I‘m a big believer in depth of field, also known as DoF. It’s a great way to give your photos a professional, artistic atheistic. It also had a practical function that it helps set your subjects off of the background by making them the main focus, (pun totally intended), of the picture.
Larger apertures, such as 1.4 and 2.8 are masters of soft fuzzy background, and a lot of photographers will only shoot portraits with their apertures wide open, even in well lit environment. I don’t have a problem with this, as I use my 2.8 lenses all of the time, but I think photographers will often forgo an equally good, (or even better in many situations), option of shooting with a f/4 lens.
Why Shoot With an f/4 Lens
There’s more than one reason why f/4 is just as good or better than f/2.8 or 1.4. First is the simplest reason: f/4 is cheaper. You can buy a canon 70-200mm f/4 lens for $1,300 or less, whereas the f/2.8 version of that lens is over $1,000 more expensive. Right off the bat you can save yourself a grand and spend that money on other things, such as a speedlight or maybe even a f/1.4 50mm for those times you feel like you an extremely shallow DoF.
The second reason is the lenses are just as good as their more expensive counter parts. I’ve been using my 70-200mm for over 8 years and the images it produces are spectacular. A larger DoF doesn’t mean better image quality, it just means softer backgrounds and better use of available light.
But wait! The third reason negates that whole, “larger aperture means more light,” argument all together. If you have a modern digital camera, say one that’s been released within the last 3 years, then you are reaping the benefits of decades of research and development spend on camera sensors.
My 5D Mark III can shoot at 6400 ISO with out any noticeable noise. I’ve shot at higher ISOs as well, and just a little post processing in Lightroom will remove what little noticeable noise there might be. Even my 5D Mark II, now 7 years old, can still handle an ISO of 6400 without an issue when using my f/4.0 lens with the help of a little noise reduction in post.
The last reason f/4 is great is because it has nearly the same DoF blur as a f/2.8 lens. And, in my opinion, I like the way DoF is handled at f/4 better. At 2.8 you’ll often notice that your background is turned to soup with shapes lost completely and colors bleeding together, muddying up what’s behind your subject. With f/4.0 you can keep a little of that color and shape separation in the background while still being soft and pleasing. Yeah, the difference is noticeable, but barely.
One more bonus with f/4 — sharpness. The smaller the aperture, the more over all focus you gain and when you’re taking pictures of people, animals or anything else that has a tendency to move. This extra focal depth could make the difference between landing the shot, and just missing it.
Illustrated below is just how similar f/4 and 2.8 really are.
So, don’t knock 4/f, embrace it!
Benjamin Lehman is a Commercial Wedding, Portrait and Advertising Photographer in the Canton, Northeast Ohio are.