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Early Elite's (1 Viewer)

Copy, and then only in the sense of taken as a model. Because Leitz was the first company to design a compact, internal focussing roof prism binocular (series) with great quality, all subsequent roof prism binoculars are more or less modelled on the Trinovids.

Renze
 
Renze,

Do you know what changes [apart from rubbering] were made for the 2nd gen. of these bins [elites that is]? I assume phase coating but were there others?

Physically, at least the 8 x, these very closely resemble the 2nd gen Elite's .

A bit OT, I always found the performance [resolution, contrast] better in the 2nd gen. Elite's, compared to the 3rd gen. My 1990 Elite's always wowed me, the 3rd gens not so much. Anyone have experience with both?
 
Copy, and then only in the sense of taken as a model. Because Leitz was the first company to design a compact, internal focussing roof prism binocular (series) with great quality, all subsequent roof prism binoculars are more or less modelled on the Trinovids.

Renze

Did these use the Uppendahl Roof Prisms that the Leitz Binoculars used?

Bob
 
These do look very much in body structure like the old Leitz Trinovids except for the locations of the focuser and the diopter. I wonder if they used the Uppendahl roof prisms like the Leitz did? Because of the location of the Diopter ring shown on the B&L's I don't think that the Leitz eyecups would fit on them. The Browning pictured doesn't appear to have that ring.Bob

Hi Bob,

Excuse me, I overlooked your earlier post with the same question. No, I don't think there's an Uppendahl in the B&L. Inspection with a flashlight shows it to be quite different to the Leitz' so it's probably the more common Schmidt-Pechan.
I see you had your doubts about using the Trinovid's eyecups on the B&L already and yes, you're right, they're not 100% interchangeable. However, this has nothing to do with the location of the diopter ring, which BTW is exactly alike on the B&L and the Browning.

Renze
 
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Copy, and then only in the sense of taken as a model. Because Leitz was the first company to design a compact, internal focussing roof prism binocular (series) with great quality, all subsequent roof prism binoculars are more or less modelled on the Trinovids.

Renze

Hi Renze,

I agree with your appraisal. With the next generation (after a break of producing binoculars for several years) of Trinovids, Leica was very influential again. The logical consequence of internal focussing was to seal the binoculars in order to get them really waterproof. The Trinovids BA/BN were that much of a success that most other competing companies copied even their configuration scheme: 8x32, 10x32, 7x42, 8x42, 10x42 and so on.

Steve
 
Henry,

I managed to unscrew the outer ring - holding the eye lens - of the ocular assembly, and there's no doubt about it: focussing is accomplished by moving the eyepiece elements. In the way that for focussing towards infinity the eyepiece is moving forward.
Your conclusion?

Renze

Well, All I can conclude is that the B&L Elites did adopt the very unusual focusing method of the Trinovids. AFAIK they're the only other binoculars to do that.

I understand your comment about the influence of the first Trinovids, but the nifty focusing method and the Uppendahl prisms remained almost unique. It's a shame that such an elegant design completely disappeared. I would love to see re-issued Trinovids with no change to the body designs, but waterproof and with all the modern optical bells and whistles.

Henry
 
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...Do you know what changes [apart from rubbering] were made for the 2nd gen. of these bins [elites that is]? I assume phase coating but were there others? Physically, at least the 8 x, these very closely resemble the 2nd gen Elite's .

A bit OT, I always found the performance [resolution, contrast] better in the 2nd gen. Elite's, compared to the 3rd gen. My 1990 Elite's always wowed me, the 3rd gens not so much. Anyone have experience with both?

It was my understanding that the 2nd generation (i.e. first rubber armored version) Elites in 8x42 and 10x42 were optically identical to their predecessors. Interesting though that the 7x36 in that line was apparently a novel design, and not a rubber armored version of the 7x35 Classic. Those second generation Elites were not waterproofs and were certainly not phase-coated--that "half-generational" change was made later, ~1992?, (with no other announced changes to the design) with such great fanfare that it taught the consumer world about the existence of such coatings (which Zeiss and Leica had been using since ~1988 but without much promotion). The 3rd generation (and last B&L labeled) Elites (i.e. first waterproof version) were a totally new design in all respects. No 7x configuration was made. Those Elites had awesome close focus for butterflying, unlike anything else at the time, and the focus ratio was nice at close distance but way too course for comfortable use at distance (like the Nikon 8x32 LX/LXL/HG)--too easy to over and undershoot the bird. My personal experience was of an exceptional amount of variation from unit to unit in color neutrality, contrast, and sweet spot size, and I know for a fact that later production was better than early production (with some design changes obviously intended to control stray light better). Good third gen units are very contrasty with a nice sweet spot, but I too like the phase-coated version of the second generation better for the reason that it had field curvature off-center whereas the 3rd generation has a flatter field but with much more astigmatism.

--AP
 
I made scans of John Garnham's photographs of the Browning 7x35.
Enjoy.

Renze
 

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Hi Bob,

Excuse me, I overlooked your earlier post with the same question. No, I don't think there's an Uppendahl in the B&L. Inspection with a flashlight shows it to be quite different to the Leitz' so it's probably the more common Schmidt-Pechan.
I see you had your doubts about using the Trinovid's eyecups on the B&L already and yes, you're right, they're not 100% interchangeable. However, this has nothing to do with the location of the diopter ring, which BTW is exactly alike on the B&L and the Browning.

Renze

Thanks Renze,

The Leitz Prism Housing seemed designed to fit the Uppendahl. I guess that a Schmidt-Pechan will also fit comfortably in there too.

Bob
 
Well, All I can conclude is that the B&L Elites did adopt the very unusual focusing method of the Trinovids. AFAIK they're the only other binoculars to do that.

I understand your comment about the influence of the first Trinovids, but the nifty focusing method and the Uppendahl prisms remained almost unique. It's a shame that such an elegant design completely disappeared. I would love to see re-issued Trinovids with no change to the body designs, but waterproof and with all the modern optical bells and whistles.

Henry

Henry/Renze, et al,

Does this unusual method constitute an internal focusing mechanism?

Ed
 
Henry/Renze, et al,

Does this unusual method constitute an internal focusing mechanism?

Ed

Ed,

Yes. Here's a view that shows the moving internal eyepiece elements used for focusing. It would have been easy enough to completely seal the non-moving eye lens group.

Henry
 

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Thanks, Henry.

Do you have any knowledge about whether instrument magnification does or does not change with focus? That issue still nags at me.

Happy Thanksgiving to all in the USA,
Ed
 
I don't know anything definite about magnification. I'm not sure whether the front eyepiece elements moving forward toward infinity focus increases or decreases the effective focal length of the eyepiece. If moving the elements forward decreases eyepiece effective FL that would compensate (though perhaps not exactly) for the decrease in objective FL at long distance. What I really like about this method is that it accomplishes internal focus without any added optical complexity.
 
Well, your reasoning may be correct, Henry. I note that eyepiece is a standard Erfle design and the objective is a cemented doublet. Hopefully, it won't require too much theory to explain how the focusing works and the implication for lateral magnification.

Thanks,
Ed
 
Well, your reasoning may be correct, Henry. I note that eyepiece is a standard Erfle design and the objective is a cemented doublet. Hopefully, it won't require too much theory to explain how the focusing works and the implication for lateral magnification.

Thanks,
Ed

Hello Ed,

Since there are no movable positive or negative focus lenses, the magnification should be a pretty straight forward ratio of image size/distance and objective focal length/eyepiece focal length.

As an example, use a 10X, f:/4, 200 mm focal length. A 1 meter wide object at 1 km would be .0573° and the same object at 5 meters would 11.31° applied to 208.3 mm would be 41.66/.2=208.3. The length of focus of the objective would change from 200 mm at infinity to 208.3± mm at 5 meters, and the focal length of the eyepiece would be fixed at 20 mm (field stop) to maintain a collimated exit pupil.

The infinity magnification would be 200 mm/ 20 mm=10x and the 5 meter power would be about 208.3 mm / 20 mm=10.415X .

This would apply only at the optical axis since curvature, astigmatism or any other aberrations would change the effective focal lengths, hence the magnification. Because of this, it would be easier to measure the average magnification rather than calculate it, especially with internal focusing lenses that may be either positive or negative with unknown properties on the actual image size passed downstream.

So a ballpark guesstimate for this would be about a +4% change in power, if I have not gotten totally lost above.
 
Hi Ron,

We just returned from Yosemite or I would have responded sooner.

Would it make any difference in the relationship between lateral magnification and working distance if:
(a) the eyepiece moves as a unit, like the Zeiss BGAT (or most Porros), or
(b) the elements within the eyepiece move, like the Leitz Trinovid?

In case (a) the focal length of the eyepiece is fixed. In case (b) the focal length of the eyepiece is variable.

Ed
 
Hello Ed;

I am speculating here, but would imagine that it does not make much difference.

Lens law is what determines the change in focal length for varying distances from the objective and since the eyepiece “objective” is the doublet eye lens in this case, to maintain infinity projected virtual image; the image plane would have to be at effective focal point of that group.

In this case, I rather imagine that the 3 elements that move are working in the same manner as an internal focusing lens on the objective side of the image plane, which is as an internal focusing lens, only on the image side of the image plane.

Since the ratios of image size are so large for far to near focus distances, it appears to me that the ratio of the effective focal lengths is controlling the lateral magnification. ISO specifications for magnification are 5% maximum throughout the range.

Again, without the actual properties of the lenses to calculate the nodal points, this is idle speculation, but from what roofs I have measured power on, 2-4% is common. Henry has probably measured far more binos than I; he may have measured some Trinovids in the past.

Not much help, I know.
 
Hi Ron,

We know, of course, that case (a) always produces an increase in magnification at closer working distances. The question to me is whether case (b) necessarily does the same. If not, what are the optical principles involved?

I concur with you on several points, in particular that this generally has implications for internal focusing lenses on the objective side. Indeed, if one reverses the binocular so that the eyepiece becomes the objective, the focusing group would then seem to function as a focusing lens. Hence, the design principles are probably to be understood on a symmetrical basis.

My interpretation of Henry's comments in post #33, however, is that magnification might remain nearly constant "...If moving the elements forward decreases eyepiece effective FL that would compensate (though perhaps not exactly) for the decrease in objective FL at long distance." He might want to review his earlier findings, but as I recall some (if not all) focusing lens designs produced near constant lateral magnification. There was discussion about positive vs negative lenses, but I've lost track.

Ed
 
Hi ya'll,
Sorry to butt in to such a devloped exchange but it's too interesting to resist. Here's a link that describes, for some typical general eyepiece types, the varation in eyepiece focal length as the separation between the eyepiece elements is changed:
http://www.astronomyboy.com/eyepieces/ep_calc.shtml

As you can see, as the separation is increased, the focal length of the eyepiece also increases. I don't think the Trinovid's eyepiece is much different from these.

I will not attempt to go an inch further, as I would quickly sink into rash assumptions, foolishness etc.
Ron
 
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