Buying first new binoculars in 30 years (1 Viewer)

[AndrewC1]

I'm replacing my Zeiss 7x42 Dialyts which I purchased in 1991 or thereabouts. In the intervening years the only other binoculars that I have looked through were my wife's 10x40 Optolyths and 8x32 Opticrons.

I've been reading various posts in this forum and a lot talk about flat field v curved field of view. I'd never heard of this. Presumably my Zeiss's were curved field?

Anyway, I'm trying to understand why it matters. Who prefers what and why? Is it simply a matter of increased sharpness to the edge of the frame in flat-field lenses?

Or is there more to it?

Looking to get a x8 binocular, 8x32 or42.

 

[[email protected]]

If you have a higher budget, you can't go wrong with a Swarovski SV 8x32 or Meopta Meostar B1 Plus 8x42 which is a little heavy at 900 grams, but it is very good optically for the price and built like a tank. Both will run about $1500, but if you want to stay around $1000 I would try the Zeiss Conquest HD 8x32 but the SV and Meostar are going to be a step-up in quality, and really they are alpha. Of course, if you want the latest and "possibly" greatest, and you value a lightweight binocular there is the new Zeiss SF 8x40 for around $1800 if you want to push your budget a little higher. Also, there are the porro's like the Habicht which are very good optically and have the 3D image, but it sounds like you want an almost alpha roof and at $1800 if you shop around you could get one for that. I think with a budget of $1800 I would wait for the new Zeiss SFL 8x40 and see how the reviews are, but it sounds like it is going to pretty nice. Be aware that if you are used to the Dialyt's 7x42 an 8x32 or 8x42 will not be as bright in low light, they will be harder to hold steady, they won't have as great of DOF and eye placement will be more finicky although an 8x42 is pretty good as far as ease of eye placement. There are still some good 7x42 binoculars around if you wanted to stay with a 7x42.

 

[Murmur]

Some idea of available budget, weight and size requirements and the like would be helpful.

As Dennis has weighed in with some of his usual suspects ( ) I shall do the same and suggest Kowa Genesis 8x33, which can often be had for rather less than list price or the prices of Swaros and the like.

 

[AndrewC1]

Some idea of available budget, weight and size requirements and the like would be helpful.

As Dennis has weighed in with some of his usual suspects ( ) I shall do the same and suggest Kowa Genesis 8x33, which can often be had for rather less than list price or the prices of Swaros and the like.

Well, I was thinking of spending up to £1500 (happy to spend less!) and I am not averse to buying used. Regarding weight, upto about 800g would be about my limit. Not too bothered re size.

 

[Binocollector]

Anyway, I'm trying to understand why it matters. Who prefers what and why? Is it simply a matter of increased sharpness to the edge of the frame in flat-field lenses?

Or is there more to it?

I have a couple of flat-field binoculars but most of them were bought for astronomy where it is much preferrable to have sharp stars at the edge of the field and the middle of the field. For daytime use, birding and general nature observations I think it is much less of an issue. In fact, depending on what you are looking at, it is possible that more of the field of view is in focus with a curved field -- like when there are trees on the edge that are a little closer to you, or the ground in front of you, that is closer, while looking at something in the middle of the field that is a bit further away. While I think it is nice to have a flat field, many of the flat field binos I own, have also a narrower field of view, probably because it is easier to have a flat field, when it is not as large. Therefore, binoculars with a large field of view and a flat field are much more expensive and more difficult to make. Like the Swarowski NL Pure.
For daytime use I prefer a wide field of view over a completely flat field of view -- depending on what I am looking at. A vintage 7x35 porro with 11° FoV is my current favourite. But I go back and forth between that one and other binos.
Also -- flat field needs to be distinguished from "a field free of distortions". A flat field bino can still have things like a puncushion distortion to prevent the "globe" effect when panning but that doesn't mean that the edge of the field is blurry. I am not very susceptible to the globe effect so I don't care.
Fun fact -- I have a vintage Hensoldt pre-WWII that was build before the pincushion distortion was generally adopted to be the norm by basically all manufacturers to prevent the globe effect and that one is sharp to the edge just like a modern day bino with "field flatteners".

 

[Richard D]

The Zeiss 7x42 Dialyts were an excellent binocular for their day, and if they haven't hazed up and the mechanics are good will still hold their own with a lot of more recent binoculars.

Yes flat field is basically the curvature is adjusted so that you don't get a slightly different focus point round the edge. The edges tend to be better corrected for coma and other less desirable features hidden in that last few percent. I like flat field, but it's not the be all and end all of binoculars - I use traditional too, and after a few minutes birding don't focus on the differences.

The major improvements over 30 years have been in coatings, modern bioculars are generally a lot brighter and suffer slightly less abberations.

Top end are generally considered the Swarovski NL Pures - pretty much edge to edge sharpness and a massive Field of View, a few people do find that FoV makes them slightly more susceptible to glare under very bright conditions, but most don't find it a problem (I've yet to meet a person who does, but as a fair headsup some site users have). You might just get lucky with a used pair of 8x32 at the top of your budget, unlikely to get the 8x42s.

Sitting so close that it's as much personal preference as anything are the Zeiss SF and Swarovski EL SV's - again you'd be looking at used. If you don't mind going with traditional lugs over the fieldpro attachment you can get excellent deals on used EL SVs that are optically identical, but check they're the last model. My 8x32's and 10x32s are EL SVs and I really like them - both have a wide FoV and are optically excellent. Oh, and there's also the Leica Noctvid that has dedicated fans.

Within budget new are the Kahles Helia-S - rebadged Swarovski SLCs with a non Flat-field design but optically excellent, and made in the same Austrian factory. There's the new Japanese made Zeiss SFL's that from early feedback generally get positive comments, but they're not widely released yet.

Around the £1000 mark there are plenty of options and more manufacturers...

If you visit a few reserves and chat to other birders I find they'll generally happily swap binoculars for a bit to give you an idea of field use, it's sometimes as useful as visiting an optics shop. A lot of it is personal preference - there are few bad binoculars in the higher price brackets.

 

[Rg548]

If you can test a Leica Ultravid, and then an SF or NL Pure, you will see the difference.
My preference is the Ultravid, which is the cheapest of that bunch.
And as Dennis says, Habicht Porros are simply superb IF they work for you, try first for sure!!!
I was not overly impressed with the Pures. I'm sure they are technically the finest, but I feel no need for flat field, and just preferred the view through the Leicas. The pures, and to some extent the SF's felt a little flat and cold. I couldn't see what all the fuss was about.
This is just a personal opinion.
Some like, bright, sharp to the edges view, and this costs big money to achieve, others prefer a more 'traditional' view.
I would love a Leica Ultravid HD+, but I chanced upon some Meopta Meostars, which give a similar view, and settled with these.
With the money you will be spending, you will get great glass regardless, the rest is just personal

 

[Paultricounty]

Bonecollector summed up the flat field or curved field with all you need there. Richard D covered great choices and added some great info on the FOV personality on those choices. I’d like to ad the Kowa Genesis, a great choice as someone else here recommended, I’d second that.

The new Zeiss SFL coming out, has been mentioned (and discussed add nauseam in another discussion) but has no track record as of now, I’d say that’s a wait and see binocular, and I believe prices will come down on those not long after they hit the main stream market.

They Seem to be very interesting, but the initial price point puts it in a very tough market. For a $100-$200 more you could pick up Zeiss SF top of the line premium 32mm, that will be superior in 90+% of viewing conditions, give or take. Or a good condition used 32/42 for same or less. Why use an optically Inferior binocular that almost cost the same as the top of the line for just 10% of your viewing time. I’m not sold on these yet.

A couple of other great choices in your price consideration could be a good deal on Leica Ultravids (gorgeous class) , as well as the Nikon MHG.

Paul

 

[elkcub]

I'm replacing my Zeiss 7x42 Dialyts which I purchased in 1991 or thereabouts. In the intervening years the only other binoculars that I have looked through were my wife's 10x40 Optolyths and 8x32 Opticrons.

I've been reading various posts in this forum and a lot talk about flat field v curved field of view. I'd never heard of this. Presumably my Zeiss's were curved field?

Anyway, I'm trying to understand why it matters. Who prefers what and why? Is it simply a matter of increased sharpness to the edge of the frame in flat-field lenses?

Or is there more to it?

Looking to get a x8 binocular, 8x32 or42.

Hello Andrew, ... welcome to BF.

I take it that your 7x42 Dialyt is a T*P model, which means that it's phase corrected. If so, you already have an exceptional instrument that would be hard to improve upon. And, yes, they are definitely "curved field" as you put it. Have you had it checked out by Zeiss to determine whether it can be restored to its original condition? I did that with mine about 10 yrs. ago and they were very helpful. Of course, that was a decade ago and things may have changed. (Note: the original T* model without phase correction is considerably darker and can't be upgraded to T*P.)

With regard to "flat field" binoculars I tend to keep these and related thoughts to myself nowadays but I'll make an exception. Under normal conditions, the human eye points to objects of interest using voluntary eye-, head-, and body- rotations. The image of an object of immediate interest is placed on the retinal fovea for clearest vision. It is always true that images falling outside the fovea become progressively defocused, in part due to the eye's inherent curvature of field. Indeed, it has been shown experimentally that the perception of flatness itself is facilitated by the presence of this normal defocus gradient. So, my contention based on personal observation (and supported by those of several others) is that binoculars with field flatteners (FF) interfere with this normal perceptual process and create a cue conflict situation for the brain to resolve. The result (for those of us who react negatively) is that the observed field appears to be artificially flat, which I liken to looking at successive layers of cardboard pictures. I don't like it, I won't try to adapt to it, It bothers me, ... and as a result I have sold all binoculars that incorporate FFs.

I should also add that were I an astronomer observing the night sky at infinite distance with dark-adapted eyes, FFs might just be the ticket. But, that's not the case.

Hope I haven't made matters worse for you.

Ed

 

[Patudo]

It's worth noting that if your Dialyt is a P or P* model, it's still a extremely good binocular even by today's standards. It may however benefit from a service after thirty years' regular use - Gary Hawkins at East Coast Binocular Repairs did mine and I can fully recommend him.

Flat field, as I understand it, refers to the absence of barrel or pincushion distortion - if a grid or chequerboard was viewed through a "flat field" binocular you would expect all lines to appear perfectly straight, without the curvature that barrel or pincushion distortion gives. However, pincushion distortion is often deliberately designed to reduce what is called the "globe effect" that some (but not all) users are affected by when using optics designed to be distortion-free. Flat field, to my mind, also ought to mean a flat focal plane - explained fairly well in this link. In practice the term "flat field" tends to be used as shorthand for sharpness right to the edge.

I've been very satisfied with the flat field binoculars I've used - but it's certainly not essential for a binocular to have a flat field to offer an outstanding image. The 7x42 Dialyt (P model) still does, and so do a number of others (Leicas, Swarovski SLCs). Swarovski EL Swarovisions are probably the best known flat field binoculars - others with some degree of field flattening include Zeiss's SFs and Nikon's EDGs.

I recommend you try a number of quality binoculars alongside your Dialyt to get a feel for the different kinds of image they show you. It's very useful to have something you know intimately as a yardstick to go back and forth with.

 

[AndrewC1]

Hello Andrew, ... welcome to BF.

I take it that your 7x42 Dialyt is a T*P model, which means that it's phase corrected. If so, you already have an exceptional instrument that would be hard to improve upon. And, yes, they are definitely "curved field" as you put it. Have you had it checked out by Zeiss to determine whether it can be restored to its original condition? I did that with mine about 10 yrs. ago and they were very helpful. Of course, that was a decade ago and things may have changed. (Note: the original T* model without phase correction is considerably darker and can't be upgraded to T*P.)

With regard to "flat field" binoculars I tend to keep these and related thoughts to myself nowadays but I'll make an exception. Under normal conditions, the human eye points to objects of interest using voluntary eye-, head-, and body- rotations. The image of an object of immediate interest is placed on the retinal fovea for clearest vision. It is always true that images falling outside the fovea become progressively defocused, in part due to the eye's inherent curvature of field. Indeed, it has been shown experimentally that the perception of flatness itself is facilitated by the presence of this normal defocus gradient. So, my contention based on personal observation (and supported by those of several others) is that binoculars with field flatteners (FF) interfere with this normal perceptual process and create a cue conflict situation for the brain to resolve. The result (for those of us who react negatively) is that the observed field appears to be artificially flat, which I liken to looking at successive layers of cardboard pictures. I don't like it, I won't try to adapt to it, It bothers me, ... and as a result I have sold all binoculars that incorporate FFs.

I should also add that were I an astronomer observing the night sky at infinite distance with dark-adapted eyes, FFs might just be the ticket. But, that's not the case.

Hope I haven't made matters worse for you.

Ed

Thanks for all the information. My ownership of the Dialyts came to an unexpected sudden end, hence the need to get new bins.

 

[AndrewC1]

Hello Andrew, ... welcome to BF.

I take it that your 7x42 Dialyt is a T*P model, which means that it's phase corrected. If so, you already have an exceptional instrument that would be hard to improve upon. And, yes, they are definitely "curved field" as you put it. Have you had it checked out by Zeiss to determine whether it can be restored to its original condition? I did that with mine about 10 yrs. ago and they were very helpful. Of course, that was a decade ago and things may have changed. (Note: the original T* model without phase correction is considerably darker and can't be upgraded to T*P.)

With regard to "flat field" binoculars I tend to keep these and related thoughts to myself nowadays but I'll make an exception. Under normal conditions, the human eye points to objects of interest using voluntary eye-, head-, and body- rotations. The image of an object of immediate interest is placed on the retinal fovea for clearest vision. It is always true that images falling outside the fovea become progressively defocused, in part due to the eye's inherent curvature of field. Indeed, it has been shown experimentally that the perception of flatness itself is facilitated by the presence of this normal defocus gradient. So, my contention based on personal observation (and supported by those of several others) is that binoculars with field flatteners (FF) interfere with this normal perceptual process and create a cue conflict situation for the brain to resolve. The result (for those of us who react negatively) is that the observed field appears to be artificially flat, which I liken to looking at successive layers of cardboard pictures. I don't like it, I won't try to adapt to it, It bothers me, ... and as a result I have sold all binoculars that incorporate FFs.

I should also add that were I an astronomer observing the night sky at infinite distance with dark-adapted eyes, FFs might just be the ticket. But, that's not the case.

Hope I haven't made matters worse for you.

Ed

Thanks for all the information Ed. I no longer have the Dialyts. They were a fine binocular which I thought I would keep for the next 30 years!

 

[elkcub]

Flat field, as I understand it, refers to the absence of barrel or pincushion distortion - if a grid or chequerboard was viewed through a "flat field" binocular you would expect all lines to appear perfectly straight, without the curvature that barrel or pincushion distortion gives.

Hello Patudo,

Sorry to jump on this, but unfortunately your current understanding needs a bit of fine tuning. The easiest way to put it is that there are five so-called third-order aberrations that independently affect the image. Being "independent" means that one aberration does not functionally cause any of the anothers. The five aberrations are: Spherical, Coma, Astigmatism, Field Curvature, and Distortion.

In this instance what you described was the last aberration, Distortion, the absence of which is known to induce a disturbing visual illusion called the "globe effect" during panning (i.e., dynamic) tasks. Holger Merlitz has shown that a minimum amount of Distortion is necessary to suppress the illusion, so eliminating it entirely is not necessarily an optimal human-engineering design.

In a similar way, FFs are used to eliminate Field Curvature, so that defocus will not occur off-axis, and the image will appear "sharp from edge-to-edge." However, as discussed in post #9, my contention is that the absence of this aberration induces a static flat cardboard-image effect that some observers find very uncomfortable, hence, eliminating field curvature is also not an optimal human-engineering design.

Ed

 

[Trinovid]

I no longer have the Dialyts. They were a fine binocular which I thought I would keep for the next 30 years!

If the Dialyt was such a perfect match for you then finding another pair could possibly be the shortest path to satisfaction.
Assuming of course that they're findable.

 

[Mike Crawley]

Another forum member has these Zeiss binoculars for sale.
My partner has the same model and thinks they’re great

https://www.birdforum.net/threads/zeiss-terra-ed-32-binoculars-harness.424382/

 

[Richard D]

If the Dialyt was such a perfect match for you then finding another pair could possibly be the shortest path to satisfaction.
Assuming of course that they're findable.

They do crop up used - only discontinued in the early 2000's, but unless they're in perfect condition the service costs can be expensive - Roger Vive did an interesting review of them and costs in servicing: Zeiss 7x42 Dialyt ClassiC Review

 

[edwincjones]

AndrewC1,

My suggestion is to go to an optic shop or several that has a good selection of binoculars and pick out one the feels good to you-your eyes and your hands.
Listen to the many opinions here, have a general idea of what you want, then pick the one you bond best with.
If the majority of members here like a specific binocular then it is probably good, if they do not it is probably not;
BUT get what you like.
Just do not get too cheap or to expensive.
Between 32 and 42 mms, 32s are lighter and easier on the neck,
42s gather more light and are better for low light conditions.

edj

 

[corvid-8]

You cannot go wrong with the new Opticron Aurora 8x42 BGA VHD. Just look at the reviews on here especially by Ratal.
Must confess, a bit of a cheek, I do have a pair for sale on eBay at the moment. But they are a great binocular. Hope I have not offended the governing powers on this inclusion.

Opticron Aurora BGA VHD 8x42 Binoculars | eBay

Opticron Aurora BGA VHD 8x42 New Model. EXCELLENT + condition. RECEIPT enclosed for transfer of warranty.Bought from Opticron direct last year. cost £799. Serviced and inspected by Opticron 22/4/22.

www.ebay.co.uk

 

[dwatsonbirder]

Hi Andrew, welcome to birdforum.

Hopefully these are still available - at that price I would say unbeatable!

 

[tenex]

So, my contention based on personal observation (and supported by those of several others) is that binoculars with field flatteners (FF) interfere with this normal perceptual process and create a cue conflict situation for the brain to resolve.

This theory sounds interesting but I don't understand it yet. Wouldn't a defocus gradient due to the eye's own curvature of field still apply when gazing straight ahead through binoculars? (And wouldn't it then be curved-field models that exaggerate that gradient in a potentially odd way?) Or am I falling into the old camera-analogy trap, whereas field curvature here is a property of the whole eye-binocular system, so FFs correct for both?