The RF 28-70mm differs from its L-series counterpart (the RF 24-70mm f/2.8 L) by maintaining a much smaller and lighter form factor. It achieves this through an advanced optical design and a more conservative, yet still very capable, 28mm wide-angle starting point. When not in use, the lens can collapse into itself, resulting in even greater space savings in a bag or when slung over the shoulder.
The relatively fast constant maximum aperture of f/2.8 allows this lens to have significant advantages over similarly sized options that opt for a more conventional f/4 aperture, enabling the creation of images with a shallower depth of field. Portrait shooting and low-light shooting will benefit from the more pleasing bokeh and increased light-gathering capabilities, respectively.