Vortex Diamondback HD 10x42 vs Viper HD 10x42

Field of view: Viper HD leads

Printed at 341 ft at 1,000 yd, the Viper HD 10x42 shows 6.5 degrees. The Diamondback prints 330 ft at 1,000 yd, which is 6.3 degrees. Both are the same 10x42 size, so the gap comes from the optical design.

Among the 87 models of this size in the records, the median field is 336 ft. Viper HD is number 29 and Diamondback HD is number 47, so one sits above the median and the other just below it. A field of view calculator turns these figures into a width at any distance.

Eye relief: Viper HD leads for glasses

Eye relief is 17 mm on the Viper and 15 mm on the Diamondback. The RSPB says eyeglass wearers should look for at least 16 mm, so only the Viper clears that mark.

The median for this size is 16 mm. Viper HD is above it and Diamondback HD is below it. Audubon says binoculars made for birders offer 15 to 20 mm, so the Diamondback sits at the bottom of that range. The eyeglass check tool and the binoculars for glasses wearers list cover this further.

Brightness at dusk: equal

Both are 10x42, so the exit pupil works out to 4.2 mm on each. Nikon defines exit pupil as the objective diameter divided by magnification, and says a larger one gives a brighter view in dim light.

Calculated twilight factor is 20.5 on both and calculated relative brightness is 17.6 on both. On these figures neither has an edge at dusk. Any difference would come from glass and coatings, and the records print no transmission figure for either. An exit pupil calculator shows the same sum for other sizes.

Weight and close focus: Diamondback HD leads

At 21.3 oz, the Diamondback is light for its size. Viper HD weighs 24.9 oz, which matches the median of 24.9 oz for this size.

Close focus favors the Diamondback too, at 5 ft against 6 ft. The median is 6.6 ft, so both focus closer than most 10x42 models. That helps with insects, flowers and anything else near your feet.

Build and fit: the same on paper

Each is printed as designed to withstand harsh weather conditions, and each is filled with argon for fog resistance. Celestron describes dry inert gas as a barrier against internal moisture. Tripod adapters fit both, and both focus with a center wheel.

Eye spacing runs 55 to 73 mm on the Diamondback and 55 to 74 mm on the Viper. Hunting is the maker named use for both. See the waterproof and fogproof guide for what these terms mean, and the binoculars for hunting list for more models.

Price band and who should pick which

Maker list price bands are $200 to $500 for Diamondback HD and $500 to $1,000 for Viper HD. Browse the $200 to $500 list or the $500 to $1,000 list to see other models at each level.

Pick the Viper if eye relief or the wider 341 ft view matters most. Go for the Diamondback if you carry binoculars for hours or look at close subjects at 5 ft. The wider 10x42 size page and best binoculars compared set both against the rest of the field.

Diamondback HD 10x42 or Viper HD 10x42

The Viper wins on view width and eye relief, and it is the one to choose if you wear glasses. On weight and close focus the Diamondback wins, with a lower maker list price band. Brightness at dusk is equal on the figures.