Fathoming difference between GSO superviews.

[Stonius]

For various reasons I have 2 x 30mm GSO superviews. One is the Bintel rebranded one, and the other is straight up GSO that is likely the older of the two.

The GSO one is about an inch longer than the Bintel one, and requires a lot more backfocus. If a Pentax XW20mm is the standard, this one needs about 19 - 20mm backfocus.

I wonder if it's an earlier design or something? It says right on the barrel 'GSO Superview 30mm Wide view Five Elements'.

The Bintel one says 'Bintel 30mm Wide View 5 Elements Fully Multicoated <Taiwan>'.

Markus

[glend]

Why is the 20mm Pentax any sort of standard for 30mm EPs? Just sell one of the 30mms then you don't have to think about this stuff in the middle of the night.

[Stonius]

I'd just come in. And it's because of this thread (http://www.iceinspace.com.au/forum/showthread.php?t=146347) which has quite a comprehensive comparison list in which the pentax 20mm is considered to be 0 and others relative to that. WithWithout owning the same scope as the OP it's the only comparison that means anything globally.

[MortonH]

They might have adjusted the design, which required it to be longer and a different focal point.

Do they perform differently?

[Stonius]

Edit; this post was supposed to be in reply to another thread, so I've taken it down.

[Bart]

:lol::lol::lol:

[ab1963]

The present Bintel & Gso versions are identical so the Gso you have has to be a older version ,So there must have been improvements made for whatever reason and is a perfectly acceptable question to ask and should not be made fun of for asking it but helped where possible ,i would contact either supplier and ask the question

[Stonius]

Oh, I'm not too bothered, it was just a glib comment. But I am curious, so I did contact the manufacturer, though I don't like my chances being a Chinese company with very basic english web-site.

In answer to another poster



I can't tell, because it sits about 1mm outside of focus on my 8" scope, so I can't compare. I'll try it on my 16", but from memory I think it had similar issues.