Get the right lens.
If you’re serious about getting sharp close-ups, investing in a DSLR and a telephoto zoom is the first order of business. If you’re shooting on a crop sensor, you can buy something like a 55-250mm for $300 or less, and if you’re shooting on a full frame camera and it’s in your budget, most manufacturers have 70-200mm and 70-300mm models that retail for anywhere from $600 to $2000 new. A 600mm telephoto lens is ideal for the pros, but that kind of glass costs over $10,000 -- and weighs as much as a cheetah cub, so it’s not ideal for the rest of us. Extenders, or teleconverters, are another option, but keep in mind these reduce the maximum aperture of the lens, making it harder to shoot in low light settings.