Originally Posted by Renze de Vries
I haven't seen the Leica HD yet, but my impression is that Leica just dropped in different glass without changing anything else, coating for instance. While I think that this is in itself a good it may not come as a surprise the improvements are minor.
In the Zeiss the use of FL glass was part of a more rigorous design change and so the improvements over previous and competitive models are quite notable.
The same goes for the Kowa XD, where FL glass and improved coating is applied to air-spaced objective lenses. If I'm correct, Kowa in their XD uses more FL glass than any other binocular on the market today. As with the Zeiss the results are excellent. Judged on CA and resolution alone my impression is that the Kowa probably even has the edge here. I for one wouldn't think of swapping my XD 8.5 for a Zeiss, not for a minute.
No, they changed more than that. You can't just drop in a different lens material and have everything work out. The mating element in the doublet also needs to be changed, as well as the optical design of the overall objective (radius of curvature on all three surfaces in the doublet, possibly the material and curvature of the third element in the objective, etc.).
The other changes Leica claims include:
- Modification to the design of the focuser to make it smoother
- Hydrophobic coating on the outer most surface of the objective
Some of the marketing literature implies that the formulation of the HDC (anti-reflective coatings) changed as well to improve transmission rates without distorting colors. However, I am unclear on whether this change was made with the HD line or with the introduction of the Ultravid series itself. I suspect the latter.
Personally, I do not find the changes in the HD line significant enough to justify the increased cost. The improvements in chromatic aberration are minor at best (I can't actually detect a difference); my Ultravids already had smooth (if underdamped) focusers, and since I use my binoculars for astronomy rather than hunting or birding, the hydrophobic coatings are of no use to me. I never was able to see much starlight during a rain shower!
You are certainly correct that this change is a "tweak" rather than a redesign. Consistent with that, Leica only changed the suffix of the model line rather than renaming it from "Ultravid" to something else. This seems appropriate to me.
It seems to me that Leica was simply making the minor changes required to ensure their high end binocular looks as good on a spec sheet as their competition's.
Personally, I don't get too excited about the inclusion of this ED glass type or that FL material. Without knowing the materials used as mating elements, the simple inclusion of Fluorite crystal or synthetic Fluorite glass tells you nothing about the level of color correction or resolution. Frankly, at the typical 8x power at which most binoculars are used, the resolution on virtually all well executed bins should be limited by the human eye, not by the objective lens. Much bigger issues in my mind are:
- Quality of construction
- Fit (ergonomics)
- Focus (ergonomics)
- Flatness of field (which determines sharpness in the periphery)
- Weight (ergonomics)
- Color accuracy
For me, the non-HD Ultravids represent the best combination of the above factors. The quality of construction is first rate, the fit (for me) happens to be quite good, though this will obviously vary from person to person, the focus is pleasant, but is perfectly accurate and functional, the flatness of field is very good (though there is still room for improvement), the weight is near the top of the class, the color accuracy is the best around, the brightness is a step below some of the competition, and the price is pretty good right now when compared to the HD version of the Ultravids.