Vortex Kaibab 18x56 HD

With its extremely high power, the Vortex Kaibab 18x56 HD binocular is an ideal instrument choice for uses like long range hunting and general wildlife observation. As well as this, it could be useful for uses like security, border patrol, observing boats leaving the harbor or viewing ships at sea.

The 18x56 configuration is rather unique and well worth discussing as it offers up a number of benefits as well as drawbacks:

• Firstly the advantages of the high 18x magnification include improved image detail at much longer distances. The disadvantages of having such high magnifications are a much more unsteady image, a narrower field of view and potentially a less bright image and a diminished performance in low light conditions.
• Note, the unsteady image problem can be solved by mounting the binocular onto a tripod, which is exactly what Vortex recommends and is indeed how this Vortex Kaibab binocular is intended to be used as it is not only tripod adaptable but comes with a tripod adapter included.

Higher magnifications require thicker lenses, which can reduce the amount of light that passes through them. This can result in a less bright image being produced. However, because Vortex Optics has used extremely high-quality glass and optical coatings like the special anti-reflection coatings on all lens surfaces, as well as the very best dielectric mirror coatings on the prisms, this problem is also solved as the light transmission levels are excellent.

However, In low light, these binoculars are not an ideal choice. We can see that by the fact that the 18x56 configuration produces a small 3.1mm exit pupil. This is adequate for daytime use, but in low light when the pupils in your eyes dilate to a size larger than the exit-pupil it means that these binoculars are not supplying your eyes with enough light for you to make a bright image.

If you require a good low light performance, a binocular like the Vortex Razor HD 10x50 with its 5mm exit pupil will be a better option.

The use of an APO lens system is another very important highlight on this Vortex Kaibab binocular. This system uses three instead of the normal two lens elements in the objectives. This along with the fact that they also use extra-low dispersion glass results in very high-definition images with excellent resolution and color fidelity.

These Vortex Kaibab 18x56 HD binoculars have a field of view that is 64 meters wide at 1000 meters, which is quite narrow when compared an average 10x binocular and is one of the downsides to a high magnification.

The comparatively long close focus distance on the Vortex Kaibab means they are not a good choice for close-up observations but as they are designed for long range uses, this should not be a factor for most users.

These Vortex Kaibab binoculars have twist-up eyecups. This combined with 16.4 mm of eye-relief is perfectly adequate and should be enough even if you wear glasses.