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A few quick thoughts, 7X35 vs. 8X32 (1 Viewer)

There is always a tradeoff when it comes to focal length ratio. A longer focal length helps to decrease CA, but results in a longer instrument.
For a binocular this is a drawback maybe more than for a telescope or spottingscope(which you have on tripod anyway), because it contributes to place the center of weight further from the face.
And while a long refractor of f/11 results in significant less CA than one of f/5 the difference is lesser if we compare with binoculars. Here we are talking about something like f/5 vs f/4, or f/4 vs f/3,5. I don't know how big the perceived difference in CA then is.
Personally I am obviously pretty insensitive to CA when I never react about it with binoculars at normal handoldable magnifications. But I clearly see it with short focal ratio non-ED refractors when magnification is higher.
 
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Great review and write-up - but then it's right in my confirmation bias wheelhouse!

As I've written before, I'm a mid-sized binocular fan, and over the last twenty one years have primarily used an 8x32BN, 8x32BR and, currently, an 8x32HD. I wanted to love the 7x35 Retrovid, but alas its several shortcomings (for me) were a bridge too far. I'm a 7x fan (I used a Swaro SLC 7x30 from 1997-2002), and I dearly wish Leica would make a 7x35 (or 7x32) binocular with armoring, waterproofing, comfortable focus knob, twist-up eyecups, moderately fast focus, and factory supplied objective covers. Since that will likely never happen, the 8x32 is my compromise... but a fine "compromise" it is! I have no need for any other binocular.
 
@Mac308

For sure.

If had to choose a single do-everything binocular, the 32 mm Ultravid would be the one without question — at least for me.

For those who don't need longer eye relief, I can't think of anything that offers a better combination of form factor, optical performance, feel, finish and build quality. They're just an absolute pleasure to carry and to use.
 
Another way of thinking about this, is that magnification is the ratio of the focal length of the objective (including the prisms),
divided by the focal length of the eyepiece.

The use of a physically longer distance for a given focal length, often minimises various aberrations - including CA -
that are associated with physically more compact/ optically more complex designs.

By way of illustration, compare two very physically different, though both optically well regarded 7x42’s:
• the notably compact Leica Ultravid at 141 mm (5.6”) long, and;
• the optically relaxed Zeiss Dialyt at 190 mm (7.5”) long (the image being from Arek at Allbinos).

View attachment 1542975


And in terms of optical construction, the 7x42 Ultravid compared to the 8x56 Dialyt (there’s no similar image for the 7x42 version) *


View attachment 1542976

As can be seen, the Ultravid has a 4 lens objective (including the focusing lens), verses the simpler two lens Dialyt.
The Ultravid also uses the physically shorter 6 reflection Schmidt-Pechan prism, verses the 4 reflection Abbe-Koenig one of the Dialyt **

Looking at the images, the physical length of Dialyt objective/ prism assembly is essentially the same as the whole body of the Ultravid!
(Note on the Dialyt the location of the strap loop relative to the rear prism face; and the X behind the prism indicating the objective focal point.)

The Dialyt also differs in being an external focus design (focusing by moving the entire eyepiece as one unit). That helps to minimise complications
associated with having a seperate focusing lens, moving back and forth between the objective lenses and the prisms.


* The 7x42 Dialyt differs from the 8x56 version, in having a more complex eyepiece of 4 elements in 3 groups (in a 1, 2, 1 configuration).
See the discussion and images at: Zeiss Dialyt 6x42B - Binoculars - Cloudy Nights
especially posts #17 and 20.

** As a trade-off for their physical compactness, S-P prisms have inherent optical complications not found with with A-K prisms.
See post #2 at: Roof Prisms Used in Binoculars


John
Exactly. I would bet the Dialyt even without HD glass has less CA than the UVHD+. Here are some other explanations of F Ratio and CA.

"Just decreasing the aperture does not decrease chromatic aberration. I am assuming you are talking about a refractor since that is the type of telescope which suffers from chromatic aberration (CA).

It is the focal ratio that can impact CA the most with a given lens system. If you decrease the aperture of a refractor but keep the focal length the same, you will increase the focal ratio, which will reduce the visible CA. The focal ratio represents the slope or angle of the light cone. As the ratio gets larger (often called “slower”), the light cone becomes less steep, meaning that the focal plane over a range of wavelengths is thicker.

In cheaper refractors, this is often done by installing a baffle in the middle of the optical tube that is narrower than the light cone for the objective lens. The baffle shrinks the effective aperture and increases the focal ratio, reducing the CA, among other things. The greater focal ratio increases the tolerance of focus over a wider range of wavelengths. So CA is reduced, plus the overall image seems more in focus. Plus, other aberrations and maladjustment (such as bad collimation) are basically masked to a certain extent by the increased focal tolerance.

As some real life examples, I have taken telescopes labeled as 60mm (aperture) telescopes with a focal ratio of 11 (f/11) and measured the stopped down effect of their baffles (by the way, quality refractors also use baffles, but do not make them smaller than the light cone to constrict the light, rather, they are at the edge of the light cone to help prevent off axis light reflections). What I discovered was that the telescopes labeled as having a 60mm aperture were actually working as a 45–50mm telescope. That means instead of f/11, they were operating at f/14.67 to f/13.2."

"Lenses work because light passing from one medium to another at an angle is bent (refracted) depending on the angle at which it crosses the boundary and the difference in refractive index between the two materials. However, different wavelengths of light are refracted differing amounts. This is a property of glass called dispersion. This is clearly seen when white light passes through a wedge of glass (a prism):

main-qimg-8dec3dd2872f287b5b638a62cbf8d5c0-pjlq

White light is separated into its component colors. Unfortunately, lenses also act like prisms; as a result different colors focus at different points:

main-qimg-08dabe590602c91f05abfb4818bb3110

Long focal-length lenses have very slight curvature, which reduces the prism effect. before the invention of the achromatic lens (c. 1758), astronomers built refractors with focal lengths of over 100 feet to minimize the chromatic aberration.

main-qimg-eb77bb2c4cf986f4fa1a29be29981ab7-pjlq

Achromatic lenses use two optical elements: a positive lens of a low-dispersion glass, and a weak negative lens of high-dispersion glass. The high-dispersion negative element is designed to reverse the spread of the colors without neutralizing the magnifying power of the lens.

main-qimg-fb343ed894932ee5984f4255bb6cda73
 
@Mac308

For sure.

If had to choose a single do-everything binocular, the 32 mm Ultravid would be the one without question — at least for me.

For those who don't need longer eye relief, I can't think of anything that offers a better combination of form factor, optical performance, feel, finish and build quality. They're just an absolute pleasure to carry and to use.
The 32 mm UVHD+ doesn't work for me, and I don't wear glasses. The eye cups are too short for the ER, making them floaters. I have shallow eye sockets though, so they may work for some people.
 
One thing I did want to mention was the differences in exit pupils between the two.

The 7X35 Trinovid below :

IMG_1693.jpeg


That one would probably still give Swarovski a run for their money...

To the BEAUTIFUL representation of what an exit pupil can be of the 8X32 UVHD+:

IMG_1688.jpeg


Which is literally PERFECT!
 
One thing I did want to mention was the differences in exit pupils between the two.

The 7X35 Trinovid below :

IMG_1693.jpeg


That one would probably still give Swarovski a run for their money...

To the BEAUTIFUL representation of what an exit pupil can be of the 8X32 UVHD+:

IMG_1688.jpeg


Which is literally PERFECT!
Interesting and nice pictures. Does the 7x35 Trinovid show more glare than the 8x32 UVHD+?
 
One thing I did want to mention was the differences in exit pupils between the two.

The 7X35 Trinovid below :

IMG_1693.jpeg


That one would probably still give Swarovski a run for their money...

To the BEAUTIFUL representation of what an exit pupil can be of the 8X32 UVHD+:

IMG_1688.jpeg


Which is literally PERFECT!

I like the pitch black surrounding of the exit pupil of UVHD+!
 
If forced to name my favorite binocular reviewer on Birdforum, Chuck would most likely be it, or certainly top 2 or 3. So it is with some trepidation that I charge in to this conversation.

I‘ve owned the 735 Retro for a week. I've written of an unrequited lust from seeing my very first roof prism binocular, a Lietz Trinovid in an optics shop in Hanover, NH in 1970. They were just gorgeous, the view mind boggling. Just out of the military, newly married, hoping to start a career, with no money to spare, I thought "some day, I'll own this binocular."

In the hand, to the eye, these are as beautiful as I remember. This kinda Steve Jobs approach - wrap the functionality of a thing into a beautiful package, that brings joy just to look at, own. For me, these promise that.

Im not sure where Chuck's weight chart came from. I checked those numbers against B&H, as well as the manufacturers themselves. They're a bit different. Perhaps he weighed them. I did. Well, I weighed 2. My NL832 with RYO, ocular and objective covers all on board and the Retros, naked, (no carry strap or covers) weighed the same!

Chuck compared the Retro's FOV with UVHD+832 and commented he didnt notice much difference, using the factory published data @ 1000 yds(?). But 12' becomes 1.2' at 100, more like where I bird with an 8 or 10X bino, so not surprising. The NL 832 real FOV combined with its 65 AFOV does provide I think, a nicer more open view. That's a plus for the Swaro.

The focuser on the 735 I received was not the slickest mech I've experienced. I'm usually not bothered by slower focusers, prolly cause I'm used to them, but the effort required to move the focus knob on this example combined with the slower focus was not to my liking. I found it hard to find the sweet spot having to push so hard while needing to rotate so much to find it. The NLs win here, against this sample, easily.

The optical quality, in the center of the view, the only region I actually care about, was very close between these two. What was missing, (I know this will be controversial, and I bet Chuck will get it), the optical negative, is 7X. The difference in the appearance of this autumn's herd of Teal, Shovelers, Wigeons, Pintails swimming about, was small enough. But when I focused on some tight details with a bit of texture at 50 yards, I first thought the Retros weren't as sharp, clear. After a bit, I began to realize it was the difference between 7 and 8X. Not terribly significant, but it was there. As my birding is waterfowl, shore birds, raptors, I love 10X. Context matters. That is beginning to change after last summers focus on slow birding in dense forests searching for the smaller birds found there. I was sort of thinking these might be the thing for that role. Compared against my VP825 for that? Not so sure. Today, for migrating waterfowl against the 832 or 1042? The image is good, not better. The package?

I wondered about the 5mm exit pupil of the 735 vs the 4 of the 832. Against a pale grey 5 story concrete wall with fading blue sky above, mid afternoon, I do think the Leica was a tad brighter. I'd love to see how it prevails peering into the overhanging grasses that cover the curved mud bank mid tide where a bit of light gathering helps find a scurrying Ridgeway Rail..

Many have written here about depth of focus and how 7s are superior in this regard. I spent some time going between these, my 8s and 10s staring out the window at stuff near, 15’ or so, and further out to 45 yards. Peering out at Morning Glory and Passion flower vines, my neighbors roof, the Kaiser wall and a California Buckeye, there was lots of stuff at varying distances small and large. If there was a material difference in depth of focus, I couldn't see it. But to fine tune focus I had to fight the wheel.

Re glare, I saw glare in the Retros, the same as I did in my NLs looking at a place where there was glare to be seen. And like with the NLs, I didn't stick around to admire it, I changed my viewing position, changed my hold, checked if my head was erect, noticed whether the ocular was up against my glasses or tipped away. Whatever was required, glare was managed in both.

CA? Nah, nadda, zip, please.

Ergonomics? This was probably the decider for me. While I love looking at the Retro, its optics are good… enough, it still has to handle. And this for me was its shortcoming. My hands wanted more room and one less sharp object, (the strap boss) to deal with. The focuser was a drag, required too much moving about to find leverage that wouldn't move the binocular. In this comparison, with this sample, the NL won hands down. Could I imagine it might become something I'd grow to enjoy with more time? Perhaps. I'd need to change where and what I bird for though. Would I rather have the $1200. in my pocket? Well there’s other stuff to try.

Back to Chuck. I now need to get my hands and eyes on the UVHD+832. Will it work with my new eyeglasses? What might it do that compliments or betters what I already own and have bonded with?
 
When baffling is done as well as that 8x32 Leica the size of the exit pupil doesn't matter at all for glare resistance. It's only when the baffling is ineffective that a large exit pupil may come to the rescue, provided the eye's pupil stays well centered so its edge doesn't wander beyond the exit pupil edge.
 
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If forced to name my favorite binocular reviewer on Birdforum, Chuck would most likely be it, or certainly top 2 or 3. So it is with some trepidation that I charge in to this conversation.

I‘ve owned the 735 Retro for a week. I've written of an unrequited lust from seeing my very first roof prism binocular, a Lietz Trinovid in an optics shop in Hanover, NH in 1970. They were just gorgeous, the view mind boggling. Just out of the military, newly married, hoping to start a career, with no money to spare, I thought "some day, I'll own this binocular."

In the hand, to the eye, these are as beautiful as I remember. This kinda Steve Jobs approach - wrap the functionality of a thing into a beautiful package, that brings joy just to look at, own. For me, these promise that.

Im not sure where Chuck's weight chart came from. I checked those numbers against B&H, as well as the manufacturers themselves. They're a bit different. Perhaps he weighed them. I did. Well, I weighed 2. My NL832 with RYO, ocular and objective covers all on board and the Retros, naked, (no carry strap or covers) weighed the same!

Chuck compared the Retro's FOV with UVHD+832 and commented he didnt notice much difference, using the factory published data @ 1000 yds(?). But 12' becomes 1.2' at 100, more like where I bird with an 8 or 10X bino, so not surprising. The NL 832 real FOV combined with its 65 AFOV does provide I think, a nicer more open view. That's a plus for the Swaro.

The focuser on the 735 I received was not the slickest mech I've experienced. I'm usually not bothered by slower focusers, prolly cause I'm used to them, but the effort required to move the focus knob on this example combined with the slower focus was not to my liking. I found it hard to find the sweet spot having to push so hard while needing to rotate so much to find it. The NLs win here, against this sample, easily.

The optical quality, in the center of the view, the only region I actually care about, was very close between these two. What was missing, (I know this will be controversial, and I bet Chuck will get it), the optical negative, is 7X. The difference in the appearance of this autumn's herd of Teal, Shovelers, Wigeons, Pintails swimming about, was small enough. But when I focused on some tight details with a bit of texture at 50 yards, I first thought the Retros weren't as sharp, clear. After a bit, I began to realize it was the difference between 7 and 8X. Not terribly significant, but it was there. As my birding is waterfowl, shore birds, raptors, I love 10X. Context matters. That is beginning to change after last summers focus on slow birding in dense forests searching for the smaller birds found there. I was sort of thinking these might be the thing for that role. Compared against my VP825 for that? Not so sure. Today, for migrating waterfowl against the 832 or 1042? The image is good, not better. The package?

I wondered about the 5mm exit pupil of the 735 vs the 4 of the 832. Against a pale grey 5 story concrete wall with fading blue sky above, mid afternoon, I do think the Leica was a tad brighter. I'd love to see how it prevails peering into the overhanging grasses that cover the curved mud bank mid tide where a bit of light gathering helps find a scurrying Ridgeway Rail..

Many have written here about depth of focus and how 7s are superior in this regard. I spent some time going between these, my 8s and 10s staring out the window at stuff near, 15’ or so, and further out to 45 yards. Peering out at Morning Glory and Passion flower vines, my neighbors roof, the Kaiser wall and a California Buckeye, there was lots of stuff at varying distances small and large. If there was a material difference in depth of focus, I couldn't see it. But to fine tune focus I had to fight the wheel.

Re glare, I saw glare in the Retros, the same as I did in my NLs looking at a place where there was glare to be seen. And like with the NLs, I didn't stick around to admire it, I changed my viewing position, changed my hold, checked if my head was erect, noticed whether the ocular was up against my glasses or tipped away. Whatever was required, glare was managed in both.

CA? Nah, nadda, zip, please.

Ergonomics? This was probably the decider for me. While I love looking at the Retro, its optics are good… enough, it still has to handle. And this for me was its shortcoming. My hands wanted more room and one less sharp object, (the strap boss) to deal with. The focuser was a drag, required too much moving about to find leverage that wouldn't move the binocular. In this comparison, with this sample, the NL won hands down. Could I imagine it might become something I'd grow to enjoy with more time? Perhaps. I'd need to change where and what I bird for though. Would I rather have the $1200. in my pocket? Well there’s other stuff to try.

Back to Chuck. I now need to get my hands and eyes on the UVHD+832. Will it work with my new eyeglasses? What might it do that compliments or betters what I already own and have bonded with?
Nice review. I have tried 7x many times, and they never did it for me either. 7x just seems too weak. I have settled on 8x as the best compromise.
 
When baffling is done as well as that 8x32 Leica the size of the exit pupil doesn't matter at all for glare resistance. It's only when the baffling is ineffective that a large exit pupil may come to the rescue, provided the eye's pupil stays well centered so its edge doesn't wander beyond the exit pupil edge.
Good Point! Allbinos found the Leica UVHD+ 8x32 o have perfect baffling also as shown by the pictures below. Most Leicas seem to be well baffled, and they control glare very well. The 7x35 Retrovid is the first Leica I have seen with reflections like Chuck shows in his pictures.

724_leica_ol.jpg725_leica_op.jpg
 
We used to get the Eddie Bauer catalog and drool all over the cool, rich man’s gear. Eddie Bauer catered to the wealthy outdoorsman and the catalog was full of all that high end gear. That’s where I first saw the old Leitz Trinovid roof prism binoculars. Wow! They looked so futuristic and Bauer’s write up made we want one so bad.

Interesting to know how others became aware of the famous brands/models of the past! Here in the UK Leitz was acknowledged as one of the foremost optical manufacturers of that era, and I think they (or their dealers) twigged that birders (or birdwatchers as they were called in those days) were a potential market for their binoculars pretty quickly. But the Trinovids were pretty costly (£444 for a 10x40 in 1985 would be £1,314 today, that's not far off what a 10x40 Retrovid costs now) so although always admired, most birders chose something else. The real iconic birder binoculars from Leica, at least in the UK, were the later Trinovid BA/BN series that had all the features of a modern binocular (fully multi-coated, phase coated, twist-up eyecups, fully waterproof).

I had the opportunity to look through a 10x40 Leitz (rubber armoured) a few years back and thought it was very good for what it was (non-phase coated etc) and in particular, handled and pointed beautifully. I think the x40 models fit my hands better than the 7x35 which is almost too small. It's amazing how Leitz got so many things right close to 60 years ago.

I wonder just how good optically they could have made the Retrovids. The original Trinovids were the best binocular Leitz could produce economically, the Retrovids definitely aren't (and some would say the current Trinovids aka Third Tier Trinovids aren't really worthy of bearing that name).
 
Even some binoculars with reputations for poor glare resistance can show a nice dark interior like the Leica 8x32 in the photo if the eye is positioned carefully enough. The 8x42 Swaro NL is an example. If the eye is too far from the eyepiece there is considerable exposure to glare at the NL's exit pupil edge. Move the eye just close enough to the eyepiece and the interior next to the exit pupil will become about as effectively baffled as the Leica 8x32.
 
When baffling is done as well as that 8x32 Leica the size of the exit pupil doesn't matter at all for glare resistance.
Presumably Swarovski et al could baffle or otherwise blacken the areas adjoining the exit pupil just as effectively - it's not possible that doing so is beyond their capabilities, nor that designers and other optical experts could fail to note reflections and other extraneous stray light.

The question is - why haven't they?
 
Presumably Swarovski et al could baffle or otherwise blacken the areas adjoining the exit pupil just as effectively - it's not possible that doing so is beyond their capabilities, nor that designers and other optical experts could fail to note reflections and other extraneous stray light.

The question is - why haven't they?
I have heard that additional baffling would affect the ease of view in the EL. Swaorvki prides themselves on easy eye placement and the ability to move your eyes around in the eyepiece. It could be the same case with the NL.
 
Could be that Swarovski thinks the NL's narrow pupil sweet spot for glare is good enough (it has been good enough for me since I found it, but obviously not everyone does find it.) I've noticed since then that almost all binoculars will show some glare if the eye is positioned too far from the eyepiece, but some have wider pupil sweet spots than others, so they get fewer complaints. Checking about 12 of my binoculars that I remembered as being good against glare just now I found that only one was truly glare free in the test setup I used for any pupil distance from the eyepiece: a Canon 10x32 IS.
 
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Whilst I still drool at those early Trinovids ( I have a 10 x 40B in my reduced collection ) and don't really need another binocular, 11 is enough, I would be all over a 7 x 35 Ultravid HD+ in a heartbeat if such a thing came on the market AND in Silverline.
My 8 x 32 Victory FL still pleases me immensely and x 7 is catered for with a 7/42 Dialyt T*P*, whilst I still fret over not purchasing a Leitz 7 x 35 Trinovid when it was traded in - the view was, well, sumptuous.
So, whilst not really partaking in any fantasy binocular discussions, a Leica as described above would have me heading out in the car, credit card primed.
 
Whilst I still drool at those early Trinovids ( I have a 10 x 40B in my reduced collection ) and don't really need another binocular, 11 is enough, I would be all over a 7 x 35 Ultravid HD+ in a heartbeat if such a thing came on the market AND in Silverline.
My 8 x 32 Victory FL still pleases me immensely and x 7 is catered for with a 7/42 Dialyt T*P*, whilst I still fret over not purchasing a Leitz 7 x 35 Trinovid when it was traded in - the view was, well, sumptuous.
So, whilst not really partaking in any fantasy binocular discussions, a Leica as described above would have me heading out in the car, credit card primed.
A 7x35 Ultravid HD+ wouldn't be much different than the 7x35 Retrovid. There is not a lot of noticeable difference in Leicas between the Trinovid BN, Trinovid, UVHD and UVHD+. I had the Retrovid 7x35 the same time I had the UVHD+ 7x42 and when I compared them there honestly wasn't a hill of beans difference between the two. You can compare the older Leica Trinovid 8x32 BN and the UVHD+8x32, and you won't notice much difference outside the fact that the UVHD+ will be a tad brighter.
 

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