Bindings are used to hold your ski boots rigidly to your skis. They are critical to your safety because they allow your foot to release when excessive force is applied to prevent injury. Most bindings are now step in. Simply put your toe in the front of the binding and push down on the heel to click in. Bindings are made up of five major components; AFD (anti-friction device), heel-piece, toe-piece, brakes and riser plates. The toe piece releases in the sideward direction and some release in the upward direction. SkiEnthusiast only recommends bindings with upward toe release because I have been in several situations (ski tip jams in the snow while body fell backward or foot got dragged under the lift) that would have resulted in leg injury if this release was not present. Heel-pieces release in the upward direction. The AFD is located beneath the toe of the boot and minimizes friction during a fall so the boot can easily slide out. Note there is a small gap between the sole of your boot and the AFD under normal use (ski boot will actually go down to make contact with it during a fall). AFD’s vary some with models and manufacturers ranging from a smooth pad to mechanical devices. The brakes on all bindings are practically the same and are used to stop the ski when attaching the boot or after it releases during a fall. The riser plate is used to lift your boot further off the ski to prevent it from scraping the snow when you are strongly riding your edges (picture a GS racer). Bindings also provide adjustable forward pressure (or lengthwise flexibility) to prevent the boot from jamming during a fall. The mechanical devices that accomplish this vary with model and manufacturer. Furthermore, some bindings provide vibration dampening, added rigidity and fore-aft adjustment (i.e. forwards and backwards). Fore-aft adjustment allows you to change your position on the ski without having to make new screw holes in the ski for binding attachment.
Din settings set the threshold of force for the binding to release. This standard has been agreed upon internationally and applies to all bindings. Beginners will have low Din settings and advanced and expert skiers will have higher settings to compensate for the more challenging terrain and higher speeds at which they ski. I have found no reliable site that publishes Din settings for free. It is best to obtain a copy from the boot manufacturer or order a copy from a Din specification reseller. However, it is recommended that you only have this done by a trained professional that can set and test that it is working properly.
When purchasing bindings, you will want to ensure that your binding works suitably with the skis you own or are about to purchase. In most cases this is not an issue, but I have seen a few exceptions. Also review the most recent technology from the manufacturers web sites before you buy and find one that best matches your preferences. Be sure to ask about warranties and money back guarantees because some manufacturers offer more when you purchase a ski and binding system together. For example SkiEnthusiast received a performance guarantee when a pair of skis and bindings were purchased together that I would not have received if I purchased a different set of bindings. This worked out in the end because I did not like the performance of the skis I purchased and was able to exchange them for another pair. SkiEnthusiast has had good performance from both Salomon and Marker bindings. I have provided binding manufacturers below for reference. Just google name as links usually change.
Atomic | Fischer | Look | Knee Binding | Marker | Rossignol | Salomon | Tyrolia