APERTURE & F-STOPS

to explain exactly how optical physics will yield a greater plane of focus, just go ahead and blindly follow this tidbit of info. Just like a shallow depth of field (and the resulting blur) will vary based on things like the distance you are from the subject you’re photographing, the same is true of getting everything in focus.

Landscape photography is the most common time to use a very wide depth of field, getting as much of the scene in focus as possible. Rules are always meant to be broken, so not every landscape shot needs to be at a big f-stop number (f/8 and above), but many indeed are.

The above shot of the rim on Bryce Canyon is a great example of needing to use a wide depth of field to make sure everything is in focus. The orange soil and the white soil are actually separated by a small gap of around 50 yards as the canyon rim curves around from left to right. As a result, a shallow depth of field would have caused part of the scene to be out of focus. The white cliff would be out of focus if I focused on the orange, and vice versa. However, with a high f-stop, both are in focus in the above photo as desired.

One rule of thumb for landscape photography is to try and find something in the foreground to focus on. Check out our composition and landscape photography pages for more info on this. But foreground focus can pose challenges when it comes to wide depth of field. Because of the ratio of your camera to the subject (i.e., the foreground element) and from subject to the background, it’s imperative that you use a very, very large f-stop number. F/11, f/16 and even greater are often needed. Even in the above photo you can see how the Manzanita bush is in sharp focus, with the clay hoodoos in the background a bit out of focus.

TAKEAWAY

A large f-stop number will make more of the photo in focus.

Aperture is truly at the heart of photography, so having an understanding of it is critical for advancing the way you shoot. Inherently it is a rather simple process. Changing the aperture is a sliding scale and affects two things – the depth of field and the amount of light let in. However, the ramifications these two things have on your photos are paramount.

When it comes to understanding these ramifications, practice makes perfect. Get outside or on a nature trip and play around. The more shots you take, the better you’ll understand how to use apertures and f-stops to dramatically improve your technique and ultimately the quality of your photos.

Recap

• Changing the f-stop or aperture widens or narrows an opening inside your lens that lets light reach the sensor.

• A wide depth of field (more parts of the photo in focus) is achieved by having a narrow aperture (smaller opening), corresponding to a big f-stop (f/8 and above).

• A narrow depth of field will intentionally blur parts of the photo and is achieved by having a wide aperture (larger opening), corresponding to a small f-stop number (f/4 and below).

• F-stop numbers are all relative depending on the distance you are from the things you’re photographing and the proportion of the subject to the overall frame of the shot.

• Practice is critical to properly understand the effects of changing your aperture/f-stop.