Duovid Optical Construction (1 Viewer)

Unique among the premium brands, Leica offers a binocular with a limited ‘zoom’ capability - the Duovid
More correctly it’s a dual magnification system, with the higher magnification providing a 50% increase in power

The Duovid was introduced in 2002 and comes in 2 models: 8+12x42 and 10+15x50
See both the attached specifications (indicating that each model has 11 lenses per side), and a drawn cutaway view of the x42 version which gives some idea of the internal construction

I recently came across 2 images taken from different angles, of an actual cutaway Duovid x42, that make the optical construction much clearer - and prompted this thread
The first image is from: https://michaels.com.au/blogs/camera-review/leica-noctivid-binoculars-simply-amazing
And the second from: https://imgur.com/gallery/3XA9G3M

As can be seen, the construction comprises:
- 4 objective lenses in 3 groups (2, 1 + 1 focusing lens), and
- 7 ocular lenses in 4 groups (2, 1, 2, 2)
The first 3 groups in the eyepiece move in unison when the power is changed, with the rear stationary group sealing the end of the unit

** EDIT: after having had another look at the two images of the cutaway unit, and then comparing them to the drawn cutaway,
it seems that the first eyepiece group is stationary, and that only the middle 2 groups move
i.e. the middle 2 groups seem to be in a cylinder, that can slide inside a larger housing, that has the front and rear groups at the two ends **


The convenience of the Duovid's dual power - combined with high optical quality - comes with several limitations compared to comparable conventional binoculars:
- extra weight, smaller field of view and limited eye relief (measured on the x50 as 12 to 13 mm from the eye lens surface - see Roger Vine below)
- and of course cost
And as the Duovid is essentially a low production speciality item, many of the updates that have been made over the years to other Leica binoculars, have not been applied to the Duovid


While there’s not a lot of information available about the Duovids:
A) Roger Vine has provided a detailed review of the 10+15x50 (and comments on the 8-12x42) here: http://www.scopeviews.co.uk/LeicaDuovid.htm , and

B) Gijs van Ginkle has published transmission data about a 2010 production x42 unit
It’s from slide 32 of Gijs’ 2017 presentation on Multifunction Binoculars and Telescopes (comprising 111 slides and 19 MB) at: https://www.houseofoutdoor.com/verrekijkers/verrekijkers-testen-en-vergelijken/


John

Just to repeat previous posts

I enjoy my Duovid 10+15x50s for distant birding of shorebirds and raptors and astro for eclipses with filters.
Very specialized and not all around, but good at what they do.

edj

Very interesting information John - thanks for the thread :t:

If the weight, limited Fov, and ER issues could be solved, I'd love a state of the art 7.5-15x (45 or 50). FL, HT glass, the works. The Uber bin could also include an IS button (ergonomically located !) that could be optionally engaged for hand holding at 15x.

If such a bin could be brought in under 750g (and with CFRP, etc there's no reason for it not to), with ER suitable for glasses wearers, and with at least 66° AFOV, I 'd be on it quicker than a seagull on a hot chip !





Chosun :gh:

Great info John!

I've always thought the Duovid is a beautiful binocular. I bet it's time intensive to make. I'd probably own the 8-12X42 if the eye relief were even 15.5mm.

My main binocs are duovid 8+12's.
I wouldn't necessarily recommend them to a birder, and the minimum focus is totally unsuitable for insects, but they work well for my uses, and my reason for buying them..

I do surveys for Marinelife on the channel ferries. The bridge of a ferry is a long way from the sea! and telescope/tripod aren't permitted.
The duovid at 12x gives that little bit extra power. In fact a team of 1 observer with 8x and me looking further out with 12x often yields good results. I definitely see and identify more storm petrels, than I did previously. Distant Divers in flight got easier etc.

Elsewhere, I have them at 8x, and switch to 12x in open habitat, or if I want to take a slightly closer look at something. 12x often squeezes an extra i.d. feature that wasn't visible at 8x.

I was slightly concerned when I bought them, and thought the measure of success or failure for me would be if I lost birds due to the binocs, either the narrower field of view, or when switching between the zooms. I don't believe it has, but it is another choice, which maybe complicates things further.

i.e. There's a bird, I need a closer look, do I zoom the Duovids up, take the scope of my back, or take a photo!!

I have a pair of Duovid 8+12X42 in green. They are great and I love them. The curvy profile is particularly appealing to me. The field of view is no problem, the eyecups are among the best that have been ever designed: their rear end bend innards and help keep the eyepiece closer to the eye.

To inspire some Leica Love for the Duovids, a pair of images:
- the first from Leica
- the second showing the alternative green version

The second is from the Dutch site ‘Twentse Vogelwerkgroep’, which has a series of binocular reviews by Jan Meijerink
I’ve attached a list of the reviews that can be found here: https://tvwg.nl/ovz-kijkers.shtml
and Google Translate produces comprehensible English versions

Jan’s review of the Duovids compares:
- the 8+12x42’s performance to an 8x42 Leica Ultravid (pre-HD), and
- the 10+15x50’s performance to a Canon 15x50 IS
see the attached table


John

It makes sense that Leica would have been the one to do this. Back in the '90s they came out with a trifocal (not zoom) lens for the M rangefinder camera, 28/35/50mm. A unique, very elegant idea, given that the discrete finder frames didn't allow for continuous variation. (It was f/4.) This seems not to work quite so well in a bino though, just too many compromises for most of us. A reminder of the relative complexity of binos, I suppose.

I sold mine!
I tot the 10-15 in use for 5 years and I think it is outdated nowadays
It is heavy , has low FOV and horrible for glass wearers

Yesterday I came across another image of a cut away Duovid

Usefully, it confirms my assumption as to the operation of the ‘zoom’ function in the eyepiece optics:
- the front and rear groups are stationary, and
- the two middle groups move in unison to alter the magnification
(compare the location of the 2 middle groups to the previously posted cut aways)

The image can be found at Leica Camera Forum Wiki: https://www.l-camera-forum.com/leica-wiki.en/index.php/Duovid_8_+_12_x_42


John

tenex said:

It makes sense that Leica would have been the one to do this. Back in the '90s they came out with a trifocal (not zoom) lens for the M rangefinder camera, 28/35/50mm. A unique, very elegant idea, given that the discrete finder frames didn't allow for continuous variation. (It was f/4.) This seems not to work quite so well in a bino though, just too many compromises for most of us. A reminder of the relative complexity of binos, I suppose.

Click to expand...

And later a super-wide angle Tri-Elmar (WATE for short) 16/18/21mm...

Chosun Juan said:

Very interesting information John - thanks for the thread :t:

If the weight, limited Fov, and ER issues could be solved, I'd love a state of the art 7.5-15x (45 or 50). FL, HT glass, the works. The Uber bin could also include an IS button (ergonomically located !) that could be optionally engaged for hand holding at 15x.

If such a bin could be brought in under 750g (and with CFRP, etc there's no reason for it not to), with ER suitable for glasses wearers, and with at least 66° AFOV, I 'd be on it quicker than a seagull on a hot chip !





Chosun :gh:

Click to expand...

Hello,

Yes this would be interesting , but please , NO ELECTRONICS o 3

Cheers.

42za said:

Yes this would be interesting , but please , NO ELECTRONICS o 3

Click to expand...

Agreed. Electronics would only lower it's intrinsic value, and longevity.

Digging this one up because these Leicas have intrigued me ever since I first saw them. I am fascinated with their construction and I wonder how the x42s compare to other Leica binoculars of more recent production. I understand that they are a 20 year old design. My Leicas are a 2014 UV HD 10x32, a 2016 UV HD+ 8x32 and a 2020 UV HD+ 7x42. Are there any owners who can comment on in what respects they differ from the ones mentioned above? CA for example. Any comments are much appreciated.

Hi JA,

For the details of the Ultravid optical construction, see posts #19 and 21 at: https://www.birdforum.net/threads/what’s-your-favorite-7x42-binoculars.379534/

As can be seen, both have:
• the same pattern objective, and;
• Schmidt-Pechan prisms.
The main differences are necessarily in the eyepiece area.

The Ultravid was introduced in 2003 as the BR version. The 2007 HD version added HD glass to the objective,
and the 2015 HD Plus uses Schott glass for the prisms.
As far as we know, the Duovids introduced in 2002 have neither HD or Schott glass (nor perhaps as sophisticated coatings).

In terms of the particulars of the optical performance of the Duovid, much of what little is generally known is in the links in this thread.


UV HD 8x42 and DV 8+12x42 (not to scale):



And in relation to the 2016 Noctivid:

henry link said:

Compared to the Ultravid there is an obvious change in the Noctivid eyepiece design: the addition of a negative field lens just behind the prism visible in the cutaway below. A negative element in that position ought to reduce off-axis aberrations compared to the 5 element/3 group Ultravid eyepiece.

There is a similar negative field lens (which Nikon refers to as a field flattener) in the Nikon HG, EDG and SEs along with a similar arrangement of six elements in four groups. The Zeiss SF also has a similar negative field lens combined with three cemented doublets.

Click to expand...

NV 10x42:



John

jafritten said:

Are there any owners who can comment on in what respects they differ from the ones mentioned above? CA for example.

Click to expand...

I only have the 10 / 15x50 and can‘t say much about the x42 model, but I think the story is probably not much different.

As has been pointed out, this is an older design and has no ED glass, and optical parameters such as eye relief and FOV are not any more what you would expect today from a top binocular. CA is quite prominent, esp. in the 15x position, but also with 10x, the image is miles apart from an Ultravid in terms of color correction. Plus, the Duovid is heavy compared to its Ultravid siblings. Central sharpness and image brightness are good, but not as good as in UVHD+.

I consider the Duovid a collector’s item nowadays. It still impresses with its excellent workmanship and mechanical precision.

Canip

For about three years now i use the 8-12x42 with great pleasure and joy. I can only compare it with my other phenomenal Leica, the little Ultravid 8x30 HD. Im apparently not sensitive to CA because in both binoculars i dont notice it. Nice sharp and warm saturated colors is both bins. The smaller Ultravid seems sometimes to be a tad brighter, so the 32 performs a little bit better than the 42. So i can imagine that if you would compare the Duovid side by side to a later 42 model with updated coatings (UVHD, UVHD+ and Noctovid) you will see the difference. If you use the Duovid on itself without comparing it directly to other glass IMHO i think you will still be impressed by the Leica image quality.

I dont wear glasses so i dont have issues with eye relief. It's a bit of a heavy bin, but as you can see on the pictures of John there is a lot of glass inside.

For me it's a glass i use on a daily basis when i'm on a long trip because i can use two magnifications in one binocular and therefore i have to carry less binoculars with me. It's the perfect glass to watch raptors. Also when at home the Duovid stands next to the window in 12x modus, ready to detect anything far away. Im very impressed with the optical design and build quality. It's an underrated instrument IMO and still very usable on a day to day basis but because of it's specific design its a compromise in weight, FOV etc.

As a matter of fact, because of this tread, im gonna take it with me today for a long walk on the beach and im hoping to spot some seals with it in 12x modus

Canip said:

I only have the 10 / 15x50 and can‘t say much about the x42 model, but I think the story is probably not much different.

As has been pointed out, this is an older design and has no ED glass, and optical parameters such as eye relief and FOV are not any more what you would expect today from a top binocular. CA is quite prominent, esp. in the 15x position, but also with 10x, the image is miles apart from an Ultravid in terms of color correction. Plus, the Duovid is heavy compared to its Ultravid siblings. Central sharpness and image brightness are good, but not as good as in UVHD+.

I consider the Duovid a collector’s item nowadays. It still impresses with its excellent workmanship and mechanical precision.

Canip

Click to expand...

Thank you very much, Canip. Much appreciated.

Thotmosis said:

For about three years now i use the 8-12x42 with great pleasure and joy. I can only compare it with my other phenomenal Leica, the little Ultravid 8x30 HD. Im apparently not sensitive to CA because in both binoculars i dont notice it. Nice sharp and warm saturated colors is both bins. The smaller Ultravid seems sometimes to be a tad brighter, so the 32 performs a little bit better than the 42. So i can imagine that if you would compare the Duovid side by side to a later 42 model with updated coatings (UVHD, UVHD+ and Noctovid) you will see the difference. If you use the Duovid on itself without comparing it directly to other glass IMHO i think you will still be impressed by the Leica image quality.

I dont wear glasses so i dont have issues with eye relief. It's a bit of a heavy bin, but as you can see on the pictures of John there is a lot of glass inside.

For me it's a glass i use on a daily basis when i'm on a long trip because i can use two magnifications in one binocular and therefore i have to carry less binoculars with me. It's the perfect glass to watch raptors. Also when at home the Duovid stands next to the window in 12x modus, ready to detect anything far away. Im very impressed with the optical design and build quality. It's an underrated instrument IMO and still very usable on a day to day basis but because of it's specific design its a compromise in weight, FOV etc.

As a matter of fact, because of this tread, im gonna take it with me today for a long walk on the beach and im hoping to spot some seals with it in 12x modus

Click to expand...

Thank you, Thotmosis. I am rather sensitive to CA, not overly so, but I think that could spoil it for me. Still, if I could get hold of one for a reasonable price, I'd probably go for it. I'm curious as to how other owners rate their colour correction which is my main concern here.

John A Roberts said:

nor perhaps as sophisticated coatings

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A very important point. Thank you for mentioning that, John.