Sightron SIII Magnesium 8x32mm Binocular

By Randy Wakeman

Sightron SIII Magnesium 8x32mm Binocular
Photo by Randy Wakeman.

The Sightron SIII Magnesium 8x32mm roof prism binocular is lightweight, compact, rubber armored and waterproof. It is also, as the Sightron "SIII" designation has come to represent, a very high quality and high performance optic.


  • Model: SIIIMS832
  • Type: Compact roof prism binocular
  • Item Number: 25152
  • Sku Number: 793139-251527
  • Magnification: 8x
  • Lens Coatings: Fully multi-coated with phase coated prisms
  • Object Diameter: 32mm
  • Field of View: 394 ft at 1000 Yards
  • Exit Pupil: 4mm
  • Eye Relief: 15.3mm
  • Finish: Black Rubber
  • Waterproof: Yes
  • Weight: 19.7 ounces
  • Length: 4.5 inches
  • Warranty: Lifetime
  • 2014 MSRP: $596.97

At about 1-1/4 pounds and only 4-1/2 inches long, this upscale binocular is going to have wide appeal for general use by hunters and outdoorsmen. Compact and lightweight, it will save both weight and bulk on your next hunt. Compared to Sightron's excellent SIII LR 8x42 binocular, the SIII Magnesium 8x32 reduces the overall length by a full two inches and loses almost 3/4 pound in weight.

My latest visit to the optometrist was just a few days ago. My aging eyes dilate to 4.5mm within ten seconds in dim light, both eyes dilating an equal amount. According to my optometrist, 5mm is about the maximum mature adult dilation, but most human pupils close-up slightly after acclimation to dim light. In real-world terms, as an approximation, you'll probably be able to benefit from a 5mm exit pupil when your eyes are fully dark adapted (which takes about 45 minutes) and anything less than that is going to appear dimmer.

However, a 4mm exit pupil will be sufficient in dim light conditions, such as the hunting half hour before dawn and after sunset. By the time your eyes are fully dark adapted it will be too late to shoot, anyway. Naturally, your eyes will be different, something you might want to take into consideration for both binocular and riflescope selection.

The large center focus knob of this SIII Sightron is easy and precise to adjust and the binocular fits my hands well. The extendable, rubber coated eyecups are convenient. The diopter adjustment ring for the right eyepiece works as advertised.

After carrying this binocular in the field for the past couple of weeks, I found the fully multi-coated optics free from flare (NEVER look directly at the sun with any optical instrument) and free from any noticeable chromatic aberration or color fringing. The roof prisms are phase coated. It is easy to look through the SIII for extended viewing sessions.

This has been mentioned before, but if we look through binoculars for hours and a spotting scope for a few minutes, we probably look through a riflescope in a hunting situation for only seconds. Yet, often we obsess over optical trivia in riflescopes, but routinely ignore binoculars. This Sightron SIII is an outstanding choice for general purpose hunting and outdoor use.

That said, binoculars are more of a personal preference item than many other products, for they need to fit your hands and your face. If they do and you are looking for a high performance binocular that won't consume much real estate, the Sightron SIII 8x32mm is an excellent choice.

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Copyright 2014 by Randy Wakeman. All rights reserved.