Question on prisms in scopes... (1 Viewer)

I looked at my 80mm Pentax scope and wondered what kind of prism it had - roof or porro? The specs say "porro" but that only prompted the question - do all (most) scopes use porros? If so, why? If not, why? If roofs are ever used, are they AK or SP... and, again, why? Anyone...? Thanks in advance.. Mike

Probably better to post in the general scope forum where more people (e.g. Henry) are likely to see it..

The 80mm Pentax uses Porro in the straight version, Porro followed by semi-pentaprism in the angled version. That's typical of mid to low priced scopes.

There have been a few discussions about prism types in scopes here. I'll see if I can find one and post a link.

Just to get things rolling I will say that among the alpha scopes Swarovski and Kowa still use Porros in the straight versions. Nikon uses Porro in the older Fieldscopes, but like Zeiss and Leica it uses SP Roof in the straight EDG scopes. All the alphas currently use Schmidt prisms in the angled versions. I've only seen one scope that used an AK roof prism. It was an older version of the Swarovski draw tube scope.

See this webpage:

http://www.tecplusplus.de/ManualLu/prisms.htm

rmel66.

Dear all,
Swarovski has used Amici roof prisms in its ATX, ATS and ATM telescopes, as already mentioned in earlier discussions.
Gijs