Pentax Papilio II 8.5x21 vs Pentax AD 8x25 WP
Quick take: The Pentax Papilio II 8.5x21 costs $30 less; the Pentax Papilio II 8.5x21 reaches farther (8.5x vs 8x); the Pentax Papilio II 8.5x21 has a wider field of view (315 vs 289 ft @ 1000 yds).
Field of view, to scale
Top-down view · drawn to true scale — no exaggeration
Which one to buy
Rain or bugs: Pentax built these two compacts to opposite briefs, and owners of each say as much. The Papilio II 8.5x21 focuses down to 1.6 ft, which no other binocular matches, and turns a beetle or a wildflower at arm's length into a frame-filling subject. The AD 8x25 WP focuses to 9.8 ft, but it is O-ring sealed and nitrogen filled, where the Papilio isn't waterproof at all. They weigh almost the same, 10.2 oz and 10.6 oz, and the AD costs $30 more.
Glasses tip things further toward the AD. Its 21mm of eye relief is rare in any compact, and owners call it the model's defining strength; the Papilio's 15mm is enough for glasses wearers to see the full field, reviewers say, but with less margin. The AD's phase-corrected roof prisms give a sharp, contrasty image by owner account, and its 3.1mm exit pupil is a little brighter than the Papilio's 2.5mm, which owners call the dimmest in that family.
The Papilio's optics are better than its trick suggests: owners report sharpness nearly to the edge and only a thin green fringe on harsh edges. It also has the wider field, 315 ft against the AD's 289 ft, which AD owners consistently call narrow. Its costs are hand shake at 8.5x, a small focus wheel that's hard to turn in gloves, and no objective covers.
For travel, hiking and weather, the AD is the more useful compact. The Papilio is the one to own when close-range nature is the whole point, and the one you keep out of the rain.
Pentax Papilio II 8.5x21
For gardeners, naturalists and anyone who wants to study insects and flowers at 1.6 ft in fair weather, for $30 less.
Pentax AD 8x25 WP
The better travel and hiking compact, especially for glasses wearers, and the one that shrugs off rain.
| Spec | Pentax Papilio II 8.5x21 | Pentax AD 8x25 WP |
|---|---|---|
| Approx. price | ~$149 | ~$179 |
| Use case | General Purpose | General Purpose |
| Magnification | 8.5x | 8x |
| Objective | 21mm | 25mm |
| Exit pupil | 2.5mm | 3.1mm |
| Field of view | 315 ft @ 1000 yds | 289 ft @ 1000 yds |
| Eye relief | 15mm | 21mm |
| Close focus | 1.6 ft | 9.8 ft |
| Prism | Porro | Roof |
| Glass | BaK-4 | BaK-4 |
| Coating | Fully Multi-Coated | Fully Multi-Coated |
| Weight | 10.2 oz | 10.6 oz |
| Dimensions | 4.6 x 4.3 in | 4.3 x 4.1 in |
| Warranty | 25-Year Limited | 25-Year Limited |
Feature comparison
Pentax Papilio II 8.5x21
- ✗ED Glass
- ✗Phase-Corrected
- ✗Dielectric Coating
- ✗Waterproof
- ✗Fogproof
- ✗Image Stabilized
- ✓Tripod Adaptable
- ✗Magnesium Body
- ✗Locking Diopter
Pentax AD 8x25 WP
- ✗ED Glass
- ✓Phase-Corrected
- ✗Dielectric Coating
- ✓Waterproof
- ✓Fogproof
- ✗Image Stabilized
- ✗Tripod Adaptable
- ✗Magnesium Body
- ✗Locking Diopter
What birders say
Pentax Papilio II 8.5x21
- ✓Same unmatched 1.6 ft close focus as the 6.5x, but with 8.5x magnification - small, slow insects fill dramatically more of the view at arm's length
- ✓Forum users specifically favor the 8.5x for slower and smaller subjects, where the extra power reveals detail the 6.5x can't
- ✓Expert testing found the image sharp from center nearly to the edge with only minimal softening
- ✓Chromatic aberration control rivals far costlier glass - just a very thin greenish fringe on the harshest high-contrast edges
- ✓Won a best-compact award from a major review site, which scored it 75% overall
- ✓Low-geared three-turn focus makes critical focusing at 20 inches genuinely precise - fine-tuning is a breeze
- ✓Twist-up eyecups with three firm click-stops and 15mm eye relief let eyeglass wearers see the full field without tunneling
- ✓Thoughtful extras: snug custom case, quick-attach strap system, and a built-in quarter-inch tripod thread
- ✗Tiny 2.5mm exit pupil is the dimmest in the Papilio family - image brightness drops off noticeably in dusk, heavy shade, or dim interiors
- ✗Narrower 315 ft field of view makes finding and tracking fast-moving butterflies harder than with the 6.5x - the forum consensus favors the 6.5x for quick subjects
- ✗8.5x magnification amplifies hand shake, both up close and at distance
- ✗Not waterproof or fogproof - reviewers say light rain is acceptable but rule it out for canoeing, kayaking, or wet climates
- ✗No objective lens covers included
- ✗Small 17mm focus wheel is difficult to operate in winter gloves
- ✗Diopter ring doesn't lock
- ✗The low-geared focus that helps at macro distances makes rapid refocusing on distant subjects slower
Pentax AD 8x25 WP
- ✓Extraordinary 21mm eye relief - nearly unheard of in a compact, letting eyeglass wearers see the entire field with ease
- ✓Phase-corrected BaK-4 roof prisms - a premium touch at this price that visibly improves contrast and color rendition
- ✓Genuinely sharp, crisp image from the fully multi-coated optics - reviewers say it feels solid and optically beyond its price
- ✓Truly waterproof: O-ring sealed and nitrogen-filled, unlike most budget compacts
- ✓Just 10.6 oz and pocketable - the binocular that actually comes along on hikes, travel, and events
- ✓Astronomy forum buyers celebrated finding it under $100 street price and reported the image quality was an outright bargain
- ✓Smooth focus wheel, solid hinges, and twist-up eyecups that reviewers say feel quality rather than cheap
- ✓Recommended by birding reviewers as a top entry-level and travel choice, holding its own against far bulkier mid-range models
- ✗289 ft (5.5 degree) field of view is narrow for the compact class - the most consistent criticism across reviews
- ✗3.1mm exit pupil dims noticeably at dawn, dusk, and in deep shade
- ✗25mm objectives simply can't match full-size binoculars once light drops - physics, not a flaw, but a real limit
- ✗Small, light body shows hand shake more than full-size binoculars - steady hands or a brace help
- ✗That narrow field makes initially finding birds in dense canopy harder, especially for beginners
- ✗9.8 ft close focus is unremarkable - no insect-watching double duty here
- ✗Priced above bare-bones compacts, so it depends on street-price deals to be a true bargain
- ✗No standout accessories - the case and strap are basic
Pentax Papilio II 8.5x21 vs Pentax AD 8x25 WP: common questions
Is the Pentax AD 8x25 WP or the Papilio II 8.5x21 better in the rain?▾
The AD 8x25 WP. It is O-ring sealed and nitrogen filled, so it is waterproof and fogproof. Papilio owners say light drizzle is about its limit, and reviewers rule it out for paddling or consistently wet climates.
Can the Pentax AD 8x25 WP focus close enough for butterflies like the Papilio II 8.5x21?▾
No. The AD's 9.8 ft close focus is unremarkable, and owners say it does no insect-watching double duty. The Papilio focuses to 1.6 ft, which is its whole reason to exist and something no other binocular matches.
Which Pentax compact suits eyeglass wearers better, the AD 8x25 WP or the Papilio II 8.5x21?▾
The AD 8x25 WP. Its 21mm of eye relief exceeds most full-size binoculars, and owners say glasses wearers see the entire field with ease. The Papilio's 15mm also works with glasses, reviewers found, but leaves less room for thick frames.