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12x50 Trinovid BN and observations

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#1 ronharper



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Posted 07 February 2010 - 10:29 PM

Hi All,
I picked up this used Leica BN 12x50 not long ago. It is very nicely built, and I have been enjoying the comfortable view and especially the center focus. I have complained here that I have to tweak IF eyepieces most nights to get the best view, and that I have a hard time getting it just right sometimes. Bless your hearts, who have no such difficulties. But for me, it is so nice just to squeeze the Leica into sharp focus while watching normally with both eyes. The stars focus to excellent sharpness in this bino. Its silver coated Schmid-Pechan prism optics, and generally more reflective-looking coatings, lag the Fujinon FMT in transmission (BNs have been measured at about 86% transmission vs the big Porros' fabulous 95%), and as you'd expect the stars look a little bit less fierce and colorful. The sweet spot in the Leica is satisfyingly large to me, and stars at the edge are not annoyingly bloated as long as the attention is near the middle as usual, in my easy-scan braced hand held manner. But make no mistake, there is no contest with the 10x50 FMT there. Stars merely half way to the edge in the Leica are already as distorted as stars on the very edge in the Fujinon! Such sensational edge correction is something I am awed by, but never felt it to be a meaningful advantage. Mounted on a tripod, however, where it might be a bit more trouble to reorient the binocular, I suppose it would increase the usefulness of the Fujinon significantly. What the Leica does have over the 10x50 Fuj is of course magnification, which I have found outweighs its lower transmission and permits smaller dimmer objects, and more fine details to be seen. The apparent field of the Leica (68deg, 5.7 deg true according to specs) also looks larger, another thing that is sort of nice but no biggie to me.

I finally got a good clear night, albeit with the nearby outdoor skating rink, the bane of my winter existence, blazing. I have an astronomer friend who skates, and says he always thinks of me when at the bottom of that hateful "pillar of fire". Isn't that sweet?

So here are a few examples of what she'll do. These are picked out because they push it in one way or another, but you can bet I just enjoyed plenty of easy views too!

First, some dim objects and cluster cracking:
oc ngc1245, Per. A fairly difficult small averted smudge. Never seen in 10x50, usually seen in 16x70.

oc ngc663, Cas. 6 stars seen. Also companion clusters 654, easy and associated with a conspicuous star, and 659, somewhat dimmer.

oc ngc7789, Cas. A big favorite with lots of you, too, I imagine. I am always just floored that the 16x70 gives moments of resolution on this object, and am happy to find out that the 12x50 will do it too, but of course it pushes the averted vision technique harder, and isn't as impressive. But, still, wow, it's---a cluster! I love that feeling!

oc Tr 1, Cas. A small and slightly elongated smudge.

oc M35, Aur. A nice degree of resolution seen, but I could not resolve the stars along the curving "smile" or whatever you call it, as I have been able to do sometimes, with some difficulty, with the 16x70. Companion ngc 2158 was easily seen, and on another degree to the west, the dimmer oc IC2157, which I have never been able to see with 10x50.

Next a few doubles:
There's a nice double in oc ngc1502, at the end of Kemble's Cascade. This one was split wide.

59 And, marginally splittable at 8x, but easy at 12x, and I could make out the different brightnesses of the two components.

29 or Pi And, the companion to the S was easily separated but quite dim. I have never seen this at 10x.

2 Pup, which I can split with difficulty at 10x, easy now at 12x and again, with the luxury of seeing the difference between the two stars.

"Winter Alberio", Herschel 3945, found off Puppis by extending a line from Adhara through Wezen by 3 deg. The blue star showed only a trace of color. Not the brilliant color fest seen through the 16x70.

And the bugaboo deluxe,
Trapezium. One tiny star was sharply split off to the NE, and there was a trace of haze riding hard against the bright star, to the W. This was tough, and I could not have done it had I not practiced many times with the 16x70 and known exactly what to look for.

Finally, an example of what I call the "ample" critically-enough sharp "sweet spot".
The Pleiades, about 2deg across. The impression was that all the stars were sharp (more than I can say for the 8x42 Zeiss FL), for a very satisfying view at 12x.

So, that's it. I reckon sure as heck a Nikon 12x50 SE would beat it. I just have an irrational weakness for these Leicas somehow.

PS. Edited to make a correction and add observation of Pi And.

#2 chris charen

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Posted 07 February 2010 - 11:52 PM

Good report. I have had a green Leica 12x50 BN Trinovid for approx. 4 months. Just to add that Leica also provide an impressive after sales service. They refurbised in Germany my 12x50's and removed several small micro scratches on the oculars. This was free of charges with no questions asked.
The Leica Trinovids BN's series came out in January 2001.
The BN series Trinovids replaced the BA Trinovids which came out in 1990. The BN's had closer focus then the BA's as well as having ongoing improvemnents to the lens coatings.
The BN's were relatively short lived with that series being phased out in 2007. The lighter Leica Ulravids which came out in 2003 slowly replaced the BN's. The Ulravids were then replace by the current Ulravid HD series with the Fluoride [FL] glass in 2007.
Just to reinforce the excellent optical and build qualities of these Leicas as ronharper states.
Central resolution and the contrast of the image is excellent. There are a few binos that give you that 'wow' factor when you view through them and the 12x50 Leica series with the 68 degree Afov is one of them.


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#3 RichD



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Posted 08 February 2010 - 07:32 AM

Thanks for that interesting read Ron.

What is the overall contrast like on the Leicas? I'm assuming excellent as you partially resolved 7789! (quite a feat really for a handheld 50mm bino)

Any further plans to add to your alpha-roof collection?


#4 Wes James

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Posted 08 February 2010 - 08:33 AM

Nice report, Ron-
Nothing like the feel of quality in your hands!

#5 ronharper



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Posted 08 February 2010 - 02:42 PM

Nice pic, Chris, ooh I can't wait to get home now!

Rich, if you mean the contrast between how bright the stars are and how dark the sky is, then the BN is down a notch from the 10x50 Fujinon, as you'd expect from its lower transmission. I believe that is the dominant cause, as there is little light scattering at night to murk up the view, and the Leica is better than the Fujinon 10x50 (one of its few weaknesses) at controlling scattered light anyhow. That Fujinon is the best I have ever seen in that regard. I feel sure the newer Leicas, with better coatings, would come closer. The BN shows more because of its greater magnification, and equally sharp focus, but optically I don't think a top quality Porro is going to be beaten.

For me, its biggest advantage is ease of use. That's not sos I can just luxuriate in laziness either--it is a real advantage that lets me spend less time and energy fooling around, and more time observing. That's very different from, but perhaps more important than, a few percent transmission.

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