How to find the top rated binoculars?

Well bigger isn't always better, sometimes it's just bigger. top rated Binoculars have specs that you can read off the box that will somewhat tell you if it's good or not, but unfortunately the quality of optics is something that can't be rated. The few things you can tell from reading the specs are:

Type, porro vs roof. Under $150 go for porro, over $150 then you can start looking at roofs. Roofs are sleeker, they have parallel tubes, while porros are wider, with the objective lens at an offset from the occular. Porros are cheaper to make, so at the lower price ranges they will have better glass quality than roofs

Prism, BAK4 or BK-7. BAK4 are better prisms than BK-7.

Lens coating, Fully Multi Coated > Multi Coated > Fully Coated.

For roofs, look for models with phase correction. On roof binos, the incoming light is split and then remerged, phase correction makes the incoming light remerge at the same time, giving you crisper images, without it a roof bino will have blurry edges.

Things you can't find out without trying the bino include:

Lens quality, even when all of those things above are the same, two binos can still differ greatly on the final outcome, a bushnell excursion a $150 bino with all of the best features from above can't hold a candle to a swarovski, a $1500 bino.

Eye piece design, when you look through a cheap $40 bino, it will seem like you're looking through...well tubes. Look through a pair of $400 bino and all you see is the image, you don't feel like you're looking through a tube.

Also, when buying binos, it also helps to know what he's using it for. A birding bino is different than one for astronomy for instance. In almost all uses, you want to keep that power below 10, anything above Drugs Without Prescription 10, regardless of how steady you are you will see the image shaking.

Bigger objective lens means more light will come in, this is the number after the X, in this case his bino has 50mm lenses. It doesn't indicate field of view, a wide angle 50mm lens will have wider FOV than a regular 50mm. The bigger the lens means also that the bino is less compact, a 50mm bino won't fit in your pocket. Brightness also has to do with the quality and type of coating. Fully Multi Coated (FMC) lenses will transmit the most light, as opposed to a Multi Coated (MC). A 26mm FMC lens, will transmit more light than a 50mm Fully Coated (FC) lens. The image on my $200 26mm bino is brighter than my $30 50mm bino.