Roof or Porro prism?

John Gryphon

Well-Known Member
I was very surprised to read of Leica using the Porro prism design in these bino`s.



Swarovski EL O-Range 10x42 W B Vs. Leica Geovid 10x42 HD-B - Hunting Binoculars Blog

A bit more on it below.

Binoculars are like any other product in the sense that you get what you pay for. Don’t expect cheaper binoculars to be everything that more expensive binoculars are, but don’t assume you have to buy the most expensive pair of binoculars in order to get what you want. There a few things you need to know to start shopping so you’ll know what you are buying. Let’s look at the two most common types of binoculars.

Porro-vs-Roof-Binoculars.png




Porro prism binoculars are the classic design that we’ve seen in World War II movies and in just as many Safari movies. If you’ve never seen them there, then just know that they are the ones that have a wide hinge between the oculars. That’s a nice feature if you need to adjust them for the size of your face. Porros are more common because they are usually cheaper than Roof binoculars.

Porro prism binoculars are usually not waterproof and are typically less durable than roof binoculars. But don’t judge them as inferior, they are simply built for a price. If you live where there’s a great view of nature from your balcony, or perhaps the city below and you simply want to admire things from the comfort of your deck chair, a pair of Porros will satisfy you just fine and you’ll save some money. Larger Porros are better if you want to look at birds or small objects at a distance.

Roof Binoculars have a narrow hinge tween the oculars and they look like a large letter H. These binoculars are for the more serious user who wants to get out and get dirty. If you are traveling with your binoculars, roof binoculars will be a better choice than Porro prism binoculars because they are designed to be a lot more durable and are usually waterproof.

Roof binoculars are in a higher general price category than Porro prism binoculars and represent a class of more-powerful viewing instruments. If you seek to buy roof binoculars, be prepared to spend more money. They may be overkill if you are just a recreational user who is looking at cool things from your deck chair.
It is the physical size of the binocular and magnification specs that dictate how much you can see. If you’re just looking at the trees from the deck (and not spying on your neighbours!), Porros may be all you need. If you decide that you want more powerful binoculars and that is your priority then skip looking at Porros and start looking at Roof binoculars.
 
Everyday a school day. Thank you for posting that. My father's binoculars in WWII were big 7x50 porro prism. Then there's all sorts of stuff about types of glass and what "system" of roof prism is used? It just baffles me. So thank you for the explanation.
 
What a biased view and use of language. Belittling the Porro prisms because they are less powerful and less durable? What has build quality, magnification and Objective size/light gathering to do with the light path/prism design?

Porro prism design has superior optical performance. With the simpler light path and better inherent light transmission through fewer reflections it is easier to achieve a comparable quality image with less production cost. Porros require fewer expensive coatings to reduce the light spill at every reflection in the Roof prisms. The fact that the Porro design is so good that they can give you a great image at less cost than the roof prism design doesn't mean.... because they cost less to produce they are any worse at their job...that's marketing speak appealing to pure snobbery.

Roof prism binoculars can have advantages like smaller size and the ease of waterproofing, but power and durability are not down to the prism design.

The Porros I use however are nitrogen filled/waterproof. I much prefer the enhanced 3D view you get from the wider spaced Objective lenses which I think helps to separate an animal from its background. But hey I am "just a recreational user" to be sneered at by a marketing man.

Alan
 
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I think you win the 2018 "Put Down By The Facts" award Alan :)
Not too over the top I hope!

Just grates that every aspirational association in the article is negative for the one and positive for the other...if you are the cheapskate slob in the deck chair peeping at your neighbours, Porros are good enough for your sort...but if you are the power user / travelling / adventurer then only Roofs will do...


There we go... from the same manufacturer light transmission in their Habicht Porros 96% and only 91% in the Roof SLCs costing twice the amount, 90% in the Roof Els at three times the cost.

Alan
 
KB! Thanks! I had no idea that I could buy waterproof 7x42 in a "first rank" maker (and not Zeiss's "milk bottles") one made by other than Leica. Maybe Swarovski should advertise those 7x42 items more widely. If I had known I'd have looked for these instead of the Leica's I've presently got.
 
The Minolta Activa WPs I have are "second rank" but the image is well matched to my Swarovski Z4i with the added advantage of enhanced 3D.

Sadly no longer made, but every time I see them on eBay or Amazon market I pick them up. I have 4 pairs now, one in each car and one in the house...on the basis that I am better off with a second rank set of binoculars to hand, than a first rank set far away at home in a safe place. Also means I never forget them when going stalking.

Alan
 
KB! Thanks! I had no idea that I could buy waterproof 7x42 in a "first rank" maker (and not Zeiss's "milk bottles") one made by other than Leica. Maybe Swarovski should advertise those 7x42 items more widely. If I had known I'd have looked for these instead of the Leica's I've presently got.
They will certainly withstand a shower!

"Submersion Tightness:
13ft/4m Water Depth (inert gas filling)"

K
 
So porro binos are inferior?

Does this mean my recently refurbished (now ‘as new’ for a very reasonable price by the factory) Swarovski SL 8x56s are only fit for the car boot sale? Didn’t realise they weren’t waterproof as well? In that case maybe Swarovski could have saved a bit by not marketing a hi-viz marine version and the optional floatation neck strap!

Heavy yes, but superb optics, ergos and build quality.

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I really enjoy my porro prism Swarovski Habicht 10x40 W GA binos (with the green rubber armoring).

I find the 3D view through this good quality glass outstanding. They are good enough for my needs in low light (though probably not as good as the specialized 8x56 above), and I find them relatively light. They are also easy to hold and use with one hand when stalking, which is something I like.

The only thing I would improve are the eye pieces. Due to the short eye relief (13 mm), the eyes make the outside surface of the eye lenses fog up in very cold weather. Don't know why Swarovski has never improved that, when these binoculars have been around for so long and are still made...
 
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