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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Zeiss monocular 3x12 and 6x18 BT monoculars (2 Viewers)

MBS

Well-known member
Hello,

If you are the user of a Zeiss 3x12 BT or 6x18 BT monocular, I will read with interest your opinion about these two models.

These models are costly, are there other brand monoculars beeing as good or nearly as good than Zeiss ones?

Other question: do you know the difference between a "T" and a "BT" Zeiss optical equipement?

Best Regards.
 
The 'B' used to signify with Zeiss that the paticular instrument was suitable for use with glasses, that's the case with my 8x30b Dialyts but not sure if it's still the same with Zeiss's current lineup.

I'd be interested too in what people think of these - I have an old Soviet 8x30 BNU2 monocular from the mid '70s and a Zeiss Jena 'Turmon' 8x21 monocular, both of which are excellent optically, though not that suitable for use with glasses and both have a bit of a yellowy/brown colour cast. I also have an Opticron 8x20 Galleryscope, very good (though not quite top notch) optics and that amazing 30cm close focus ability! These are a couple more options for you if the Zeiss monos turn out to be a bit too pricey.
 
The 'B' used to signify with Zeiss that the paticular instrument was suitable for use with glasses, that's the case with my 8x30b Dialyts but not sure if it's still the same with Zeiss's current lineup.

I'd be interested too in what people think of these - I have an old Soviet 8x30 BNU2 monocular from the mid '70s and a Zeiss Jena 'Turmon' 8x21 monocular, both of which are excellent optically, though not that suitable for use with glasses and both have a bit of a yellowy/brown colour cast. I also have an Opticron 8x20 Galleryscope, very good (though not quite top notch) optics and that amazing 30cm close focus ability! These are a couple more options for you if the Zeiss monos turn out to be a bit too pricey.

Hello Sammyboy,

Thank you for the infos.

According to an other message (got on an other site), "T" (in BT) means that all optical surfaces are with reflection cancelling multi-layers.

I have just found the Zeiss 3x12 BT sold for 259.00 €, and the 6x18 BT sold for 199.00 €, plus 50.00 € for shipping and insurance, in Europe.

I don't know if this is the best price we can get, or not...

If readers of this message know best prices, somewhere in Europe, I thank them in advance for the info.

It seems that these Zeiss monoculars (also usable as magnifying glasses) are the best available.

Best Regards.
 
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I have the Zeiss 6x18 monocular but it does not get a lot of use.
Optically it is what you would expect of Zeiss, though the FOV is somewhat restricted.
With the objective fully extended it will focus to 25cm when the magnification is approx 9x.
The 3x12 is often used as a booster for binoculars, probably useful for checking their optical qualities, but not very practical in the field due to restricted FOV and the requirement of using a tripod.
Out of curiosity, I once used my 6x18 as a booster on my Zeiss 12x45 Conquest for 72x magnification. It worked but contrast was very poor.
If close focus and the booster facility are of no importance to you, I can recommend the Docter 8x21 monocular at a fraction of the price.

John
 
I have the Zeiss 6x18 monocular but it does not get a lot of use.
Optically it is what you would expect of Zeiss, though the FOV is somewhat restricted.
With the objective fully extended it will focus to 25cm when the magnification is approx 9x.
The 3x12 is often used as a booster for binoculars, probably useful for checking their optical qualities, but not very practical in the field due to restricted FOV and the requirement of using a tripod.
Out of curiosity, I once used my 6x18 as a booster on my Zeiss 12x45 Conquest for 72x magnification. It worked but contrast was very poor.
If close focus and the booster facility are of no importance to you, I can recommend the Docter 8x21 monocular at a fraction of the price.

John

Hi John,

The booster facility is a "no need" function for me, but I like the possibility to use this kind of small monocular as a magnifying glass, with the advantage of a greater objective-subject distance than with a classical magnifying glass.

However, the price is a little bit high, for me...

Thank you for your optionnal choice (the Docter).

Best Regards,

MBS
 
I think you're on the right track with the 6x18 vs the other sizes in Zeiss' line. I considered one but they are rather expensive here at $300.

The Nikon HG 5x15 has a .66 m close focus and a 9 degree FOV. Optically it's excellent as well. It's what I wound up with in lieu of pocket bins to carry with my evening dog walk. I like it more than I ever would have guessed.
 
Hello,

If there are Minox or Nikon alternatives, they are worth considering too...

Above all if the optical quality is close to Zeiss models, and prices enough lower (than for Zeiss monoculars).

The most interesting qualities in these binoculars, in my opinion, are: the double function (magnifying glass and telescope), plus the lightness, and also the discretion of use (I think that the monocular can be nearly completely enclosed in the hand, if the hold is done with the full hand wrapped around it).

Best Regards.
 
MBS –

Butterfly and dragonfly populations are now reaching their seasonal peak within my particular North American latitude, and I’ve found that over three years of use the Zeiss 6x18 BT excels as an aid in identifying insects. The optics are VERY high quality, much more so than I anticipated in an instrument of this type. As noted by John Russell, the close focusing is indeed exceptional. Eye-relief is above average, hovering somewhere between 14 to 16 mm. The included neck strap prevents the instrument from becoming entangled with shirt pocket flaps. This device also has the very practical real-world benefit of allowing for rapid reading of the nettlesome fine print found on prescription bottles, newsprint, and a wide variety of consumer packaging. In a pinch, an acceptable canvassing of a distant horizon can even be performed!

A slight caveat, however…

The focusing mechanism is of the “draw tube” variety seen on collapsible premium spotting scopes manufactured by Optolyth and Swarovski. Some time is required to master it, but practicing on such quotidian subjects as a Bald-faced Hornet crawling along a kitchen windowpane easily does this. Whiling away an evening staring at a newspaper containing varying font sizes and styles that has been placed on a kitchen or living room floor and repeatedly focusing upon it from varying distances will quickly sharpen your skills.

An added bonus is the structural integrity of the instrument. Enclosed in its zippered vinyl carrying case, it has survived a surprising amount of jouncing around inside my daypack. Deployed in less-than-ideal conditions over three seasons of hot, humid fieldwork, it has yet to fog or leak.

Best,
Chris Ellison
 
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Hello Chris

Thank you for your comment about Zeiss monocular.

Is there any risk that the "draw tube" focusing system become "loose" with time, due to a progressive wearing of the friction parts?

Perhaps the most important quality of this kind of monocular is that it can go with you everywhere, everytime, contrary to binoculars (even the most tiny of them).

Who among all of us never regreats to be without an optical equipement (left in the car, at home, etc.) when something happens suddenly deserving to be looked at...

Its a little bit like with photography: the better snapshots are those I missed because I didn't carried a camera when we I just needed it...

With such a light and rather small monocular it's no excuse to be without it all the day (at home, at work, while commuting, during holidays...).

Best Regards.
 
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A superb question…

I haven’t noticed any degradation in performance, but most of my viewing consists of focusing the monocular on a fixed point for great lengths of time to examine closely cooperative (read: stationary!) insects prominently perched atop vegetation. Treating the instrument’s extension and retraction mechanism as if it were a trombone could, indeed, cause mischief. The overall level of workmanship of this monocular is quite high, and I should think reasonable use and care should ensure a long life span. I often observe from inside a blind, so it has managed to avoid exposure to prolonged rain showers. Light drizzle hasn’t harmed it.

In other words, I don’t think I’ve taxed this item’s limits. For truly soaking in a vast swath of terrain in order to search for insects, a spotting scope equipped with a low-power wide-angle eyepiece (20-25X) yields the most satisfying results. A scope manufactured with an angled eyepiece orientation greatly reduces the distractions created by annoying lateral light. This technique is a bit like planting yourself in the middle of a science fiction movie of your own design. Green Darner and Halloween Pennant dragonflies the size of houses! Crickets the length of a city bus! Silver-bordered Fritillaries sporting wingspans approaching those of eagles!

Yours for the asking☺

Best of luck,

Chris Ellison
 
Hi Chris,

If you like science fiction environment, may I suggest you to try aqualung diving, or even just snorkeling.

You will discover a strange world where animals look like plants (and vice versa); and all appear to be very "aliens"; where your are nearly in zero gravity situation; where colors are odds, and sounds disconcerting, etc.

Best Regards.
 
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I can recommend the Docter 8x21 monocular at a fraction of the price.

John

Any chance you have a link to that or know where got it? I can't find it anywhere, one of the first good search hits is this thread!

The only quality monocular I've looked through so far is the Minox, I was going to buy the 8x16, they go for $150. I love that form factor, it goes in a pocket so easily because it's not round. However I'd like to take a look at the Docter if it's still for sale, they make great optics.
 
Hello,

After some hesitation, I opted for a 6 x 18 T Zeiss monocular, received few days ago.

The image is very good, clear, and the short distance focusing is an interesting option.

However, I notice that if the image is very sharp in the center of the apparent field of view, it begins to be blurred past about the 80 % of all this apparent field of view.

Perhaps is this a field curvature effect, with a defocusing consequence, in the peripheral zone?

Do other owners see the same effect?

Best Regards.
 
Hello,

After some hesitation, I opted for a 6 x 18 T Zeiss monocular, received few days ago.

The image is very good, clear, and the short distance focusing is an interesting option.

However, I notice also that if the image is very sharp in the center of the apparent field of view, it begins to be blurred beyond about 80 % of all this apparent field of view.

Perhaps is this a field curvature effect, with a defocusing consequence, in the peripheral zone?

Do other owners see the same effect?

Best Regards.
 
Perhaps is this a field curvature effect, with a defocusing consequence, in the peripheral zone? Do other owners see the same effect?

Yes indeed, mine has field curvature but negligible astigmatism. At close focus the field curvature seems to diminish.

John
 
Yes indeed, mine has field curvature but negligible astigmatism. At close focus the field curvature seems to diminish.

John

Hello John,

Thank you for the info.

I have a confirmation, now, that the field curvature is the culprit for the problem of defocusing beyond 80% of all the field of view.

I can get an excellent sharpness, at the periphery of the apparent field of view, if I focus the monocular for this result, but now this is the central zone that is blurred; and when the picture is sharp in the central zone, the peripheral one is out of focus and blurred...

For a Zeiss product, the fact that about 20% of the field of view is not usable is a little bit excessive, in my opinion.

Best Regards
 
Sharpness over 80% of the field from the center of the view is pretty good for any binocular or monocular. You only have to move it minutely to center anything in the outer 20% that you want to look at.
Bob
 
Hello,

After an other and this time thorough test, I must notice that the degradation begins beyond 60% (and not 80%) of the apparent field of view.

For this test I used garden steel railings with nine bars being visible in the field of view, one being the central one, and four other ones on each side.

The tip of the central bar is very sharp, as are the tips of two other bars on each side, but the tip of the third bar on each side begins to be slightly blurred, and the two other tips of bars (number four and five) are more and more blurred.

Five tips of bars being visible in the radius of the field of view, the usuable sharp image include three of them (central one and two lateral ones).

As five bars equals 100% of the field of view (on the radius), three bars equals 60% of this field of view (where image seen is good).

So I think that I can objectively consider that only about 60% of the field of view is really of a good optical quality, in this Zeiss monocular.

Not up to par with the reputation of this manufacturer, and the price of the item, again in my mind.

But perhaps other monoculars, of other manufacturers, are worse...

Best Regards.
 
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