Two Leica questions (1 Viewer)

Question one: I am assuming that the Trinovid BNs are still produced. They are still listed at most online retailers and are still featured at Leica.com. Am I correct that they are still being made or is there quite a bit of stock still available?

Question two: Regarding the focus range of BNs and Ultravids, it is said that to make the BA into the BN Leica shifted the focus range and in doing such lost some focus near infinity. Is it possible to use a BN for astronomy or is the focus range too limited on the far end? Is the focus range similarly limited in the Ultravids?

Gracias.

Two questions answered

The BN is absolutely still made. There is no shortage of them.
I have a pair of 12x50 BN I was using to look at a full moon a few weeks ago, as well as some stars. I was able to perfectly focus the binos, but did notice that the focus wheel was close to its limit. I suppose if you had poor eyesight, you might run out of focus room.

Robert Ellis said:

Question two: Regarding the focus range of BNs and Ultravids, it is said that to make the BA into the BN Leica shifted the focus range and in doing such lost some focus near infinity. Is it possible to use a BN for astronomy or is the focus range too limited on the far end? Is the focus range similarly limited in the Ultravids?

Gracias.

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Robert, I had a pair of Leica 8x32BN's and on my particular pair the focus wheel came to an abrupt stop when things seemed to be focused at infinity. There was absolutely no over-focus past infinity. I recall looking at some stars and they were sharp, and this never really presented any practical problems, but it always kind of bothered me for some reason and I ended up selling them. I did not notice this severe restriction on far focus looking through some Ultravids recently.

Robert
Regarding the focus of the Bn's and the Ultravids. I have Ba's and a very marked difference in dioptre balance. When adjusting these there is no restriction on close to infinity travel but on the BN's and Ultravids there is a marked loss of travel. So much so that is is impossible to get infinity!
Ivan

I have no problems viewing the stars or the moon with my 12x50 BNs, but yes, there is not really anything past infinity, even with the diopter set to 0. If you have to make any noticable adjustment to the diopter, infinite might not be available to you.

xenophobe said:

I have no problems viewing the stars or the moon with my 12x50 BNs, but yes, there is not really anything past infinity, even with the diopter set to 0. If you have to make any noticable adjustment to the diopter, infinite might not be available to you.

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I don't understand why we are discussing astronomical use with regard to infinity focus. Infinity focus is infinity focus, whether it is at 100 yards or 93,000,000 miles.

Jonathan B. said:

I don't understand why we are discussing astronomical use with regard to infinity focus. Infinity focus is infinity focus, whether it is at 100 yards or 93,000,000 miles.

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Infinity focus is fixed for perfect eyes, but if you are an eyeglasss wearer, and prefer to use a binocular without eyeglasses, then the amount of focus 'beyond infinity' might be of concern. I think it is for short sight - myopia - that this matters. If like me you have odd eyes (my right eye is very short sighted) then the function of the diopter is of interest.

Leif

Jonathan B. said:

I don't understand why we are discussing astronomical use with regard to infinity focus. Infinity focus is infinity focus, whether it is at 100 yards or 93,000,000 miles.

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Because it was mentioned perhaps?

Robert Ellis said:

Question two: Regarding the focus range of BNs and Ultravids, it is said that to make the BA into the BN Leica shifted the focus range and in doing such lost some focus near infinity. Is it possible to use a BN for astronomy or is the focus range too limited on the far end? Is the focus range similarly limited in the Ultravids?

Gracias.

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Robert,

I have a 10x50 Trinovid. Focussed at infinity there is still some range to focus above. Only you can find out by trying them if this is enough for you. If not, Leica is offering the service to shift focus in a way that you get more focus range above infinity for the cost of some lost of close focus range.
BTW the 10x50 Leica is still my favorite bin for astro use: pinpoint stars and a great FOV.

Steve

Jonathan B. said:

I don't understand why we are discussing astronomical use with regard to infinity focus. Infinity focus is infinity focus, whether it is at 100 yards or 93,000,000 miles.

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Greetings!

Interesting you would pick 93,000,000 miles as one set of limits...
As for me, I spend as LITTLE time looking at the SUN with my binoculars as possible!

Best wishes,
Bawko

Atomic Chicken said:

Greetings!

Interesting you would pick 93,000,000 miles as one set of limits...
As for me, I spend as LITTLE time looking at the SUN with my binoculars as possible!

Best wishes,
Bawko

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Hi, all

Well, I don't really look at the sun except by accident, but you should all know that it is often in perfect focus.

The point about an eyeglass wearer wanting to use binoculars without glasses for astronomical use is well taken.

As for Leica, my Ultravid is an example of sample variation. It performs as though it is optically perfect (per my opinion), but whereas the diopter adjustment in my other bins (including another Leica) is set correctly at "0", the Ultravid is set at +1.25. I suspect someone who needs ample positive diopter adjustment would not be able to adjust it adequately.

93,000,000 miles is, astronomically speaking, quite close. Infinity is not the best term but it is the one used, I suppose because in relation to terrestrial observing the far end of the focus is of little concern. There are plenty of binoculars that don't have a far end long enough to get crisp focus on stars.

Robert Ellis said:

93,000,000 miles is, astronomically speaking, quite close. Infinity is not the best term but it is the one used, I suppose because in relation to terrestrial observing the far end of the focus is of little concern. There are plenty of binoculars that don't have a far end long enough to get crisp focus on stars.

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Hello, all,

New guy here; I have enjoyed using binoculars for some 45 years now. I was hesitant to join yet another forum, but what the heck! I have gleaned some good info from this group. I've seen Robert come over to the CN Binocular Asto. forum and it is good to see folks realize that binoculars have a place in the world of astronomy as well as terrestrial use. Why waste half your life?? ;^)

In regards to binoculars and their ability to focus at infinity, I have never seen a binocular that couldn't. For most glasses, infinity focus extends from several hundred yards to the stars; it makes no difference after a point. If anyone who has normal vision cannot see stars in sharp focus they have a defective binocular, IMO. Of course, what is considered "sharp" varies between binoculars, the smaller the point of light the better.

I have been using binoculars for astronomy for over 30 years now. What I have noticed over the years is that in the quest for closer focusing distances, manufacturers have been taking away some of the "-" diopter range in favor of the "+" side. My old Nikon Es have a range of +10/ -5 diopters which would accomodate many who choose not to wear eyeglasses while viewing. My newer E2 glasses have quite a bit less "-" adjustment but have really close focus instead. The same applies to my newer roof glasses.

Folks like me who have hyperopia (farsightedness) have no problem focusing at infinity without eyeglasses; all you have to do is focus closer and infinity snaps right into focus. Those of you with myopia however, have very little latitude to focus without eyeglasses; that part of the focus range "beyond" infinity has been whittled away.

This is why many glasses with individual focusing eyepieces are favored by astronomers. These typically have an equal range +/- of infinity. Once focused you just leave them; there is no flexing eyepiece bridge to cause focus to move in and out. The down side is that they don't focus as close as most CF glasses and focusing is certainly not speedy.

Anyway, sorry to make such a verbose first post; you have a great forum here.

Rich V

Rich V said:

...
Folks like me who have hyperopia (farsightedness) have no problem focusing at infinity without eyeglasses; all you have to do is focus closer and infinity snaps right into focus. Those of you with myopia however, have very little latitude to focus without eyeglasses; that part of the focus range "beyond" infinity has been whittled away.

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I have myopic vision, but slight enough that I can sight a warbler by motion, no glasses needed. Seems like a generous leeway past infinity is pointless for terrestrial viewing because you would be walking blind to employ those inbuilt diopters.

In general, Leica binoculars (BN and Ultravid alike) have less negative diopter adjustment range than many other top marks. Therefore, more of the myopic users cannot reach infinity focus with them than with e.g. Nikon LX/HG's or Zeiss FL's. Myopic people should always try before they buy - even more so than the rest of us.

Kimmo

For what it's worth, I have -7.5 myopia. With a 7x42 BA, I can reach almost infinity, 110 meters, without my spectacles. With an 8x32 BN, I cannot even do that well, perhaps 35 meters. With a Nikon 8x32 SE, I can reach a little farther without my glasses. The Nikon 8x30EII, the Zeiss Victory 8x40 and 7x42 BGAT*, allow me to get to infinity.
However, with my astigmatism, I still have to use my spectacles for astronomical work with any binocular. In the daytime, my reduced pupil diameter compensates for the astigmatism. At night, my dilated pupils give me full astigmatism.

I presume that newer Leica glasses, and the newer Zeiss FL glasses favour close focus for most over general use for highly near sighted users. Anyway that is why we spectacle wearers need collapsible eyecups. I find that the Leica BN is superiour to the two Nikons in reducing reflection which enter through the ocular, when the cups are down.

Happy bird watching,
Arthur Pinewood :egghead: