What is a “fast lens”?

“Fast lens”, “fast glass”. What does that mean?

People often refer to camera lenses as “glass” because lenses are made of glass.

A fast lens is a name for a lens with a large maximum aperture. Lenses that come with a maximum aperture of like f/1.2, f/1.4, f/1.8, f/2.0, or f/2.8 are considered as a fast lens.

What does aperture have to do with being “fast”?

Large aperture means the lens opens up wide to let in more light to the camera sensor which allows you to use faster shutter speed.

Let’s say I’m using a not so fast lens with a maximum aperture of f4.0. I’m photographing in a lighting condition where my camera setting needs to be at ISO 2000, shutter speed 1/40 and my aperture at its widest f/4.0. At a slow shutter speed 1/40, I’m concerned about getting a lot of shaky photos due to movement or motion blur.

If I were to use a “fast lens” at aperture f/2.0 under the same lighting conditions, I’d be able to raise the shutter speed to 1/160 and get the same exposure without having to worry too much about motion blur.

Learn more about APERTURE

Learn more about ISO

Learn more about SHUTTER SPEED

Here are some fast lenses that I’d recommend for Canon or Nikon DSLR cameras.

About papixelhub

Hi there, I’m Prem Amrit ! I’m an entrepreneur and digital marketing consultant from Patna, India. I founded my own digital agency, where I help SMBs leverage social media, SEO, and content marketing to grow their traffic and generate qualified leads for their business. I started Papixelhub in 2019 as a side project to document all the strategies, tools, and tactics that I was using to grow my small agency. The goal was simple: to arm other solopreneurs with all the right information they needed to launch a successful business.