Daisy Flowers
These daisy flowers have been taken with a macro lens to enable me to get close enough to fill the frame.
To get good composition in your images it is good to get in close and fill the frame.
There are many different macro lenses available and some of them for Canon and Nikon cameras are summarised here on this site.
Generally macro lenses range in focal length from around 40mm and go up to 200mm. The longer lenses being useful for critters which may be easily frightened.
Cormorant
This cormorant has been captured with a Nikon D700 camera and 300mm lens. The image has been converted to monochrome in Photoshop. Long lenses are required when approaching birds and you need to be careful not to disturb the bird. Some examples of the lenses required are discussed in the following links.
It does not really matter what brand of camera you are using as they are pretty much the same when comparing cameras at similar price points, but the lens is very important. Use a lens with as low an aperture as you can afford.