Nikon Prostaff P3 vs Prostaff P7 in 8x42

Field of view: equal on paper

Both models print a 377 ft field at 1,000 yd, which is 7.2 degrees. Neither leads here. The two sit just apart in their size group: the P3 holds place 48 of 75 models of that size with a field figure, and the P7 holds place 49.

The median field for 8x42 binoculars is 393 ft, so both pairs show a slightly narrower view than the middle of the group. If a wide scene matters most, the field of view tool shows what 377 ft means at your distance.

Brightness at dusk: a tie

Both pairs have a calculated exit pupil of 5.3 mm, a twilight factor of 18.3 and a relative brightness of 27.6. Nikon defines exit pupil as the effective objective diameter divided by magnification, and says a larger exit pupil gives a brighter view in dim light.

Since the size and these calculated figures match, the two are level on paper. The figures do not describe coating quality, and the makers' documents list no coating details for either model, so glass differences stay unstated here. Use the exit pupil tool to compare other sizes against 5.3 mm.

Eye relief and glasses: equal

Both models print 20.2 mm of eye relief. The RSPB says eyeglass wearers should look for at least 16 mm, and both clear that figure. Both also sit above the group median of 18 mm for the size.

Audubon puts birder-friendly eye relief at 15 to 20 mm, so 20.2 mm is at the top of that span. Either pair suits glasses; the binoculars for glasses wearers list shows other models with long eye relief.

Weight and handling: the P3 is lighter

The P3 weighs 20.3 oz and the P7 weighs 20.8 oz. The P3 leads on weight, though both sit well under the size median of 24.2 oz. On a long walk, both pairs carry lighter than the typical 8x42.

Close focus is the same at 9.8 ft, against a size median of 6.6 ft, so neither suits butterflies or insects at short range. Both use center focus and a roof prism, and both list an eye spacing range of 56 to 72 mm.

Weather sealing: equal

Both are listed as waterproof to 1 m (3.3 ft) for 10 minutes with O-ring seals, and both are nitrogen filled. Celestron describes nitrogen filling as an extra barrier against internal moisture, which is the fogproof part.

Nikon states its waterproof binoculars should not be used underwater, so the rating covers rain and splashes, not swimming. See the waterproof and fogproof binoculars guide for how the terms differ.

Series and price band

The P3 carries a maker list price band of $100 to $200, and the P7 sits in $200 to $500. That is the clearest gap between them. The P3 series also comes in 10x42, plus 8x30 and 10x30. The P7 series adds 10x50 and 12x50 to those.

If you want to see both bands side by side, open binoculars at $100 to $200 and binoculars at $200 to $500. The wider P7 range also gives you a path to larger sizes in the same line.

Prostaff P3 8x42 or Prostaff P7 8x42

On the printed figures the two are the same binocular: 377 ft field, 20.2 mm eye relief, 9.8 ft close focus, 5.3 mm calculated exit pupil. The P3 is lighter at 20.3 oz and sits in the lower price band. The P7 adds a longer size lineup. See Nikon binoculars or best binoculars compared for more options.