Being an incurable birdbrain (and I take that as a compliment), I cherish memorable birding experiences like my first views of the spectacular Great Gray Owl. I remember it well, standing near the Canadian border on a VERY cold February evening near dusk. Knee deep in snow with a bitter wind chill, I remember bringing my binoculars up to my eyes and trying to focus. In the bitter cold, the focus knob was so stiff I had to remove my gloves to turn the wheel with four fingers.
It's moments like these that make me thankful for the (near) lubricant-free focusing system used on Leica's Ultravid binocular lines (Ultravid BR, Ultravid BL, and the new Ultravid HD). Without excessive lubricants to congeal or run, the Ultravid focus knob offers a consistent feel regardless of external temperatures (e.g. doesn't stiffen in cold temperatures, nor does it become overly fluid on hot days). This also means no more frozen fingers!
The focus system on the Leica Ultravid line consists of a threaded brass collar which travels on an aluminum helicoid to drive the internal focusing lens. Since these two metals do not bind, additional lubrication is not necessary. The system offers the ideal amount of resistance to eliminate "over travel" when focusing fast, while insuring the focus wheel will not move until you want to move it.
In addition to consistent performance under all atmospheric conditions, the lack of lubricants in the focusing system also complements the outstanding longevity of the Ultravid binocular design. Over the course of your lifetime with this product, any dirt or dust particles that may find their way into the focusing system will not get trapped in grease and create sludge. As a result, the focus wheel performs spinningly–whether fresh out of the box or even decades later. It's no coincidence that so many people still use 30 year old Leica binoculars (formerly "Leitz") in the field today. They're manufactured with precision to last from day one!
Review contributed by Jeff Bouton, Leica Sport Optics.