TheSkySearchers

I bought a pair of binoculars again. Although I had considerably thinned out my collection, every now and then a candy passes by on the secondhand market, whose temptations I can hardly resist. In this case a rare classical Hartmann Bernina 8X30. This little sweetheart must be 40 to 50 years old, but arrived in reasonable condition and perfect collimation to me. Complete with a cute bag (according to my wife). Hartmann was a small German binocular manufacturer which produced until 1992. Zeiss has the name, Hartmann the quality. A real vintage and classical beauty! The designation "Weitwinkel", German for wideangle, means that it was produced for the German market. The seller was honest about the shortcomings: the picture was somewhat foggy.

Well that's allowed at that age. Over the years, the internal grease starts to evaporate and that greasiness deposits on optical surfaces. A nice soapy water for the prisms and lenses was not a luxury. Because I did not want to spoil the excellent collimation, I actually only cleaned all accessible optical surfaces and therefore left the prisms in place. This way only the least exposed surfaces of the prisms stayed untouched.

The robustness and ingenuity of how parts were made somewhat surprised me. For example, the prisms are collimated with a kind of wedges that can be operated from the outside, if you at least have removed the bolts from the frontplates (covers). A normal instrument maker screwdriver can then enter the unit, with which you can adjust the prism. I was familiar with this wedge system, but I had never really had it in my hands. Isn't it called Goerz or Gurz-wedges?
The lenses had already been cleaned before, but some residue was left behind on the inside. Of course I removed that. Focusing is quite smooth, except near the "infinity point". Further investigation showed that the focusing axis is not completely straight. It seems to me that the binocular has tumbled once, although no outside damage can be seen. This is not a nuisance, but you can feel it as a little more resistance near the focussing-point.

The image is surprisingly clear, much clearer than I expected from a seventies / eighties binoculars. The coating is very similar to that of a Zeiss Jenoptem 8X30, but the image is less amber-colored than the Jenoptem. The Bernina gives a clearly less yellowish image than a Jenoptem. Image sharpness on the optical axis is, as you would expect from a classical top instrument from those years, simply excellent. Of course, some blurring appears on the edge, after all, it is a wide-angle instrument with 8.5 degrees of field of view. The Jenoptem has a fractionally larger field of view. Behind the lenses are neat conical diaphragms that prevent extraneous light from penetrating too deeply, but again: it is a wide angle in which that problem is almost impossible to eliminate. The image I had last night on some bright stars, a few deepsky objects and the Moon were a great pleasure, although I'm not going to use it for astronomical purposes.

All in all, I am very satisfied with this Hartmann, which I will take on a sightseeing tour rather than my 8X30 Jenoptem. The less yellow colored image is certainly favorable . As a tourist Feldstecher (German for bino's) a nice competitor for my 7X42 Habicht which, although optically superior, has a smaller field of view. But let me be very honest: I also think it is beautiful to look at. A nice place on the shelve right beside her Zeiss brother will do as well.

Blood is thicker than water .... despite my cleaning rage, the right half still showed some dirt. I decided to chance it and removed the prism on the eyepiece side on the right. This way I could clean in principle all prism-surfaces in the right half. Then I mounted it again and collimated. That went all right. Not really a much easier collimation than I'm used to, but it worked.

Very unfortunate this brand does not longer exist. When I got the binoculars in and looked through it for the first time, I immediately sighed, despite the foggy inside : "Sow!" An amazingly calm, sharp image and as good as neutral in color was shown to me. The contrast and light- transmission was far more better after cleaning. Actually not a match for the contemporary Carl Zeiss Jenoptem I compared it to. My Jenoptem has the legendary T*- coating. Details were the same, very sharp image but contrast of the Bernina was higher and the color of the image was far more neutral.

In the various comparison tests regarding light transmission that Gijs van Ginkel did / showed, it becomes clear that Hartmann's instruments surpassed their expensive contemporaries. Hartmann's optical workshop consisted of only 20 people...
https://www.houseofoutdoor.com/wp-conte ... 17-HoO.pdf

Hartmann did everything to achieve his goal, to make instruments with the highest light-transmission and contrast of his time. Kogaku Nikon already existed but came 10 years later with their Nikon porro 8X30 E-series. Other brands switched to roof prisms. In the porro 8X30 class that I am writing about now, the Bernina's and the Hartmann compacts can be called the champions of the 70-ties and perhaps also the 80-ties.

But even now the Bernina will effortlessly be able to come along with, or will come out as a winner above the many tourist binoculars which populate holiday suitcases and dashboards.

Hello John,

thank you for the very nice and helpful review!

Yes, the Wetzlar area with Leitz, Leica, Hartmann, Hensoldt, ..., Seibert, division of Zeiss, and formerly also Docter,
used to be the birthplace of finest optical technologies and instruments.
And your Bernina is certainly a milestone in this legacy.

Glad, you have cleaned away the fog, and wishing you to enjoy the new binos,
JG

Congratulations on the acquisition and restoration!

I have cleaned the left side as well, by taking out the prisms and giving them a nice soapy bath too. All prisms, lenses and fieldlenses have been cleaned by now. Before, a passer- by wouldn't have noticed the difference between the two halves, but I thought I could tell the difference. I think it was more between the ears, than in the eyes.

Since I had all the time in the world ( Sheltering for mr. Covid at home with an unreliable internet connection) it was just a matter of time when I would do it and this was the appropriate opportunity. I sat down for the collimation, drunk a cup of coffee and had a good thought about the movements of the prisms. To my relief it took only five minutes or so to bring back collimation to the original level.

At last I could see through the clean bino's like my ancestors had done. I can tell you, they had nothing to complain about, not even to modern standards.

Thanks for this John. They sound great: a good acquisition! Not a brand that I ever seen in Australia.

I picked up a pair of Barr and Stroud 8x30 Wide Angle recently. Like yours they look very nice from the outside, but unfortunately unlike yours they have some internal fungal marks, and so far I have found it impossible to fully dismantle them for a complete cleaning. They also don't have any discernible way to collimate the prisms; in fact they have a couple of tiny strips of foil placed strategically in the prism housings, presumably from factory collimation- something I have never seen before. Dare I say that this might reflect a difference between British and German engineering? (Yes, I have owned and or worked on several British Leyland cars!)

I have cleaned what I can and their images are not too bad, but not a patch on my Habicht 8x30's (see my next post...). They cost me nothing though, so you get what you pay for!

All the best, and keep safe.

Dean

DeanD wrote: ↑Fri Mar 20, 2020 1:30 am(...)They also don't have any discernible way to collimate the prisms; in fact they have a couple of tiny strips of foil placed strategically in the prism housings, presumably from factory collimation- something I have never seen before. (...)
All the best, and keep safe.
Dean

Hello Dean,
I have seen this type of collimation only once before. I had to open up the bino's for they had been lying in the rain ( quite stupid) for a while and the moist inside dried up terribly. Unlucky for me it was the very first time I dismantled a pair of binoculars. So I ruined the final collimation all together. Luckily I found a copy of exact the same pair of binoculars several decades later on a secondhand market.

You'll probably know the following already, but it might come in handy for others who read this.

If I knew then what I know now I'd open it up and photograph the position of the strips.
Dismantle only one prism,let us say on the left eyepiece-side so one can clean all optical surfaces of that prism and the flat front side of the prism that is still in the house. Then clean the sloping sides of the prism that still is in the house, without taking the prism out.( In order to do so the objective and coverplate have to be removed too) That way all surfaces are cleaned, but collimation has to take place with only one prism. Based on the principle if you deal with variables, deal with one at the time. That is where I went wrong 45 years earlier. Collimate the left side and then start with the right side of the bino's.

If possible try to leave the strips in place. When they come loose make a note and mark where they come from. And if possible measure their thickness in case you have to replace them.( they are easily damaged) Replacing: household alufoil is typical 0,01mm thick, measured with an analog micrometer. If you know the thickness of the strip it means less trial and error if they are damaged or cracked.

Let's be careful out there!