Ultravid comparison? (1 Viewer)

[elkcub]

I think there is a bit of confusion.

When I first heard Leica say that they had put in rectilinear distortion on purpose, I thought that they were pulling a fast one. However, the presence of rectilinear distortion in an optic is indeed a feature and not a flaw, and incidentally is unconnected with curvature of the field. The optical designer can completely correct for either angular magnification distortion or rectilinear distortion, but not both. The former is more important for astronomy and the latter for birding. In practice the designer reaches a compromise. Hopefully someone can give a simple explanation for angular magnification distortion but its presence leads to objects looking stretched.

Leif,

By rectilinear distortion I assume you mean barrel or pin cushion effects. For whatever reason Leica decided to over-emphasize pin cusion effects. They have a perfect right to do that, of course, but by the same token it's a salient selection factor. Personally, from what I've seen they have the tradeoffs a bit wrong.

I'm not expert on visual motion and induced motion sickness, but it would be safe to say that no binocular is immune from causing some folks a problem. My wife gets dizzy just holding a steady view for a few moments. I can follow birds in flight for a long time with no problem. Some of this comes down to becoming familiar with the cue changes induced by one's personal optical tools, which is what practice and experience is all about.

Hmmm, is it possible that Swarovski and Zeiss customers develop a different set of expectations than Leica owners? The companies build their customer bases by training (er, conditioning) their buyers to see things their way? It's a tribute to human adaptability or smart marketing. :bounce:

-elk

 

[Leif]

Oops, my sincere apology for addressing you as Henry; which also motivates me here and now to apologize to Henry. Sorry, Henry, for using your name! I feel better now. Thanks.

Arthur, my confusion relates to your statement: "... the 'problem' is the inability of a spherical lens to focus everything in a plane on the same plane." Why is this a problem? Generally speaking, spacially located points at a uniform radial distance equal to the eye's (momentary) focal distance tend to be in focus on the spheriod retinal surface, particularly the narrow foveal area. (The eyeball is not exactly a sphere.) All points on a flat surface perpendicular to the line of regard do not appear in focus in normal vision, i.e., because distance increases with off-axis angle. So why would one want to design a binocular to keep everything in focus on a flat surface? Would that not introduce perceptual problems of its own?

-elkcub

In practice the eye is a very poor optic but the brain creates the illusion of a high quality image. In practice we tend look on centre, but I for one usually see the off centre image via peripheral rather than direct vision. Things such as field curvature tend not to be obvious (unless marked) - to me anyway - but with time they become noticeable, and they detract from the overal feel of the image. I seem to think that, like distortion, field curvature becomes apparent when panning. Maybe it leads to a slight change in image size?

 

[Pileatus]

I'm still interested in hearing from someone who can explain what, if any, tradeoffs were made in the SE. To my eyes, the SE has almost no pincushion or barrel distortion, so I'm wondering if anyone can explain what Nikon sacrificed to accomplish that.

Also, what exactly is Leica's argument for introducing pincushion and why is it called a "feature"? In a forest environment, I find the bending of trees rather distracting.

John

 

[Leif]

I'm still interested in hearing from someone who can explain what, if any, tradeoffs were made in the SE. To my eyes, the SE has almost no pincushion or barrel distortion, so I'm wondering if anyone can explain what Nikon sacrificed to accomplish that.

Also, what exactly is Leica's argument for introducing pincushion and why is it called a "feature"? In a forest environment, I find the bending of trees rather distracting.

John

I addressed that in my posting earlier on. I am sure that most birders do not want rectilinear distortion.

 

[Leif]

Leif,

By rectilinear distortion I assume you mean barrel or pin cushion effects. For whatever reason Leica decided to over-emphasize pin cusion effects. They have a perfect right to do that, of course, but by the same token it's a salient selection factor. Personally, from what I've seen they have the tradeoffs a bit wrong.

I'm not expert on visual motion and induced motion sickness, but it would be safe to say that no binocular is immune from causing some folks a problem. My wife gets dizzy just holding a steady view for a few moments. I can follow birds in flight for a long time with no problem. Some of this comes down to becoming familiar with the cue changes induced by one's personal optical tools, which is what practice and experience is all about.

Hmmm, is it possible that Swarovski and Zeiss customers develop a different set of expectations than Leica owners? The companies build their customer bases by training (er, conditioning) their buyers to see things their way? It's a tribute to human adaptability or smart marketing. :bounce:

-elk

Yes pin cushion and barrel distortions are examples of rectilinear distortion.

I agree with your comments on companies 'conditioning' customers. I am sure that marketing 'trains' some people to think that what they have is the best. I find it amusing that some people will wow and coo over binocular X, but then when Y is introduced, they start seeing things wrong with X.

Also I think it's fair to say that what irritates one person, doesn't bother another. Some people might notice a drop in contrast, or chromatic aberration, or distortion, and others might not. It seems to be a question of taste. The optical designers task seems to be to try and please as many people as possible within the constraints of cost, weight and bulk.

 

[Pileatus]

I addressed that in my posting earlier on. I am sure that most birders do not want rectilinear distortion.

Leif,

Actually, I don't think you did. I asked what compromises were made in the SE to virtually eliminate pincushion and barrel distortions. I don't see any mention of the SE. Since you own an SE, I thought maybe you would have an insight (no pun) on the matter.

Also, do you think rectilinear distortion is a feature or something most birders don't want? I usually accept a feature to be something positive so I'm confused by your comments.

John

PS
How's the FL treating you?

 

[elkcub]

Okay, here's a direct quote from Leica that might help:

"... And here is another example of Leica optics in the service of the user; in order to give the viewer a natural impression of the view when the binocular is turned from side to side, for instance in sweeping an area for wildlife, all binoculars are designed with a slight pin-cushion distortion. If you sweep the landscape with a fully distortion-free binocular, you will get the impression that you are looking at a rotating globe. The perception-based "globe effect" is prevented by a precisely compensating correction. You should test the results of all these efforts towards optical brilliance yourself..." Leica: The Program, Fascination and Precision, pg.97-98, c. 1999.

They refer to pin-cushion as a "distortion" themselves, but design in more as a correction. The moral is that more of a bad thing can sometimes be GOOD. Hmmmm, that reminds me I'd better go and vote now.

-elkcub

:news:

 

[Bill Atwood]

I'm not expert on visual motion and induced motion sickness, but it would be safe to say that no binocular is immune from causing some folks a problem. My wife gets dizzy just holding a steady view for a few moments.

I've never become ill from using binoculars. HOWEVER, all this blather about rectiflatlinearpinbarrelcushion distortion is driving me :hippy: :hippy: :hippy:

 

[Leif]

Leif,

Actually, I don't think you did. I asked what compromises were made in the SE to virtually eliminate pincushion and barrel distortions. I don't see any mention of the SE. Since you own an SE, I thought maybe you would have an insight (no pun) on the matter.

Also, do you think rectilinear distortion is a feature or something most birders don't want? I usually accept a feature to be something positive so I'm confused by your comments.

John

PS
How's the FL treating you?

John: As I explained in my earlier posting, I too think that most birders do not want rectilinear distortion. As I also explained, the designer has to choose between rectilinear distortion or angular magnification distortion. I presume that the SE has angular magnification distortion. (I seem to recall seeing it too, but not having my SE to hand I can't check.)

Now in practice I think that it is also possible to introduce rectilinear distortion that is nothing to do with removing angular magnification distortion and is more to do with reducing costs. This presumably would be most evident on cheap instruments.

I happen to think that the SE is, optically, just about perfect, or at least as close as anything gets at the present time. The slight tendency to black outs is the one failing IMO. The stiff focus wheel though is very annoying and most other users do report that problem. For example several people on another forum have two and both are stiff. So Nikon could improve the focus, but they won't.

The FL is excellent and the image really is quite something especially the high contrast and naturalness.

 

[Pileatus]

John: As I explained in my earlier posting, I too think that most birders do not want rectilinear distortion. As I also explained, the designer has to choose between rectilinear distortion or angular magnification distortion. I presume that the SE has angular magnification distortion. (I seem to recall seeing it too, but not having my SE to hand I can't check.)

Now in practice I think that it is also possible to introduce rectilinear distortion that is nothing to do with removing angular magnification distortion and is more to do with reducing costs. This presumably would be most evident on cheap instruments.

I happen to think that the SE is, optically, just about perfect, or at least as close as anything gets at the present time. The slight tendency to black outs is the one failing IMO. The stiff focus wheel though is very annoying and most other users do report that problem. For example several people on another forum have two and both are stiff. So Nikon could improve the focus, but they won't.

The FL is excellent and the image really is quite something especially the high contrast and naturalness.

Leif,

Thanks.

The SE does get a bit stiff in colder weather and Nikon should adjust for that, but I doubt they will. Since I'm not in a hurry anymore, it doesn't bother me too much to miss a bird now and then.

John

 

[Bubbs]

Has anyone out there had chance to compare the Ultravid 10x32 with the Trinovid 10x32? I would be interested to know how you thought they compared.

Dave

Dave asked a perfectly sensible, down to earth question, and was met with replies which contained the words.

1. Pincushion distortion.
2. Retilinear distortion.
3. Angular magnification distortion.
4. IMO....?
5. Natural pictorial impression.
6. IIRC.
7. Focusee.
8. Radial distance.

I could go on and on but I won't.

I have watched birds since childhood - 41 years - and I have absolutely no idea what the above words mean and I really don't want to...life is just too short.

Simply put: Do you like the feel of them and do you like them when you look at birds and other wildlife through them?

YES or NO will do!

JB.

 

[Curtis Croulet]

IMO = "In my opinion"; also often seen as IMHO, which means "In my humble opinion"
IIRC = "If I recall (or remember) correctly"

These are Internet shorthand. Here's a few others you might see in this forum:

FWIW = "For what it's worth"
BTW = "By the way"
ROTFL = "Rolling on the floor laughing"
ROTFLMAO = "Rolling on the floor laughing my a** off"
YMMV = "Your mileage may vary" (which may have no relevance in the UK; it's a disclaimer used in auto advertisements in the US).

There are many other such bits of Internet shorthand that I only see in lists of these things but never actually see in Internet postings.

 

[Bill Atwood]

I feel your pain JB.

 

[lvn600]

As someone who i relatively new to the hobby I am glad to have read this post. I just bought a new pair of roof prism swifts not wanting to spend big bucks. When looking at birds in thickets between 7 to about 25 feet they are nice and sharp but i was dissapointed when searching for eagles from a distance. I noticed that cuvature effect when panning in the distance but didn't know that this was a common effect. Fortunately i use them mostly for close up viewing.

 

[Pileatus]

As someone who i relatively new to the hobby I am glad to have read this post. I just bought a new pair of roof prism swifts not wanting to spend big bucks. When looking at birds in thickets between 7 to about 25 feet they are nice and sharp but i was dissapointed when searching for eagles from a distance. I noticed that cuvature effect when panning in the distance but didn't know that this was a common effect. Fortunately i use them mostly for close up viewing.

I suggest you experiment with the binocular IPD setting, which can be critical to achieving a superb view. If I'm viewing long distance for any period of time, I'll adjust the IPD for distance...and it makes a difference. You should be able to "eliminate" a lot of the curvature distortion by adjusting the IPD, and the rest of it can be probably be eliminated by not looking for it. The pincushion in my Leica has become totally transparent to me. I see it if I look for it; in actual use it is not a problem at all. FWIW, FL's, EL's etc. all have pincushion.

The other thing I've noticed is that if the IPD is set too "tight" (not wide enough) all sorts of minor/major distortions can crop up depending on the viewing distance. It's also important to note that the average human near IPD measurement is 3 mm less than the far IPD. The eye is quite sensitive to distance, lighting conditions keep our pupils busy, and it seems logical that our bins will need adjustment from time to time. I originally thought you could set the IPD, fix the diopter, and never worry about it again. Experience taught me otherwise.

Good luck!

John

 

[AUDIE]

Why they had to go.

Curtis,

Since you don't have much time logged on the SE you may not appreciate its beauty. Ask any SE user and they will tell you that pincushion is almost non-existent, the field is extremely sharp across a very wide "sweet spot", edges can be focused tack sharp, and the resulting view is very restful, pleasing and addictive. Yes, there are curvature "distortions" in the SE, but they are insignificant in the field.

I've used the SE for countless hours of observation and I can tell you it is one amazing piece of work. I have seen nothing comparable in overall visual quality.

I often get the impression people don't want to hear about the SE's qualities and I find that disappointing. Consumers should prod manufacturers to produce the very best and saying good things about a product seems as appropriate as commenting on the negative. It appears none of my comments, good or bad, will be accepted at face value.

Finally, I am not, nor have ever claimed to be, an optical expert. I am an end user with a pair of eyeballs that still work. I report what I see, and what I see in the SE has, so far, not been matched by any other binocular. I believe that’s called an opinion.

John

Had a pair for a year could not get used to CA, both on and off axis. The only binocular I could not hold steady,did not like to be seen out with them. They looked so naff.

 

[elkcub]

... It's also important to note that the average human near IPD measurement is 3 mm less than the far IPD.
Good luck!

John

John,

If true, is this because of the convergence of the eyes? Also — what is the definition of near and far, and is it measured with or without binoculars?

Thanks,
Elkcub

 

[Pileatus]

John,

If true, is this because of the convergence of the eyes? Also — what is the definition of near and far, and is it measured with or without binoculars?

Thanks,
Elkcub

Near and far IPD's are measured and studied using the naked eye.

I was trying to make the point that a bin setup for distance viewing will often need an IPD adjustment for close-ups (reduce the IPD). Anyone can see this by adjusting their bin for perfect long distance viewing with the images centered in both oculars. Now look at something at the minimum range of the bin. The object will not be centered in both oculars at close range, especially with widely spaced porros! IF the lens is VERY sharp across the field, the difference in image position may not be a problem, however it most likely will be. In some cases, one image is centered while the other is on the edge of the FOV! If the IPD is reduced, both images can, if there's enough IPD adjustment available in the bin, be centered in each ocular. The naked human eye takes care of this near/far disparity by adjusting itself to the situation.

The SE is a perfect example. I originally set mine up for long distance viewing and, as a result, experienced a less than perfect image at close range. The field sharpness of the SE is so good that off-centered images are very acceptable…but not totally satisfying to the brain. Setting a perfect IPD on the SE is a skill every SE user eventually masters and I originally hesitated to adjust it for any reason. Again, I believed one IPD setting would suffice for all conditions and it doesn’t.

As I was studying spider webs one day at minimum distance, I adjusted the IPD on my SE. Instantly, the view became extraordinary as the two images arrived at optical center. The SE has a low IPD setting (53 mm), which makes this adjustment effortless. People often complain about using porros at close distances, and I’m convinced most have never used one with enough IPD adjustment. Anyone who uses the SE 8X32 to study flowers, spiders, etc. will attest to the fact that it delivers a distortion-free 3D view that is stable, full of colorful details, and as easy on the eye as I can imagine.

John

 

[elkcub]

Near and far IPD's are measured and studied using the naked eye.

I was trying to make the point that a bin setup for distance viewing will often need an IPD adjustment for close-ups (reduce the IPD). Anyone can see this by adjusting their bin for perfect long distance viewing with the images centered in both oculars. Now look at something at the minimum range of the bin. The object will not be centered in both oculars at close range, especially with widely spaced porros! IF the lens is VERY sharp across the field, the difference in image position may not be a problem, however it most likely will be. In some cases, one image is centered while the other is on the edge of the FOV! If the IPD is reduced, both images can, if there's enough IPD adjustment available in the bin, be centered in each ocular. The naked human eye takes care of this near/far disparity by adjusting itself to the situation.

The SE is a perfect example. I originally set mine up for long distance viewing and, as a result, experienced a less than perfect image at close range. The field sharpness of the SE is so good that off-centered images are very acceptable…but not totally satisfying to the brain. Setting a perfect IPD on the SE is a skill every SE user eventually masters and I originally hesitated to adjust it for any reason. Again, I believed one IPD setting would suffice for all conditions and it doesn’t.

As I was studying spider webs one day at minimum distance, I adjusted the IPD on my SE. Instantly, the view became extraordinary as the two images arrived at optical center. The SE has a low IPD setting (53 mm), which makes this adjustment effortless. People often complain about using porros at close distances, and I’m convinced most have never used one with enough IPD adjustment. Anyone who uses the SE 8X32 to study flowers, spiders, etc. will attest to the fact that it delivers a distortion-free 3D view that is stable, full of colorful details, and as easy on the eye as I can imagine.

John

John,

Thanks for the clarification. Since you mentioned 3mm exactly, it sounded like someone had carefully studied the average human IPD with binoculars at near and far distances. I wanted to find out more about it.

Based on my limited experience with porros, I believe they do need more inter-ocular adjustment than roofs because of their greater spread (hyperstereo). My Nikon 8x30A makes for teriffic 3-D, for example, but at close range I do move the objectives closer together to maintain overlapped fields. Actually, I even do that with roofs, but maybe not as much. It seems to me that since the optical axes are always parallel, each eye must see off-axis images at close range. If so, that in turn would make the optical design more demanding?

Maybe someone will comment on this question.

Elkcub

 

[kabsetz]

Elkcub,

You are absolutely correct in your assessment about optical axis parrelism and the need of the eyes to look progressively more off-axis the closer you look. Likewise concerning the differences between porros (except for the rare ones with underslung prism assemblies) and roofs as well as the greater demands for eyepiece design that this places on porros if you want them to perform well at close ranges. I just measured my 10x42 SE which, for my 65mm IP setting has optical axes 130mm apart. For a Leica Ultravid 8x32, 65mm IP gives 65mm spread between the axes. Nikon x32 HG's have optical axes closer than the IPD, and Swaro EL range a little farther. It would be very simple to measure how far off-axis the image will be situated at different distances with a typical porro and a typical roof providing you view stereo with both eyes and attempt to place the image symmetrically for both eyes. I suspect that many people with a pronouncedly dominant eye will tend to place the object of interest closer to the center for the dominant eye and further off-axis for the latent eye to make close range viewing easier.

The SE is one of the few birding porros which has a large enough sweet spot to allow for satisfactory close range viewing, but as John said, even then it is much easier if you adjust the IPD in these situations. Personally, I would prefer the SE to have underslung prisms, even at the cost of reduced stereo perception. This would bring their parallax error down to the same level as it is with roofs, and would also make them easier to hold at least for me.

I suspect that one reason roof prism binoculars have gained such popularity is that a majority of people try out their prospective choices inside a store, where distances are always closer and roof prism binoculars enjoy their inherent parallax advantage to the full.

Actually, the reason for adjusting the IPD is not so much to make the images overlap better - since the effect on this is marginal - but to align the exit pupils with the pupils of your eyes. As you look closer, you progressively cross your eyes more, whereby your IPD gets narrower. I just measured the most comfortable IPD for both the SE and Leica at 3 meters distance, and for both it was down from 65 to about 62mm (the SE does not really focus that close, but even with an out-of-focus image I could determine the best IPD very easily. A three millimeter difference in parallax is almost insignificant with respect to image overlap, but proper alignment of the eye to the exit pupil is important for viewing comfort.

In theory at least, it would be possible to design a binocular where the collimation of the optical axes would adjust together with the focus. However, this would no doubt result in an exceedingly expensive and complex design.

Kimmo