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best bins ? (1 Viewer)

henry link said:
mak, Thanks for the information. The exact percentage difference is something I had not been able to track down. Can you tell me if this difference refers to silver or aluminum coating and how many reflecting surfaces of a Schmidt-Pechan require mirror coating? Henry

The latest coatings reduce the amount of light loss on the reflecting surface (mirror) of the prism. Perhaps Henry it should be added that the figures you gave earlier of 85%-90% is the total light transmission through the entire binocular, and not just through the prism system. This takes into account glass to air surfaces, as well as the prism.
 
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A quick calculation from an amateur (me..=) could look like this: Leica claims 99,5% reflection in every surface of the prism elements. Assume the same for transmission. Number of lens elements varies between 8 to 11 in the ultravid series. Lets say 9. Number of transmissions glass/air should then be 9x2 = 18. Plus 5 reflections in the prism makes 23. 0,995 ^ 23 makes 0,89. So about 89 percent of the light is tramitted.
 
Does anyone have a view on Minox 8x32? They were bought for me as a present and I just can't get on with them but can't pin down why exactly. I read a review which praised them, but can't vouch for the reviewers expertise/ objectivity.
 
gorank said:
A quick calculation from an amateur (me..=) could look like this: Leica claims 99,5% reflection in every surface of the prism elements. Assume the same for transmission. Number of lens elements varies between 8 to 11 in the ultravid series. Lets say 9. Number of transmissions glass/air should then be 9x2 = 18. Plus 5 reflections in the prism makes 23. 0,995 ^ 23 makes 0,89. So about 89 percent of the light is tramitted.

Another calculation from an amateur. I think Leica and others are claiming 99.75% for lens coatings,99.5 for mirror coatings. Another wild card in this is light lost in travelling through glass. An old figure I've seen is 1% per inch of glass. In most binoculars light travels through about 5 inches (127mm), most of it in the prism. Is the most recent glass better than this?
 
Darrenom said:
Does anyone have a view on Minox 8x32? They were bought for me as a present and I just can't get on with them but can't pin down why exactly. I read a review which praised them, but can't vouch for the reviewers expertise/ objectivity.

Nope, not a make you see about much over here. Goes to prove though that bins are something you really need to try for yourself.
 
Darren Minox have been around for a while,Looked at some of their binoculars a the Rutland bird fair last year and considered them very goodfor the money.Also saw a review of Minox but cant remember the model but it got a good review.Dont you like the image or is it the feel of them that bothers you .
 
New Victory's

henry link said:
If you are planning to buy a cost-no-object binocular I would wait to see the new Zeiss FL Victories which are due out in May.
If done properly they should be a genuine advancement over the current generation of roof prism binoculars. The use of fluorite in the objective should noticeably increase contrast. The Abbe-Koening roof prism currently used by Zeiss in the Victories and some of the old Classics has inherently higher light transmission than the Schmitt-Pechan prism used by Leica, Swarovski, Nikon and everybody else; and Zeiss claims to be employing a new eyepiece design with edge sharpness superior to any they have used before. All of that appears to be combined in a new mechanical design with improved ergonomics.
A completely successfull optical design, however, would still probably only equal, but not surpass the optics of the Nikon SE series porros. Why won't Nikon do the birding world a favor and redesign the 8x32SE as a waterproof reverse porro with screw down eyecups? That would be a binocular!
Hello Henry. I was going to send this message this morning while at work, but I got too busy.
Can I go to Zeiss.com, or somewhere, to see those new Victories you mentioned? I don't suppose those are the Victory II's, are they?
 
marcus said:
Hello Henry. I was going to send this message this morning while at work, but I got too busy.
Can I go to Zeiss.com, or somewhere, to see those new Victories you mentioned? I don't suppose those are the Victory II's, are they?

Marcus, The new ones are called Victory FL. Just go to the top of the binocular forum here. There's a thread in the Zeiss section. Nothing at Zeiss.com the last time I checked. You can get information about them by phone from Zeiss-USA. Henry
 
Thank you, Henry for some very informed and interesting comments.

I'd be grateful if you could clear up a couple of points:-
"If you are planning to buy a cost-no-object binocular I would wait to see the new Zeiss FL Victories which are due out in May"
- is there any info on the web about this new design?

"The Abbe-Koening roof prism currently used by Zeiss in the Victories and some of the old Classics has inherently higher light transmission than the Schmitt-Pechan prism used by Leica, Swarovski, Nikon and everybody else"
- interesting, but if this design is so clearly better, why doesn't everyone use it?

"Why won't Nikon do the birding world a favor and redesign the 8x32SE as a waterproof reverse porro with screw down eyecups? That would be a binocular!"
- as a Nikon 8x32 SE user you don't have to convince me that it's a great instrument. I'd agree re: redesigned eyecups and waterproofing (though mine have never leaked) plus I'd prefer a barrel style focus wheel. But reverse porro? Why? The current design is the most comfortable porro design I've ever used. What advantage would a reverse porro have?
John
 
The Nikon is 'showerproof', I think - whatever that means. I keep on the look oit for a s/h pair or, even better, a pair of Superior Es.
 
John Cantelo said:
Thank you, Henry for some very informed and interesting comments.

I'd be grateful if you could clear up a couple of points:-
"If you are planning to buy a cost-no-object binocular I would wait to see the new Zeiss FL Victories which are due out in May"
- is there any info on the web about this new design?

"The Abbe-Koening roof prism currently used by Zeiss in the Victories and some of the old Classics has inherently higher light transmission than the Schmitt-Pechan prism used by Leica, Swarovski, Nikon and everybody else"
- interesting, but if this design is so clearly better, why doesn't everyone use it?

"Why won't Nikon do the birding world a favor and redesign the 8x32SE as a waterproof reverse porro with screw down eyecups? That would be a binocular!"
- as a Nikon 8x32 SE user you don't have to convince me that it's a great instrument. I'd agree re: redesigned eyecups and waterproofing (though mine have never leaked) plus I'd prefer a barrel style focus wheel. But reverse porro? Why? The current design is the most comfortable porro design I've ever used. What advantage would a reverse porro have?
John
John, Excellent questions. I’ll be happy to climb on the soap box and try to answer them. I guess it’s obvious I’m an iconoclast about some of this, and an obsessive to boot
(my wife wishes binoculars had never been invented), so bear with me. Maybe I can stimulate some discussion.
I think the Abbe-Koenig prism has been used so seldom because it has one serious disadvantage in binoculars. It’s a long narrow prism configuration, with a light path that doesn’t reduce the length between the objective and the eyepiece very much compared to just a hollow tube, Some of the old Hensoldts using AK prisms look to be a foot long. Porro and Pechan prisms have light paths that absorb more length, so binoculars using them will always be shorter than those using AK, if the focal length of the objectives are equal. You’ve probably noticed that the Zeiss 7x42 Dialyt, which uses AK prisms, is an unusually long binocular for it’s aperture. I think it would be even longer if a typical F:4 objective had been used. To make it as short as it is, the focal ratio was probably dropped to some figure below F:4
At the other end of the size scale not even Zeiss uses AK prisms in really small binoculars, possibly because there just isn’t enough space between the objective and the eyepiece in such a short focal length binocular for an AK prism of the size required to handle the light cone.
In the current Victory Zeiss attempted to make a binocular using an AKprism just as short and compact as one using a Pechan. To do that the focal length of the objective had to drop even more than in the Dialyt,with the focal ratio probably approaching F:3, necessitating the use of a complex objective and eyepiece to try to achieve a reasonable degree of correction of aberrations (which get worse the lower the focal ratio). Most people seem to agree that the result, except for light transmission and contrast, was not a complete success.
On paper the new binocular looks like a contender. It’s addressing the weaknesses in the current design with a Fluorite objective, improved eyepiece and judging from the dimensions, an increase in focal length.

Now on to reverse porros, a sadly underutilized design in high end binoculars. So far the design has been confined mostly to small inexpensive bins, but it could work with 32mm objectives, or even larger with a more vertical offset between eyepiece and objective. The Bushnell 8x30 Nature View, The Bausch&Lomb 8X50 Elite, and the old Rollei 7x42 hint at the potential.
Reverse porro bins have the same advantages over traditional porros that roof prisms have. First of all, because of the close spacing of the objectives they have the same illusion of higher magnification compared to traditional porros that people like so much in roof prisms .
Second and more important for birders, the close spacing of the objectives allows for much better merging of the left and right fields at close distances. Try comparing the view through a traditional porro and a roof or reverse porro at 3 meters. The two fields in the traditional porro will show only a small area of overlap, a bit like the cliche movie version of a binocular view, two slightly overlapping circles. The roof and reverse porro will show much better merging, closer to a single circle, allowing both eyes to come closer to the ideal of looking straight through the center of the field. The effect gradually diminishes with distance so that at long range all three types show something close to a single circle.
Finally reverse porros have the same advantages over roof prisms that traditional porros have. Lower cost and all other things being equal, higher optical quality. If the optics of the Nikon 8x32 SE were placed in an ergonomically sucessfull reverse porro housing (something hand-friendly we haven’t seen yet in a reverse porro ) the result would be a binocular with the things we like about viewing through roof prisms combined with the advantages of porro prisms in the same binocular.
 
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Henry, your elaborations are extremely interesting. Tell your wife that you are doing a lot of good with this, so maybe she'll be a bit more tolerant.

Now, one point that I think speaks against reverse porro constructions: As the objectives are closer together one is bound to lose a major portion of the 3-D effect that is better in porros than in the other types. I would assume that reverse porros must be worse than roofs in this respect.
 
Swissboy, Thanks for the kind message. I’ll pass it along to my wife for whatever good it will do.
The 3-D effect you mention is, I suppose, one of those areas that makes life interesting. We all see the same two things but differ about which is preferable.
I can’t see any actual optical advantage coming from the “enhanced” 3-D effect of traditional porros. At closest focus, it results in the definite optical disadvantage of forcing one eye or both to move farther away from the center of the field, compared to roof or reverse porro. Enhanced 3-D as an advantage strikes me as one of those items of conventional wisdom that gets passed along until finally no one questions it’s basis anymore.
In any case, the 3-D effect is not completely absent in reverse porro. A reverse porro with 32mm objectives might have about 40mm separating the centers of the objectives. For my eyes roof has 60mm, and a 32mm trraditional porro about 120mm, so a reverse porro at 3m would show about the same 3-D effect as roof at 4.5m and traditional porro at 9m. You don’t hear users of traditional porros complaining that the images at 9m are too flat. Henry
 
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henry link said:
Swissboy, Thanks for the kind message. I’ll pass it along to my wife for whatever good it will do.
The 3-D effect you mention is, I suppose, one of those areas that makes life interesting. We all see the same two things but differ about which is preferable.
I can’t see any actual optical advantage coming from the “enhanced” 3-D effect of traditional porros. At closest focus, it results in the definite optical disadvantage of forcing one eye or both to move farther away from the center of the field, compared to roof or reverse porro. Enhanced 3-D as an advantage strikes me as one of those items of conventional wisdom that gets passed along until finally no one questions it’s basis anymore.
In any case, the 3-D effect is not completely absent in reverse porro. A reverse porro with 32mm objectives might have about 40mm separating the centers of the objectives. For my eyes roof has 60mm, and a 32mm trraditional porro about 120mm, so a reverse porro at 3m would show about the same 3-D effect as roof at 4.5m and traditional porro at 9m. You don’t hear users of traditional porros complaining that the images at 9m are too flat. Henry

Henry, thanks for clarifying this aspect. Come to think of it, the 3-D effect would probably also suffer in any kind of type from the fact that sharp focussing is in a narrow zone only. Robert (Swissboy)
 
henry link said:
A completely successfull optical design, however, would still probably only equal, but not surpass the optics of the Nikon SE series porros. Why won't Nikon do the birding world a favor and redesign the 8x32SE as a waterproof reverse porro with screw down eyecups? That would be a binocular!

Screw in screw out eye tubes would indeed be nice.

Unfortunately the Nikon 8x32 SE are focussed by moving the eyepieces in and out relative to the prism housing. This means that the internal volume changes, and hence they cannot be nitrogen purged and waterproof. (Incidentally this is also true of the Zeiss 7x42 BGAT.)

Most roof prism binoculars are focussed by moving a small lens that sits between the objective and the prism. This internal focussing mechanism means that the volume is constant, and hence they can be purged and effectively sealed.

Quite why internal focussing cannot be applied to porro prism binoculars I know not. Maybe it would have a detrimental effect on the optical quality?
 
Leif, Apparently it is possible to waterproof and nitrogen purge CF porros. Two examples would be the Nikon Mountaineer and the Swarovski Habicht. There was an old Kern 7x50 porro that used internal focus. Like you I wonder why others haven't used it. Henry
 
Thanks, Pete - those extra ten or so years take a toll on the memory cells like no previous ten years ever did.
 
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