“I am somewhat puzzled when I read about professional landscape photography where they use fast lenses such as f2.8 or f1.4. Why do they use these lenses when most landscape photos are taken anywhere from f8 to f22 and the supposed sweet spot is f11 (or close to it) to get good depth of field throughout.
Where does the f/2.8 come in for landscape photography?”
I recently received this question from CaptureLandscapes newsletter subscriber Kevin McArthur. It’s a great question and one I’ve seen pop up on various occasions. Do you need a lens with a wide maximum aperture? Do you need an aperture like f/2.8?
What is the Sweet Spot of the Lens?
The sweet spot of a lens is located two to three steps out from the widest aperture. For a lens with the widest aperture of f/4, that means the sweet spot is between f/8 and f/11. A faster lens with an aperture of f/2.8 will have its sweet spot between f/5.6 and f/8.
This range has the apertures which result in the overall sharpest images. As I talk about in our Introduction to Aperture in Landscape Photography, an aperture such as f/22 will have more of the image in focus but it won’t be as sharp as an aperture such as f/8.
A wide aperture such as f/2.8 or f/4 results in less of the image being in focus but the in-focus parts are sharper than what they would have been at a more narrow aperture.
Do You Need f/2.8 for Landscape Photography?
Even though the sweet spot is at f/11, it doesn’t mean that’s the best aperture for all images.
Yes, f/7.1-f/11 will result in the in-focus parts being at the sharpest (as Kevin said, a good depth of field throughout) but that’s not always what we’re looking for in an image.
For example, if you’re photographing in a foggy forest and there’s one tree that stands out, you can use a wide aperture such as f/2.8 to make the background/surroundings soft. Using a wide aperture is a great way to emphasize the focus on a specific object. Take this image as an example:
A wide aperture such as f/2.8 is also ideal for night photography. In fact, it’s a whole lot better than f/4 and you’ll see a big difference between them even though they’re both considered open apertures.
Should You Purchase f/2.8 or f/4?
Kevin also had a second question touching on the same topic:
The cost between a 16-35mm f/2.8  and a 16-35mm f/4 zoom is at least twice the price. If a landscape photo is taken on both those lenses at f/11 would you see the difference between the two?
Awnser: Not really since the sweet spot for the 16-35 f/2.8 is between f/5.6 and f/8, and for the 16-35 f/4, it’s between f/8 and f/11. Each lens should perform equally well at their optimal apertures (though I would have a look at the reviews of the lenses before purchasing.)
That being said, the benefit of the Canon 16-35mm f/2.8 is that it also is a great lens for night photography. Even though it’s a more expensive lens ($1,999 vs. $999 for the Canon 16-35mm f/4), you won’t need another to photograph the night sky.
Your choice, independent of budget, depends on what you will be photographing. If you enjoy night photography or plan on taking it up, I would recommend purchasing the f/2.8 as the wider aperture will make a big difference. If not, the f/4 is a reasonable option and it does save a considerable amount of money.
I love reading and replying to your questions so keep them coming by replying to one of our newsletters!
Great article Christian. In addition I will mention the weight of the lens. A f/2.8 lens is much heavier than a f/4.0 lens. Can make a difference when you’re travelling.
You’ve got a good point Christophe! The weight difference between a f/2.8 and f/4 is considerable and can especially make a huge difference for hikers and mountaineers.