My "Ultimate" Choice (5 Viewers)

[AlanFrench]

Alan,

Binoculars do have enough power to see this.
[SNIP]
Henry

Henry,

I tried several pair here. Although there is considerable variation in "gearing," so it is difficult to compare the difference in focus between binoculars, I got the following impression...

Swarovski 7x42 SLC - slight astigmatism
Canon 12x36 IS - slight astigmatism
Fujinon 8x40 BFL (porro) - marked astigmatism
Eagle Optics Triumph 8x24 - marked astigmatism

My impression was that the difference in sagittal and tangential focus between the first two pair was slight, while the second two showed a rather "marked" difference. If the difference in focus could be measured, then a real comparison would be possible. This could be difficult since roof prisms generally focus by moving an internal lens.

Clear skies, Alan

 

[henry link]

Guy,

I apologize for sidetracking this thread away from your excellent comparison. I enjoyed your post very much. It's just what a prospective purchaser should try to do. I'll start a new thread to pursue the astigmatism vs. field curvature question.

Alan and Alexis,

I've been playing around a little today looking at an artificial star and a line chart at the edge of the field of a few binoculars. I'm beginning to doubt that astigmatism will be very easy to reliably quantify by eye, but field curvature could be easier (at least for one's own focus accomodation) by using reading glasses of different strengths. You just find the best edge focus without the glasses, then try glasses with different diopter corrections until you find one that duplicates the edge focus at the center. That should be the amount of field curvature in the binocular beyond your own ability to accomodate.

Henry

 

[Otto McDiesel]

Leica 10x42 Ultravid. Right away, in the store, it seemed that the Leica’s view was not as bright as that of the Zeiss or Swaro. The store’s dim lighting brought this out, as did viewing in deep forest and at dusk. In addition, the field of view was not as wide as the Zeiss or Swaro.

Actually, the field of view is identical. However, Leica do seem to have more distortion at the edge than Swaro, so you may have perceived this as a limited field of view, maybe.

 

[guyharrison]

Actually, the field of view is identical. However, Leica do seem to have more distortion at the edge than Swaro, so you may have perceived this as a limited field of view, maybe.

Otto,

I think you are right. After my post I did look at the specs again and I did notice that all three models had the same FOV (330'). This was a surprise given my very distinct impression of narrow view through the Leica. Then, I remember reading on these forums (and also some material from Leica) that they deliberately introduce some type of edge distortion, supposedly to make panning seem more natural, visually. I think this caused my impression of reduced field of view.

Having now used the Swaros without the edge distortion, I can say that I do not see any superiority at all in the Leica optical model when panning. I prefer the clean undistorted edges of the Swaro and the Zeiss.

I have just spend four full days of intense birding at the Merritt Island Nat'l Wildlife Refuge, Florida--an amazing destination. Species large and small, flightly and sedentary, in shade and in sun, in flight and stationary, near and far--over 60 SPECIES. My impressions on the 10x vs 8x are re-confirmed and emphasized--10x hands down! Although I did not have any models to compare, my choice absolutely delights me! (and probably one to order for my wife!)

Henry,

Thanks for your comments. I will read with interest your comments on field curvature vs. astigmatism--maybe this is what I saw at the edges of the Zeiss???

Guy Harrison

 

[Otto McDiesel]

Thanks for your comments. I will read with interest your comments on field curvature vs. astigmatism--maybe this is what I saw at the edges of the Zeiss???

Guy Harrison

Well, i did read all that techno-geek stuff about field curvature, and i did examine my 10x42 Ultravids again, and yesterday i managed to get a Swaro EL 10x42 (fast focus version) for two hours.

Well, my Ultravids do have very little more distortion than the EL. It is very little and not bothersome at all. And i was right, i can see better colors and contrast with the Ultravids than with the EL, but again, the difference is extremely small. In the end, it comes to handling and preference, really.