I bought this 12x50B Nobilem a couple of years back, but it saw quite limited use until this year, when the closure of two of my favourite spots meant that I started putting more effort closer to home. Two of the locations I started putting in more time require scanning for birds at long distances (often over one mile). For this job the 12x50B is in its element. Used from a seated position I can get it steady enough by bracing my elbows on my knees, and I find that the distant targets I'm searching for register more easily to my eyes with 12x magnification than 8x or even 10x, thanks to their simply being larger.
In use this binocular is somewhat quirky compared to a modern roof design, the focus wheel in particular being not exactly easy to reach thanks to the huge prisms (Holger Merlitz mentions the exact same thing in his write-up about the same binocular). Apart from that it is not too different to the Zeiss West 10x50 in use and seems similarly stable, possibly because the rubber eyecups help keep it steady to my face. Although nominally a 'B' model, eye relief is insufficient for me to use it with glasses, but in use this is rarely an issue. The rubber eyecups are most comfortable and block off side light extremely well, making for a most immersive view - I wish the 10x50 had them. This model is more compact than the later longer-bodied Nobilem and has a slightly wider field of view; I suspect the older T3M coatings are not quite as good as the later model, but are good enough, better than the single-layer coatings on the 10x50 Oberkochen. There is a slight greenish cast to the image which I'm not enamoured by, but which I can live with. Sharpness is good and this binocular seems to eliminate the astigmatism in my right eye that manifests itself slightly in the 10x50, though this may be primarily due to the 12x magnification. Edge performance is reasonable.
I had a bit of buyer's regret after purchasing this binocular, but it's now found a valuable niche. I've actually come to prefer it (for that specific spot anyway) to my brother's 10x56 SLC, which although noticeably superior optically, is heavier and less handy.
PS. Since my last post I've continued to use the 10x50 a lot. I have to say the more I use it the more I find myself liking and admiring this old masterpiece. Bright summer sun blasts through the 1960s era coatings (there are times I'm actually grateful for the edge being taken off dazzling white clouds) and there are some light conditions and times of the day when it just seems to work beautifully well. I would still, of course, prefer if it was multi-coated, and also if it had similar rubber eyecups to the 12x50B (or indeed the 10x40 Dialyt). I did order a pair of aftermarket rubber eyecups, but they didn't fit well to the existing eyecups. If I were more handy with a lathe I'd machine a new set of eyecups.
The 10x50 has a bit of the yellow cast Islandboy mentions in his 7x50B (but less so than the 8x30 I also have) and although on a bright day it acts a bit like sunglasses, in greyish light the yellow cast becomes more noticeable. On balance I would rather the image be as colour neutral as it is on eg. my Leitz Binuxit or Swift Holiday of roughly similar vintage.
