Binoculars are the optics of choice when depth of field, colour, contrast and portability are the prime concern. Binoculars lens sizes and magnification factors are implicit in their product descriptions: an 8x32 binocular offers 8x magnification with a 32mm diameter lens. A 10x44 binocular offers 10x magnification with a 44mm lens diameter. One might think that getting a set of binoculars with the highest magnification factor would always be the best choice, but this is not necessarily so. Higher magnification means a smaller field of view, and conversely, lower magnification offers a wider field of view. When birding, as one must locate subjects with the naked eye, and then pinpoint their location with binoculars. Having a small field of view can make locating targets difficult once viewing through binoculars, so 8x magnification is most useful.
When hunting, being able to spot small detail at a distance is paramount, so greater magnification (10x magnification) is usually the preferred option. Larger lens diameters will allow more light to enter the optic, making for better low light performance, or for viewing objects in shadow, however larger lens diameters also mean larger, so selecting the correct pair is a function of the required magnification, light conditions, and size that you’d like to carry with you.