When it comes to zoom lenses, the professional standard is f/2.8, which offers a suitably wide aperture for isolating subjects and working in low-light situations. However, many f/2.8 zooms also have f/4 variants, which are both far cheaper and much more portable. This great video essay discusses why you might want to consider f/4 options for your camera bag.
[ Read More ](Originally posted by Alex Cooke)