Opticron Adventurer II WP 10x42 binoculars

You'd be hard pressed to find a better pair of binoculars for the price

Binoculars that are light, compact and waterproof are ideal ‘take anywhere’ instruments, which is why we were so keen to try the Adventurer II WP 10x42s – an updated model in Opticron’s entry-level ‘Adventurer’ roof-prism range.

The binoculars are supplied in a soft, lightly padded case with a belt loop, a detachable shoulder strap and a microfibre cleaning cloth. The unpadded neck strap of the binoculars themselves is a comfortable 38mm wide. When you hold the binoculars up to the light, each of the exit pupils is perfectly circular, indicating that the prisms are adequately sized. We measured the exit pupil at 4.2mm, confirming that the binoculars are not stopped down internally to mask optical aberrations; this gives the Adventurer II a greater effective aperture, and hence potentially better light-gathering ability, than some binoculars that are nominally 10 50s.

The focus mechanism has a smooth, positive feel and in use we found that stars snapped to a crisp focus. The images from each side were perfectly merged, showing that collimation was spot on. When you refocus from a near object to a distant object, you will find that there is still three quarters of a turn of the focus wheel remaining. If you are shortsighted, you will be able to use this extra focal range to observe without corrective lenses. The eye relief (the ideal distance of your eye from the binocular lenses) is specified as 15mm but, even with the Adventurer II’s eye cups fully down, this was insufficient to allow the whole field of view to be visible with spectacles. This could make them unsuitable if you need spectacles to correct for astigmatism.

Distortions be gone

There was very mild pincushion distortion noticeable at the edge of the field of view. This makes straight lines appear to bow inwards, but also counteracts an unpleasant effect called ‘rolling ball’, which is present if there is no distortion.

Control of false colour was very good on axis, and even a gibbous Moon showed only minimal colour fringing when the limb or terminator was near the edge of the field of view. False colour on bright stars such as mag. 0.0 Vega in Lyra was barely perceptible. There was some lens flaring when the Moon was just beyond the field of view, and when

SKY SAYS… They are not stopped down internally, so have potentially better light-gathering than some nominal 10◊50s