Antique Goerz D.F. 99

[Izar]

Here is a review of a pair of C.P.Goerz D.F.99 German Army prismatic binoculars.

C.P.Goerz (Carl Paul Goerz 1854 - 1923) started life selling Mathematical instruments to schools.

By around 1887 his interest turned to selling cameras, this was followed a year later by the take-over

of the workshops of F.A. Hintze's, creating the company Optische Anstalt C.P. Goerz.

With this company, Goerz produced cameras and lenses. By 1890, Goerz had moved production

to Berlin-Friedenau.

Goerz was not content with just selling one product, and quickly the company was producing

a whole range of various optical instruments. Seeing the potential for Ministry orders, he started to develope

a range of binoculars in the late 1890's, and in doing so, he was competing against his major rival of Zeiss.

In the year 1899, Goerz produced a prismatic binocular, which he offered to the German Ministry for testing.

This proved successful, for early in the year 1900 an order was placed by the German Ministry and full scale

production was started of the model known as "1899".

Zeiss was already using a well established D.F. code system for their Ministry binoculars, so Goerz kept the

system and stamped the binocular "D.F.99"

The D.F., stood for "Doppelfernrohr" (Double-Telescope), and this can be traced back to binoculars that Zeiss were

producing in the year 1874.

In the year 1903, more orders were placed, and Goerz opened a department at the Berlin factory solely for the

production of military optics. The new model was known as the D.F. 03. The Goerz business rapidly grew, and

they quickly became the worlds biggest producer of military optics. It was also around this time that they started to

produce a series of refracting telescopes.

The year 1903, also saw the company floated on the Stock Market. Never one to miss out on advertising, Goerz

proudly proclaimed that his company had produced around 130,000 binoculars by the year 1907.

This got under the skin of his rivals Zeiss, who made a counter-claim a year later. It was clear that Goerz was

rapidly becoming a thorn in the side of Zeiss. The company also went on to open branches in several countries

around the world, including the UK..

Interestingly, Goerz supplied the British War Ministry with optical instruments, and had previously worked with the British

company Barr & Stroud, becoming their sole representative in Germany in the year 1898. As part of this agreement,

the British company was allowed to send a representative to the Friedenau works, and James French thus worked at

the Berlin factory for a year, studying all aspects of optical production.

Goerz was now a highly successful company, and with the out-break of World War 1, yet more business was placed

by the both the German and Austrian War Departments. The company was producing binoculars with a 30mm objective version

appearing to have been the standard instrument for officers during the War, lower ranks had to make do with Galilean

binoculars. Rifle scopes, U-Boat periscopes and searchlights were also produced for the Government.

With the end of WW 1, things quickly started to go bad for Goerz, for the company appears to have struggled

in the post war chaos of Germany. The situation was compounded even further by the Peace Treaty of Versailles

which prevented Germany producing military equipment.

In 1926, the German branch of Goerz was merged with Contessa-Nettel, ICA and Ernemann to form a new company

known as Zeiss-Ikon by the year 1927. Zeiss was the controlling share-holder of the new company and declared

that lens production would only be carried out by Zeiss, thus the coffin-lid was finely screwed down on their old adversary

of Goerz.

During its time, Goerz had produced thousands of optical instruments for both military and civilian use.

REVIEW OF GOERZ D.F.99 PRISMATIC BINOCULAR

Unfortunately I can't find one single image of the binocular that I have The nearest I can find is in this link:

Instruments for Science, 1800-1914: Scientific Trade Catalogs in Smithsonian Collections

and: Binoculars (NAV0066) - National Maritime Museum

The body shape is the same as mine, but the D.F.99 does not have any focusing wheels between the two binocular

bodies and the two bridges are different.

The binocular has a distinctive angular shape, with the body appearing to have been made from cast aluminium.

Inside are various ledges for the prisms to sit on. The condition inside the body is very clean indeed, and it was sobering

to think that the last time someone inspected the prisms was probably when the instrument was made some 110 years ago.

The covering is brown leather and was not stitched, but instead Goerz chose to glue the leather to the body. At each end of the bodies are

heavy brass bridges, running along the inside of each body are heavy brass plates that connect the body to the bridges.

At the eyepiece end is a small set-screw on the bridge, when the correct eyepiece distance is obtained, this screw is tightened

up. The binocular also has what looks like the original leather neck-strap.

On the left-hand prism housing plate is stamped "C.P.Goerz Berlin", underneath this is "D.R.P".

On the opposite plate is "D.F. 99", and underneath this is "P. No". When Goerz made this model, it was offered

to officers of the Prussian Army at a special discounted price of 95 German Marks. In return the paying officer could assign a unique

serial number to the binocular, thus the P. No. stood for "Private Number". The number on my model is a very low 3 digit number.

Wether this number is a serial production run number is not known, if it is, then the binocular I have must have been one the first

to be made.

It also raises the possibility that the number is a personal Army number relating directly to a Prussian officer?

If so it might just be possible to trace the original officer who purchased the binocular if this is the case.

It is known that these binoculars were used by Artillery officers. I have also found a picture in an old book of a German

Officer with a pair of these binoculars.

Goerz also supplied yellow filters, distance measuring reticle and compass at extra cost.

The lenses are tiny, at only 20mm diameter, and the magnification is x7. Each eyepiece is focused individually by turning a knurled

metal ring around the base of the eyepiece stem. Instead of rotating, the eyepiece moves up or down. There is a marked scale

running all the way around the eyepiece stem.

All metal parts are painted black and are made from brass and aluminium or alloy.

When using, the angled sides of the body slip very nicely into the hand making them nicer to hold than my pair of modern Zeiss 8x30.

In spite of the tiny lenses and un-coated prisms, the view is quite bright in daylight and the optics are very sharp indeed.

The eyepieces have good eye-relief, and observing with them is very relaxed.

Goerz described his binoculars as being good in low light situations in the early morning or late evening.

He was also one of the very first to promote his binoculars as being good for astronomy and in particular

the study of variable stars. It has been estimated that the un-coated surfaces in the Goerz have a light-loss

of around 37% . In my skies I was struggling to pick out stars fainter than magnitude 7.0. But I did manage to see M13 as a

very small fuzzy ball. I estimated the field of view at around 6°.

Goerz D.F.99

PROS

Very nice to handle , sloping body sides fit the shape of the hand extremely well.

Nice comfortable viewing images.

Extremely sharp optics, as good as any modern day binocular.

One of the very first mass produced prismatic binocular.

A nice history piece.

CONS

Small objectives and un-coated prisms, providing limited use for astronomy.

As they only cost me £11, I'm not complaining, for I now own a piece of interesting history for my collection.

If any one can add more information for Goerz then please post, for I may be lending the binoculars for display at a local

Museum. so any information would be helpful.

Thanks for reading.

[argonaut]

What a excellent read that was.

Thank you for taking the time to give us all the history in the binoculars you own.

I look forward to more history. I find it fascinating how optical companies come into being in the first place. I suppose information is available on the web. It's just that I find reading your reports so easy and enjoyable.

Glen.

[Izar]

Many thanks Glen

I should also add that Goerz learnt his craft of optics

making while serving as an apprentice at the camera and lens

making firm of Emil Busch A.G., Rathenow, Germany.

His first company was founded in the year 1886.

[Izar]

At last, found an image of the D.F.99 on Ebay:

GOERZ D.F. 99 Fernglas 7 x 20 - (eBay.ca item 350190846435 end time 22-Apr-09 12:41:26 EDT)

What I notice on the ebay one, which going by the serial number

appears to be a later production run, is that Goerz had altered

the shape of the lug for the leather strap, and the paint colour.

[Izar]

As an up-date to the review of the D.F.99, I completely stripped them down and cleaned all the

prisms and lenses. The standard of engineering and machining within the prism body is truly remarkable.

Over the last week, I've been using them extensively and have found them to be an excellent binocular.

Also after using them in better sky conditions, I've revised my opinion of the limiting magnitude reached by

the small 20mm lenses. According to Goerz advertising from April 1899, the limiting magnitude for their Trieder

binoculars was mag.7.5 and 8.0 for the x3 and x6 models, while the x9 and x12 models would reach magnitude

8.5 and 9.0 on a clear moonless night. The x3 and x6, had 15mm lenses, while the x9 and x12 both employed objectives

of 20mm.

As the D.F.99 is x7, I would think that they would be somewhere in between the x6 and x9 models. It has been predicted

that with the 37% light-loss, the x9 models would reach magnitude 7.8, rather than mag.8.5 as stated in the Goerz advertising.

During the week, I had a good night (for me) with a naked eye limit of around mag.5.0 - 5.0. While observing R UMa,

I managed to see a comparison star of mag.8.2 and then glimpsed a fainter star, which turned out to be R UMa. I estimated

the magnitude of R at around mag.8.3/8.4. Several other variable stars were checked out, and in all cases I could not

detect stars of magnitude 8.5, but 8.3/8.4 was observable.

It seems to me. that even with the light-loss, the information given in the Goerz literature is correct in the figures that it quotes.

Goerz also mentioned how much better their prism binoculars were for astronomy, when compared against Galilean binoculars.

Going head to head against my Dollond's, I have to say that I think the Dollond Galilean's is a better instrument for astronomy,

and I cannot see any real benefits that the prism binocular had over the Galilean optics that could be purchased at the time.

[onecollector]

Great article, on my D.F.99, the P. number is 286, also the serial number on the underside of the RHS brass bridge is 58051. Also on the D.F.99 plate there is an etching of a bombardiers device.I can upload if anyone is interested.