I wonder if the old non-IS Canon 8x32WP is similar. I read once that it has an Erfle-design ocular. It is very well corrected for field curvature but I'd have to check for pincushion again and whether it has the "moustache-distortion". It ranks among my favourite flat-field designs. Unfortunately it has no p-coatings. Still a nice bino, pretty sharp, flat field and almost no visible CA for my eyes.For a good example of a flat field binocular eyepiece with enough straightforward pincushion to completely correct AMD check out the older Canon IS models as well as the newer 32mm models.
The result is low AMD across most of the field reversing to high AMD near the field edge.
Yes I think the photo through the srga highlighted this, lots of field curvature and blurry edges and a fair amount of pincushion distortion!Notice that the distortion in the Komz and the Kowa is not straightforward pincushion. It's mustache distortion, caused by pincushion that increases across the inner part of the field in the normal manner, but then reverses in the outer part giving a line near the field edge the appearance of a handlebar mustache. The result is low AMD across most of the field reversing to high AMD near the field edge.
The conclusions reached in the thread "Binocular Evolution II: Distortion and Curvature" about a supposed relationship between the correction of field curvature and distortion were simply incorrect. There is no relationship between the type and amount of rectilinear or angular magnification distortion and field curvature. For a good example of a flat field binocular eyepiece with enough straightforward pincushion to completely correct AMD check out the older Canon IS models as well as the newer 32mm models. To find eyepieces with even more pincushion combined with well corrected field curvature see the Televue Panoptic and naglers
It's pure coincidence that field curvature and pincushion distortion happen to be present together in that binocular. It doesn't have to be that way at all.Yes I think the photo through the srga highlighted this, lots of field curvature and blurry edges and a fair amount of pincushion distortion!
It would have been nice to hear this earlier. I don't have experience with a wide enough variety of eyepieces, so we futzed around with hypotheticals for quite some time over this.The conclusions reached in the thread "Binocular Evolution II: Distortion and Curvature" about a supposed relationship between the correction of field curvature and distortion were simply incorrect. There is no relationship between the type and amount of rectilinear or angular magnification distortion and field curvature. For a good example of a flat field binocular eyepiece with enough straightforward pincushion to completely correct AMD check out the older Canon IS models as well as the newer 32mm models. To find eyepieces with even more pincushion combined with well corrected field curvature see the Televue Panoptics and Naglers.
The question that inspired that other thread (and lingers for me now) was: if such complex distortion is actually deliberate, rather than just tending to be a consequence of field-flattening, why does it seem desirable to engineer?Notice that the distortion in the Komz and the Kowa is not straightforward pincushion. It's mustache distortion, caused by pincushion that increases across the inner part of the field in the normal manner, but then reverses in the outer part giving a line near the field edge the appearance of a handlebar mustache. The result is low AMD across most of the field reversing to high AMD near the field edge.
The Komz and the Kowa do not have a flat field however. But both have "moustache"-distortion. So it must be caused by something else.The question that inspired that other thread (and lingers for me now) was: if such complex distortion is actually deliberate, rather than just tending to be a consequence of field-flattening, why does it seem desirable to engineer?
My understanding is that it is not possible to simultaneously control all distortions/aberrations, because as you improve one, you make another worse, so it is not so much that the remaining distortions were considered 'desirable' by the engineer, more a case of these distortions being the inevitable and unavoidable consequences of other improvements that were given a higher priority.The question that inspired that other thread (and lingers for me now) was: if such complex distortion is actually deliberate, rather than just tending to be a consequence of field-flattening, why does it seem desirable to engineer?
I don't think Henry was suggesting that complex distortion was a design goal, more a design limitation to satisfy other goals.
You can get a good idea of the Fov by shining a phone torch through the eye piece of each and seeing how wide the projected circles of light are on a wall or similar.Rather interesting discussion. I just did a little more comparisons between my "skeleton bino", 6x25, 11.5° and the Komz 6x24. When looking through both they seem to have the same FoV -- the "skeleton bino" maybe being a tad wider.
To my eyes the "skeleton" J-B93 bino shows the perfect panning behaviour when it comes to the pincushion distortion -- just enough to completely eliminate rolling ball and not have "bowl" effect.
While the Komz is not as comfy to me when using.
The "skeleton" bino however has a far less sophisticated ocular design. I am not even sure how many lenses there might be, considering how short it is.
The Komz, I am pretty sure, has 5 lenses in the ocular -- at least the very similar 8x30 Komz has 5 lenses because it was even advertised as such when being sold by 3rd parties and labeled for "Bresser" or "Revue". It says "5-Linser" (5 lenses) on the bino itself.
So here is the thing though. I am beginning to think that it is just my eyes that perfectly harmonize with the "skeleton" bino more than with the Komz because I did a little "experiment" and put the lens of my smartphone camera on the ocular and then scanned the scenery through the living room window -- and when looking at the smartphone screen I could see a distinct bowl-distortion.
Now the question is of course how much distortion does the wide angle smartphone camera lens have? Does its distortion ad more pincushion so the "skeleton" bino begins to show bowl distortion which it doesn't when I actually use it?
But the Komz on the other hand had an almost perfect panning behaviour when looking at the smartphone display.
So I guess it is my eyes that harmonize better with a "standard" large pincushion distortion in EWA binos than with the "mustache" distortion which to my eyes looks like barrel distortion.