The Papilio 6.5 x 21mm close focuses to a mere 26 inches or less. Pentax specs it at 26”, but we typically measure it focusing as close as 20”. We can’t guarantee this latter measurement for your eyesight, however, so we’ll stick to quoting Pentax’s more conservative 26” close focus in our specifications. The Pentax Convergent Lens Optical System Engineering (CLOSE) mechanism automatically slides the left and right objective lenses toward the center as you focus at shorter and shorter distances. This special converging lens system keeps you from getting eyestrain or a headache when trying to focus very close.
At a 26” close focus, using the 6.5 x 21mm Papilio is the same as getting your eye within 4” of the butterfly or bug, with a field of view 3.4” across. Identifications are a snap.
The optics are fully multicoated to eliminate harmful ultraviolet rays while improving light transmission. This gives you high contrast images with no glare or flare. The Papilio uses high quality BaK-4 prisms to transmit more light at the edges of the field. This enhances the illumination for easier viewing in dim light. The body is a reverse porro prism design, in which the objective lenses are closer together than the eyepieces. This allows for nearly full-size binocular performance from a very compact body. A soft touch dark grey rubber armor with molded-in thumb grooves covers the durable and lightweight molded polycarbonate body to protect the internal mechanisms and provide a sure grip.
An eighth of a turn of the twist-up rubber-rimmed eyecups retracts them into the binocular body for eyeglass or sunglass use, rather than rolling down. This eliminates the possibility of the eyecups drying out and cracking with age and use, as with conventional rolldown eyecups. An eighth turn in the opposite direction extends the eyecups for non-eyeglass use. Eye relief is specified at 15mm. While this is technically correct, the actual usable eye relief typically measures a mm or two less due to the recessing of the eyepieces when the eyecups are in the down position for eyeglass use. A shorter eye relief than specified is typical of all binoculars. There will be some vignetting of the field for eyeglass wearers. The diopter adjustment on the right eyepiece is a click-stop design that won’t accidentally get out of adjustment when you least want it to. Focusing is somewhat slow, at three turns from close focus to the horizon, but extremely precise for close-in focusing.
For extended hands-free viewing from a fixed position, you can mount the Papilio on a camera tripod using an optional tripod adapter and the standard 1/4”-20 thread tripod socket located underneath the binocular body. The supplied soft case has a belt loop for no-hands carrying. The woven neckstrap is 3/4” across, not exceptionally wide, but more than comfortable for all-day use with the lightweight (10.2 oz.) Papilio. An eyepiece rainguard completes the supplied accessories.
Aside from its manifest virtues as a butterfly binocular, the Papilio is a handy bino for nature walks, hiking, traveling, spectator sports, the theatre, etc. – anywhere compact size, good optics, and light weight are important.