A quick question: Not so many years ago the Abbe-König roof prism was said to be superior in transmission and contrast to the Schmidt roof prism (leaving aside for the moment special cases like the oversized Schmidt of the angled Nikon Fieldscopes). The reason given was that the Abbe-König didn't need any mirror coating.
Is this still true now that Schmidt prisms usually have dielectric coatings instead of silver coatings? Or do the Abbe-König prism still have an inbuilt advantage?
Hermann
Hermann,
I have not seen a recent discussion of this. I do remember a few years back where the comparison was made, in terms of light transmission, between the Zeiss FL 32 mm models(dielectric Schmidt-Pechan) and the Abbe Koenig of the 42 mm models. I do belief Zeiss was quoted in saying that they were able to get the 32 mm within one or two percentage points of the 42 mm models but have heard nothing since. I would "assume" that since there hasn't been a discussion since then, then nothing has changed...even with the newer Ultravid HD and Swarovision models.
Good question! I wondered about that myself.
If you don't take issue with the allbino boyz methodology like Henry, and you look at their transmission numbers for the Big Three's 10x42s and the 10x42 EDG (which isn't translated, but someone posted a link to the Polish version and I googlfished it), the Zeiss still comes out ahead in light transmission, nearly matching the venerable 10x42 SE (96% vs. Zeiss FL @ 95.5%). The Leica and EDG fall behind with 89%, but the Swaro EL (and this was pre-SV) came close with 94%.
This doesn't necessarily mean the Zeiss beats the other roofs because of the prisms since other factors contribute to transmission values.
Here's a link to the Swaro EL review, you can link to the other reviews from there:
http://www.allbinos.com/144-binocul...L_10x42_WB.html
But it is a sobering thought that the 10x42 SE, which was first produced in the 20th century circa 1995, still beats out today's "lastest and greatest" roof prism binoculars in terms of light transmission. It shows how much time and effort (and let's not forget money!) it took to make roofs as bright as porros.
Brock