. Russian 4 times Galilean glass (1 Viewer)

. In the charity shop today there was a meagre choice of two binoculars. A 10×25 roof prism at 4 pounds and a 4X Soviet at 6 pounds.

I chose the 4 times.
It is marked Made in the USSR on the front hinge and 4X on the rear right-hand side. On the rear left-hand side is a triangle within a circle with the capital C in the middle. I cannot remember the maker, possibly Lomo?

The strange thing is how well made and slightly complex the instrument is.
I partially dismantled it and the front objectives are triplets. Composing a cemented doublet and a single element. All surfaces are nicely multicoated, and in typical Soviet fashion the large front objectives have different colour coatings. One is mauve and the other is a yellowish mauve. There is a just discernible difference when looking through the two barrels regarding colour cast.
The front cell is complex in that there is a specially shaped rear cone section with a field stop at the back.

There is a central focus wheel at the front of the binocular on the front hinge. It is an internal focus mechanism and the instrument does not change size when focusing.
The focusing elements seem small and near to the eyepiece. All surfaces are multicoated. I think the rear may be composed of a single focusing element and an achromatic doublet behind it making three elements in all.
So there are six lens elements in total on each side.

The front aperture is 36 mm, maybe 36.5 mm.
So this is a 4×36 opera glass.

It is mainly made of metal, maybe aluminium, steel and brass with leather trimming and plastic eyecups.

There is no dioptre correction, and I need this as my eyes differ by 1.5 dioptres. However, everything is beautifully machined and there are shims et cetera. So I have just unscrewed one of the front outer cells to exactly suit my eyes. This seems to work okay.

The central resolution is good, but the edge performance is not. And even without glasses the field size is only 5° or 6°. I will measure this.

So the question to ask is. Why did they make this instrument?
The 4×22 China made binocular has a field of 16.5°. The China binocular is a much later instrument than the Soviet four times instrument, which probably dates from about 1980. Admittedly the Soviet instrument is compact.

It comes with a good quality leather case and well worn leather strap. The leather is marked inside OTK 9?-22. The instrument has seen quite a bit of use and also the leather edges are slightly coming away from the metal.

. Maybe somebody has some more information about this instrument. It certainly is not much use for birdwatching, but I will try it on the stars.

P. S.
I'm not sure if you can have a field stop in Galilean binoculars. Perhaps it should be called a ray shield or some other name?

An interesting find. Would this be the same model on the auction site?
http://www.ebay.co.uk/itm/VINTAGE-B...919?pt=LH_DefaultDomain_0&hash=item4ae9e8a55f

David

. Dear David,
. Thank you very much. The two binoculars are identical, except that the one on the auction site was made for the home market, and my one was made for the export market, probably imported through TOE.

So for six quid I suppose I wuzzent robbed.

I also bought a book for £2.

The binocular is 70 mm long.
The IPD goes from 56 mm to 72 mm. One has to appreciate that many of these types of instruments have fixed IPD.
The weight is 279.5 g (280 g).

The previous owner used it quite a bit, maybe a theatre regular.
I suppose it was made because of the compact size rather than the performance, as it is a narrow angle instrument.

I will try it later on the stars if it is still clear, although there was quite a bit of rain earlier and it was very dull.

Binastro,

It sounds an interesting instrument, and looks well made, so I reckon 6 pounds well spent ll in all. I quite enjoy looking in the charity shops for something out of the ordinary, as well as the very rare bargain of course.

The symbol you describe is that of LZOS; Lytkarino Optical Glass Factory. I have their famous Jupiter-9 85mm f2 lens in M42 mount as well as their 500mm f8 Rubinar mirror lens.

Sounds like you have the original BGF 4x36. A revised version is still available; see MFG product page:
http://lzos.ru/en/index.php?option=com_content&task=view&id=105

. Thank you pyro for the information.
I made the field of view less than the 7° stated, but it depends how near you can get to the eyepiece.

I have used the Jupiter 85 mm F/2 in M 42 mount on my Minolta film camera with a Minolta to 42 mm adapter.
it is an old-fashioned design, I think a copy of the Zeiss. It was fast, cheap and usable, but from memory has a great deal of pincushion distortion. I think that with various copies of Zeiss products the curves on the lenses were identical in the Russian versions. Also prisms on Russian binoculars can be used to repair Zeiss binoculars.

The 500 mm F8 mirror lens is of course famous, but in the Soviet version it is only geometrically F8 i.e. 62.5 mm aperture. With the Japanese mirror lenses from Nikon, Canon and Minolta the clear aperture is 77 mm, which means that the secondary obstruction is allowed for to make them a true F/8. However, none of them compensate for transmission losses to give T/8. However, the Tamron version uses enhanced silver coatings to get higher transmissions. I think this one also has a doublet corrector rather than the single corrector the others have.

I have used several of the Russian 1000 mm f 10 mirror lenses which perform well usually and are robust and were economically priced