I keep meaning to find an idiots guide to explain the difference (minus the physics!) in types of bins (porro/roof) and therefore why buy one sort rather than the other.
Can anyone tell me the idiots guide? with or without pictures!!
Thanks. (sorry if I've missed an faq somewhere)
Roofs are easier to waterproof - that's about all. And they're usually heavier. If you have small hands, you might prefer a roof prism design because it is less wide and more compact. But the Nikon E is a compact porroprism (http://www.acecameras.co.uk/asp/web...4/prodtype.asp) and seems to be as good a binocular as you'll get optically, yet are not fully waterproof (would it ever matter in practice, I wonder?). A similar quality waterproof roof prism would cost far more, and not necessarily be any better optically - the Nikon 8x32HG for instance is £500-00 or thereabouts.
[QUOTE=smallblueplanet]I keep meaning to find an idiots guide to explain the difference (minus the physics!) in types of bins (porro/roof) and therefore why buy one sort rather than the other.
Can anyone tell me the idiots guide? with or without pictures!!
Thanks. (sorry if I've missed an faq somewhere)[/QUOTE]
In simple terms:
Porros tend to be more bulky, each optical assembly has a dog leg shape producing a shape that some people do not like, they are cheaper to make for a given optical quality due to lower tolerances of the prisms and no mirror coatings required. They tend to use external focussing which is hard to waterproof. Because the objectives are further apart, the image has a strong 3D feel, but focussing on nearby objects can be hard. The near focus distance is often quite large. The eye tubes tend to be rubber which are inconvenient to use.
Roof prism binoculars tend to be more compact, less bulky, expensive to make due to high tolerances on the prisms, and the need for phase and mirror coatings on the prisms. They tend to use internal focussing which is easier to waterproof. Because the objectives are close, the image does not have such a strong 3D feel, but focussing on nearby objects is easier. The near focus distance is often quite small. The eye tubes tend to be screw-in screw-out which are convenient in use.
So in brief, the typical porro prism binocular is cheaper for a given optical quality, is not waterproof, does not focus very close and is somewhat bulky and thus less comfortable to hold. A typical roof prism binocular is expensive for a given optical quality, is waterproof and nitrogen filled, and is comfortable to hold. The above are generalisations and your milage may vary depending on your physiognomy e.g. the size of your hands.
I think the fashion these days tends to be for roof prism binoculars, presumably because they tend to have all the 'features' some considerable desirable: waterproof, nitrogen filled, compact and screw in screw out eye tubes.
I'm sure I've missed out important points ...