I don't think Svbony is a manufacturer, but just a reseller of already existent Chinese products under private label.  Most of their products were available years before the Svbony label (which was formerly Vite).

But, you put your finger on the differences between inexpensive eyepieces and expensive ones:

Expensive eyepieces will have better corrected outer fields, both in terms of chromatic aberration and astigmatism, may have wider fields on top of that, and better control of light scatter on bright objects.

If all you're doing is looking at the center of the field, there is very little difference between eyepieces.

[cajen2]

1 minute ago, Don Pensack said:

I don't think Svbony is a manufacturer, but just a reseller of already existent Chinese products under private label.  Most of their products were available years before the Svbony label (which was formerly Vite).

But, you put your finger on the differences between inexpensive eyepieces and expensive ones:

Expensive eyepieces will have better corrected outer fields, both in terms of chromatic aberration and astigmatism, may have wider fields on top of that, and better control of light scatter on bright objects.

If all you're doing is looking at the center of the field, there is very little difference between eyepieces.

Yes, indeed, though as I said, the outer field of view is fine. You only notice a very small difference if compared with an EP over five times the price.