Pentax AD 9x28 WP specs and field of view
Eye relief of 18 mm marks the AD 9x28 WP as friendly to glasses, and it comes in a waterproof roof prism body at 12.9 oz. The field is 294 ft (at 1,000 yd) at 9x.
- Field of view
- 294 ftat 1,000 yd
- Eye relief
- 18 mm
- Close focus
- 9.8 ft
- Weight
- 12.9 oz
- Exit pupil
- 3.1 mmcalculated
Why pick it
- 18 mm eye relief, enough for glasses
- Waterproof
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Who the AD 9x28 WP suits
With 18 mm of eye relief, eyeglass wearers can keep the full view. The exit pupil works out to 3.1 mm, which suits daylight use, and the 1 m waterproof rating suits wet weather.
Close focus is 9.8 ft, so nearby subjects are out of reach, and the 294 ft (at 1,000 yd) field is narrower than the 351 ft of the AD 9x32 WP.
AD 9x28 WP is one choice among many, and the top binoculars compared covers the most popular ones. Pentax lists it in the $200 to $500 price band, alongside the models in best binoculars under $500.
AD 9x28 WP specifications
AD 9x28 WP figures as Pentax prints them; rows marked * are calculated from the 9x28 size.
| Magnification | 9x |
|---|---|
| Objective lens | 28 mm |
| Prism type | Roof |
| Field of view | 294 ft at 1,000 yd (98 m at 1,000 m) |
| Angular field of view | 5.6° |
| Apparent field of view | 48° |
| Eye relief | 18 mm |
| Close focus | 9.8 ft (3 m) |
| Eye spacing range | 56 to 72 mm |
| Weight | 12.9 oz (365 g) |
| Length | 4.6 in (117 mm) |
| Width | 4.5 in (114 mm) |
| Waterproofing | 1 m depth (JIS Class 6) |
| Fog-proofing gas | Nitrogen |
| Focus system | Center focus |
| Maker list price | $200 to $500 |
| Exit pupil | 3.1 mm * |
| Twilight factor | 15.9 * |
| Relative brightness | 9.7 * |
* Calculated from the size, not printed by the maker.
Other sizes of the AD
Pentax makes the AD in 2 sizes; a larger front lens adds brightness and weight, and more magnification narrows the view.
| Model | Size | Field of view | Eye relief | Close focus | Weight | Exit pupil | Amazon |
|---|---|---|---|---|---|---|---|
| Pentax AD 9x28 WP | 9x28 | 294 ft | 18 mm | 9.8 ft | 12.9 oz | 3.1 mm | Check price on Amazon |
| Pentax AD 9x32 WP | 9x32 | 351 ft | 16 mm | 8.2 ft | 17.6 oz | 3.6 mm |
Pentax binoculars
AD 9x28 WP questions
AD 9x28 WP: does it work with glasses?
AD 9x28 WP has 18 mm of eye relief, which meets the 16 mm the RSPB advises for people who wear glasses.
AD 9x28 WP: what does 9x28 mean?
AD 9x28 WP magnifies 9 times through 28 mm front lenses, which works out to an exit pupil of 3.1 mm, the width of the beam of light that reaches each eye.