RN binoculars (1 Viewer)

[Binastro]

I watched the channel 5 programme Warcraft showing a destroyer in operation in 2019.

On the bridge the standard binocular was the Zeiss 7x50 rubber armoured. There were rather many in use.

Also a Swarovski possibly EL of 50mm or 42mm.

There was a glimpse of possibly a Canon IS, perhaps 15x50 or 10x42L, but most unsure, as the helicopter seemed to use, possibly a Fujinon stabilized binocular.
The helicopter may be a Lynx.

I still haven't watched any episode fully, so I don't know what other binoculars are used.

There is also a ranging system, but I didn't notice any hand held rangefinder devices.

Regards,
B.

 

[Pinewood]

Hello Binastro,

I wonder how many of the Binoculars had graticules. In this day and age, acquisition of targets, navigation and ranging probably rely on radar and lasers rather than optical devices. I am curious about the absence of Hensoldt 7x50 NATO binoculars.

Stay safe,
Arthur

 

[Binastro]

I think that Gary serviced the Zeiss 7x50s, so he would know if they had graticules.

I don't know if Swarovski rooof prism binoculars were made with graticules.

On T.V. about 50% of all documentaries and movies have binoculars and/or telescopes.
An amazing array of models from the cheapest to the most expensive.

I have seen Questars, Zeiss 20x60S, Canon 18x50 IS, Leicas.
Zeiss Dialyt, numerous Bushnell.
Numerous display refractors. Some clearly modern copies of supposedly old refractors.
Numerous Newtonians facing the wrong way.

Red coated binoculars are a favourite. The cheaper the better.

Best wishes,
B.

 

[John A Roberts]

In relation to graticules/ reticles . . .

Back in ye olde days of 1964, Zeiss West Germany introduced it’s first roof prism offering the Dialyt 8x30B.
In the 1964 catalogue:
• reticles are offered as options on all of the Porro line - including the 7x50B - though not the 8x30B;
• and not on the Dialyt roof prism.
See the specification page and a mash up of the two pages about reticles.

In relation to Swarovski, besides the standard consumer market offerings, they also offer a range of products for government agencies
i.e. primarily military and law enforcement. A catalogue of 13 pages from earlier this year is downloadable as a 2.2 MB PDF at: https://ezone.idexuae.ae/storage/brochures/oFywNQu80BWsaHlkEx6QIhpxXa1jETE1ufAHTomB.pdf

Many of the products are the same as the commercial offerings. What will differ will be the service and warranty conditions associated with the purchases.
However, in addition to the regular commercial offerings:
• there’s also the IF version of the traditional Habicht Porro prism binocular in 8x30W, 10x40W and the long eye relief 7x42B, all with a RA covering; and
• some models can be had with with a reticle and/or specific frequency laser blocking filters.

A reticle is available on the IF Habicht Porro models, and also on the BTX telescope module. And the STR telescope comes standard with a choice between two projected/ illuminated reticles (see the attached graphic).

However, there is no reticle option for any of the roof prism binoculars or the ATS/STS series of telescopes that are included in the catalogue. This is most probably due to physical limitations. A reticle is typically located at the focal plane behind the prisms and before the eyepiece - so that it’s permanently in focus - as in the stylised diagram from Swarovski.

The problem with modern roof prisms designs is that due to their complex eyepieces there is a lack of available space. e.g. see an image comparing the x42 NL and EL designs. It’s from Henry at: Glass types in NL Pure-series

And circling back to the 1964 Zeiss West Germany catalogue . . .
Diagrams showing the light path of the non-B and 1st B version of the 8x30 Porro prisms can be found at: Zeiss 8X30s
And diagrams of the 2nd and 3rd versions of the 8x30B Dialyt showing the light path can be found at: Optical design of 1980s Dialyt 8x30
Again the problem would seem to be a lack of space at the focal plane in which to fit a reticle.


John


p.s. For more detail on the STR telescope including an image showing where the focal plane is located in the eyepiece, and how the reticle is instead projected via it's Porro prism system, see: STR Telescope - Reticle System

 

[Binastro]

Thanks John,

I thought that there may be problems with graticules for roof prism types.

I don't know what a tremor reticle is or how it works.

If the Zeiss 7x50s on the destroyer's bridge were mixed types, witrh and without reticles and with different laser filters it must get confusing, especially when on action stations.

I think that some officers have used their personal binoculars also, so I don't know if the single Swarovski was official issue.

In helicopters some of the Fujinon stabilised binoculars use 28 volt supply, I think, and they can have different eyepieces including image intensifiers, I think.
The cost may be £10,000 plus, which is far more than the Zeiss 7x50s.

I wonder how good the bridge windows are optically for, say Canon 15x50 IS binoculars?
I presume it is armoured glass.

The thick cockpit windows on a Boeing 747 across the Atlantic at night with a 10x25 were very good looking at a comet and stars. The stars were seen well down to the horizon, which is probably minus degrees from 37,000 ft.

There were many binoculars available on the destroyer's bridge in the documentary and many were in use at one time.

I think that one of the ranging devices was deliberately obscured for T.V. viewers.

Regards,
B.

 

[Tringa45]

A reticle is available on the IF Habicht Porro models, and also on the BTX telescope module. And the STR telescope comes standard with a choice between two projected/ illuminated reticles (see the attached graphic).

However, there is no reticle option for any of the roof prism binoculars or the ATS/STS series of telescopes that are included in the catalogue. This is most probably due to physical limitations. A reticle is typically located at the focal plane behind the prisms and before the eyepiece - so that it’s permanently in focus - as in the stylised diagram from Swarovski.

If I'm correct in assuming that the BTX module only has dioptre compensation on the right eyepiece and no provision for focussing the left eyepiece, then I don't really understand how it can be equipped with a reticle.

On traditional porro binoculars (and also Hensoldt Dialyts and the 7x40 Zeiss Jena roof) with individual eyepiece or bridge focussing a reticle could be placed in the focal plane of one of the objectives. At longer distances it would always be in focus, at shorter distances not, but that wouldn't matter as there is no requirement for a reticle at shorter distances and a close-focus capability is not needed on such binoculars.

On binoculars and scopes with internal focussing the distance between objective and eyepiece is fixed, so even for objects at infinity the positive or negative focussing lenses slightly alter the focal length of the objectives to compensate for the user's eyesight. The normally sighted would require the images of the objectives to be placed in the focal planes of the eyepieces. The near-sighted would place the objective image inside the focal plane and conversely, the far-sighted would place the image outside the focal plane of the eyepiece.

Thus a binocular or scope with internal focussing would also require a reticle with internal focussing. I believe this is the case with telescopic sights.
IIRC Steiner offered an internally focussing roof prism binocular with "dioptre" compensation on both eyepieces. Steiner supply lots of binoculars for military use so perhaps in this case they had thought of providing a military version with reticle. One could then have focussed the reticle side with one eyepiece and set the individual diopre compensation with the other eyepiece.

Thoughts anyone?

John

 

[John A Roberts]

It occurred to me this morning that there might have been one Zeiss roof prism binocular with a reticle - the IF 8x30 B GA model dating from before 2000.
And it turns out that was the case. See a flyer from 1996 along with a page from a 1998 catalogue.

Presumedly the eyepiece is simpler in construction, with a clear area at the focal plane so that a reticle could be fitted, and with any moving lenses in the eyepiece behind the reticle.
The IF’s significantly narrower FOV compared to it’s CF relative would tend to support this: 120 m vs 135 m.

- - - -
Hi John,

A couple of observations . . .

There are three patents making different claims for the X series of telescopes. Among other things, all include:
• the same optical diagrams, Figures 8, 9 and 10 (see the images from one of the US series), and;
• diagrams showing binocular viewing configurations.

On the diagrams, items 36 and 37 indicate intermediate image planes where reticles can be located
(for perspective, items 26 and 27 are the connection between the eyepiece and objective modules).


With a telescopic sight i.e. a prism-less terrestrial telescope, both of the focal planes are located in front of the moveable elements of the eyepiece
(see an image from Swarovski). So both aspects of the image, the external view and the internal reticle, are focused in unison.

If a sight has a zoom function (the ability to vary magnification), the additional moving elements are located between the two focal planes. So with:
• a first focal plane reticle, both the external image and the reticle change size in unison, and;
• a second focal plane reticle, the external image changes size but the reticle remains unchanged.


John

 

[LPT]

I can think of three military roof prism binoculars with graticules - the Canadian ELCAN 7X50, the U.S. Army M24 7x28 and the Zeiss Jena EDF 7x40, but there must be more. But all of those mentioned, however, are IF’s with conventional eyepiece adjustment focusing. I’m not aware of any Steiner roof prism military binoculars although there could be some. The only Steiner military binocular I know of was the U.S. Army M22 7x50 which was a Porro I build and not very highly regarded.

 

[John A Roberts]

To expand on John/ Tringa 45's observation for the need to be able to be able independently focus a reticle that’s not located on a focal plane . . .

On the STR telescope, the reticle is electronically projected into the prism pair, and so it is not displayed at the focal plane.
Consequently there’s a diopter adjustment dial for it on the prism housing at 11 o’clock, as seen in the image.

Similarly, with rangefinder binoculars, an aiming point along with other information is electronically projected into the right hand barrel via the prism assembly.
So in addition to the need in a conventional binocular, to provide a diopter control to address any focus disparity between a user’s eyes,
there’s also the need to be able to independently focus the electronic display.
Consequently each barrel of a RF binocular has a diopter adjustment dial e.g. see the image of the rear of an EL Range.

On RF binoculars the initial setup is:
A) Switch on the electronics, and focus the display in the right hand barrel by turning the right barrel’s diopter adjustment dial.
B) Then as with a conventional binocular:
• First use the centre focus knob to clearly focus on a distant object as viewed in the right hand barrel, and then;
• If necessary, use the diopter adjustment dial on the left hand barrel, to bring the object into sharp focus in the left hand barrel.


John

 

[Tringa45]

Thanks for the information, John. It seems the erecting prisms have been left out of figures 8, 9 and 10. Are the groups 34 and 35 dioptre correction?
In retrospect it would not be difficult for Swarovski to add dioptre compensation for the second eyepiece of the BTX to incorporate a reticle, certainly far less complicated than the changes from an STS to an STR.

Btw, I have a Zeiss catalogue from 1989 in which the IF 8x30 B/GA Dialyt is shown. Cost then was DM1295,-. A reticle was a DM120,- option for this and for the 7x50 B/GA T*, 8x56 B/GA T* and 15x60 GA T*. Of all the items available then, including the 30x60 B/GA T* catadioptric scope with optional motorized focussing, only the 3x12 monocular has survived.

John

 

[John A Roberts]

Hi again John,

In relation to your question, quoting from the patent:
'[0061] The telescope proposed by the invention may also have a lens reversing system 33. The lens reversing system 33 may have two displaceable lens groups 34 and 35, for example, which are illustrated in FIG. 8 in two different zoom positions. The displaceable lens groups 34 and 35 may be operated via an adjusting means for zooming, for example one of the adjusting means for zooming mentioned above.

[0062] Intermediate image planes lie before and after the lens reversing system. Graticule plates 36 and 37 may be provided in these intermediate image planes.

[0063] It should be mentioned at this point that the lens groups illustrated are shown purely by way of example and represent only one of several possible embodiments. It would also be possible to use flat mirrors instead of the prisms.'


. . . so as to what the actual optical construction of the three X series eyepiece modules is, that's unknown.

For those interested, patents from many jurisdictions can be found using Google Patents. Entering US2012/0162757A1 will take you to the quoted patent.


John

 

[John A Roberts]

And for completeness . . .

Swarovski did once offer an eyepiece with a focusable reticle for the AT/ST series of Porro prism telescopes (they were made from 1990 to 2002, and then replaced by the ATS/STS series using Schmidt-Pechan prisms).

The only information that I’ve found is from a 2017 eBay listing by 3prcnter. As indicated in the correspondence from SONA it seems to have been very rare, with perhaps only one production run.

And as can be seen it was a fixed power 22x offering. The serial number indicates that the particular unit dates from August (the 34th week) of 1994 (64 + 1930), and that it was the 227th unit.


John