Long distance is the request that most often leads people to buy the wrong pair, because the obvious answer, more magnification, runs into two limits that no amount of money removes: your own hands and the atmosphere.
The handheld ceiling
Above about ten times magnification, the shake from your own pulse and breathing enlarges faster than the detail does. A steady 10x view shows more than a wobbling 20x one, which is why every serious long distance user either braces against something or mounts the binoculars.
The atmosphere, which decides more than the optics
Over long distances, heat shimmer sets the limit. On a warm afternoon across open ground the image boils above about 15x regardless of the instrument, and the same view at dawn can be sharp at 40x. Nothing in the specification changes this, and it is why experienced users watch conditions rather than buying more magnification.
What actually helps
Aperture, for brightness at dusk and dawn when conditions are best; image stabilisation, which genuinely works and lets a 12x or 14x pair be used handheld; and a tripod, which is cheaper than stabilisation and more effective. In that order, by cost effectiveness.
Questions people ask about binoculars
What are the best binoculars for long distance?
A 10x50 handheld, or 15x70 and up on a tripod. Beyond that a spotting scope is the right instrument rather than binoculars.
Are image stabilised binoculars worth it?
They work and they are expensive. A stabilised 12x pair genuinely delivers what an unstabilised 12x pair promises, which for handheld long distance use is the single largest improvement available.
What is high power binoculars?
Usually anything above about 12x. It is also where handheld use stops being practical, so the phrase should be read as a signal that you will need a mount.