Compacts are great for hiking or for a second pair to throw in your glove compartment, but I don’t find them very useful for general field use. The small objective lens limits both the field of view and the brightness of the image. Other factors to consider are the close focus (how near you can focus to see birds and butterflies 6 to 8 feet away), waterproof capability (for birding in the rain, in the tropics, or in a kayak), and eye relief (important for eyeglass wearers to be able to have the full field of view of the binoculars). Binoculars vary greatly and these factors, as well as how they feel to you, are important.
Binoculars come in all price ranges, from $25 to $2,500. It is best to try them out before you buy them, not only to match the binoculars to your needs, but also to get the one that feels good to you ergonomically, while staying within your budget. Binoculars are versatile for other uses, such as at sporting events, concerts, and while boating.
If you want to see more detail on distant objects, such as a snowy owl in the marsh, or an eagle perched across the river, you may need to invest in a spotting scope. While binoculars magnify 8 or 10 times and will allow you to spot a distant bird, a spotting scope will bring birds 15 to 60 times closer — important for seeing color and detail at far distances.
Such high magnification is impossible to hold steady without the use of a tripod, so scopes are much less portable. But they are necessary for long distance viewing, and they are great to take photos, with using a camera or smart phone, as well. Like binoculars, with scopes you get what you pay for. You can get a decent spotting scope for $300 to $400, or you can pay as much as $3,000 to $4,000. Again you’ll want to look through different makes and models to see which works best for you.