Do 7x/8.5x SLC/ EL have Abbe Koenig or Schmidt Pechan prisms? (1 Viewer)

I have been thinking of getting the Swaro 7x42 SLC, mainly because the discontinued Zeiss Classics are very hard to find in this size now!

Looking carefully at the technical specs of the 7x42 & 10x42 SLC's, they appear to have differences that aren't simply the result of the magnification: the 7x are 10mm longer and 80g heavier than their 10x counterparts.

The EL range have similar differences: the 8.5's are heavier and longer than the 10's.

The same trend isn't there with 42mm Leica Ultravids and the 42mm Zeiss Victory range (but the 42mm Victory with A-K prisms is significantly longer than the 32mm with S-P prisms).

I know that A-K prisms are longer than S-P, does anyone know if that may be why the lower magnification 42 mm Swaros are longer than the 10x? I guess the Zeiss Classics are what made me wonder, the 7x42 & 8x56 being A-K, the 10x40 and 8x30 being S-P.

Also, the lucky owners of the 7x42 SLC's seem to describe them in much the same way as those that use the Zeiss 7x42B G/AT Classics......I know the simple answer if I want the inherent advantages of A-K in a 7x42 is to get the Zeiss Victory, but they are really ugly (IMHO!).

Cheers, Tom

Tom,

The short answer is no, all the Swarovski's use Schmidt-Pechan prisms.

Binocular length doesn't always work as a predictor of effective objective focal length in the current roof prism binoculars that use focusing elements, which may be negative like Barlows (Leica, Zeiss) or positive like focal reducers (Swarovski).

Henry

Hi Don!

I have the SLCnew 7x42B, but have no idéa about the kind of prisms in it.
About the technical specs of the 7x42 & 10x42 SLC's the less weight and length of 10x version surely is simply caused by the shorter focallength of eyepieces with 10x than with 7x.
This relation you can also notice in the comparison between usual 7x50 and 10x50 porro binoculars of same brand and serie. Because the objective lenses in these models, as in the SLC's, are the same, the difference of magnification will be a result of the different focallength of eyepieces.

Shorter focal length means smaller and lighter lenses and therefore 10x versions are as well slightly shorter and lighter. Also there is a direct relation between eyepiece focallength and eye relief; higher magnification= shorter focallength=shorter eye relief. The 7x versions has always better eye relief than 10x version.
If you study astronomical eyepieces of the same construction with different focallengths this relation is very obvious.

Regards, Patric

Hi Henry & Patric,

Thank you for the superfast replies! I should have thought of the eyepieces in this respect, I see I will have to do some more study on the differing focusing elements. I think I need to look harder to find shops with binoculars to compare, as how they feel for me should always be the deciding factor.

I have decided to look for 7x42's of some sort: being relatively solidly built, I don't usually notice extra weight in binoculars. Also I am in no rush, a purchase of this kind usually takes me a couple of years! So I'll be poking my nose into as many stores as possible for a while until I find the 7x42 that "just feels sweet".

Cheers, Tom