How to Increase Sharpness With Depth of Field

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by

Pete DeMarco
in ,

Depth of Field (DoF) is an extremely important concept every photographer should know. Whether you want to blur the background in your photos or have everything in focus, it’s one of the keys to creating stunning images, and is often misunderstood by both beginner and more advanced photographers alike.

The Myth of F/8

If you’ve spent any time around photographers, especially landscape photographers, you’ve probably heard that f/8-f/11 is the holy grail of f-stops. It’s where most lenses are sharpest while offering a sufficient depth of field. That’s true.

Zhangjiajie, China, Hunan, photography, landscape, tips, dof, depth of field
For most of my landscape photos, like this one from Zhangjiajie in China’s Hunan Province, I set my aperture between f/8-f/11.

What is Depth of Field (DoF)?

You can still get sharp images with a deep depth of field using a low f-stop though. F/2.8 isn’t just for creating beautiful bokeh. Before I explain why, let’s get clear on a few important terms.

Depth of field (DoF) is defined as the distance between the nearest and the furthest objects giving a focused image. In other words, it’s a flexible zone that includes everything that’s in focus – from in front of to behind your subject.

For something more advanced, photographer Piet Van den Eynde (photo credit) explains how to create super shallow DoF panoramas using the Brenizer Method.

If everything is in focus from the front of your photo to the back, then you have a large depth of field. And if only your subject is in focus and everything in front of our behind it is blurry, then you have a shallow depth of field, like in the photo above.

Lower/faster f-stops (f/2.8 for instance) use larger/wider/open apertures that let in more light and produce a shallower depth of field. Higher/slower f-stops (f/22 for example) use smaller/narrow/closed apertures that let in less light and give a deep depth of field. Confusing, right?

3 Ways to Control Depth of Field

The mistake some photographers make is thinking the only way to control depth of field is to change the aperture. Actually, there are three ways you can control depth of field in camera: by aperture, focal distance, and focal length. Let’s take a look at each method and this great cheat sheet by Digital Camera World.

  1. Adjust your aperture. Use a low f-stop (f2.8) to get a low depth of field and a high f-stop (f/22) to get a high depth of field.
  2. Change your focus distance. The closer you are to the thing you are focusing on, the less depth of field you’ll have and vice versa. In other words, move further away from your focal point to increase your depth of field.
  3. Change the focal length of your lens. Wide lenses (like 16-35mm) give a wider depth of field. And telephoto lenses (such as 70-300mm) produce a narrower depth of field.

Sharp Photos at f/4: Changi’s Rain Vortex

What should you do if you’re shooting in low light and you don’t have a tripod? Or maybe you do have a tripod but you want to increase your shutter speed to freeze the movement in your scene.

Airport and jaw-dropping don’t go together, unless you’re at Singapore’s Changi. It’s home to the Rain Vortex, the world’s tallest indoor waterfall. I took this hand-held shot at f/4.

When I photographed the Rain Vortex at Singapore’s Jewel Changi Aiport, I had to use a low f-stop for two reasons. I wanted a faster shutter speed to freeze the motion of the water, train, and people. Also, I couldn’t use my tripod – it was too crowded where I took the photo – to shoot at a slow shutter speed.

This photo is from the same image above only cropped in. The bridge was my focus point.

As a result, I shot wide (16mm) and made sure I was far away from the thing I was focusing on (about 100m/328ft ). In this case, I focused on the bridge just in front of the rain vortex.

According to my PhotoPills app, if you shoot at 16mm on a full-frame camera and stand 100 meters (328 ft.) from your subject like I was, then the depth of field in front of your subject will be almost the same distance in front, and to infinity behind it.

If you took a string and stretched it out to the bridge I focused on, then dropped the end of the string to the floor a few stories below me, I bet it would be a similar distance. That means what was below me should be in focus as well because it was within my depth of field.

As you can see from this cropped in view of the above Rain Vortex photo, the foreground was in focus as well. It was within my depth of field at f/4.

Pro Tip: Keep it simple. I never check my depth of field with an app or calculate the hyperfocal distance. I just focus on whatever is one-third of the distance away from me into my scene.

Conclusion

Whether you’re a landscape, portrait or street photographer, understanding depth of field opens a world of creative possibilities. It’s true that f/8 – f/11 makes for a great starting point. In some situations though, you’ll need to move outside the box to nail your shot. Use aperture, focus distance, and focal length, to make your photo sharp by increasing your depth of field. Make it one of your photography goals to master DoF!

Do you have any questions about depth of field, aperture, or image sharpness? Just ask in the comments below.

Comments

4 responses to “How to Increase Sharpness With Depth of Field”

  1. Ian Dodd Avatar
    Ian Dodd

    Hi, I am interested in obtaining Max DOF in Macro Photography. Focus stacking seems to be the best method I have experienced. I use a 100mm macro lens in full manual mode. What f stop do you suggest for each in focus shot taken from front to back when the focus point is managed either with a rail or manually focusing each point with the lens focus ring. Here the camera is remaining at a fixed distance compared to using a rail. Your reply is appreciated.(I photograph Fungi in rainforest conditions where sometimes the light is filtered but generally shoot at ISO 100.) I seem to get best results with f11-f22 I don’
    t think the focus distance is long enough to use f4. Your reply is appreciated.

    Reply
    1. Pete DeMarco Avatar
      Pete DeMarco

      Hi Ian, I’m not a macro photographer, but I’ll try to help out. As I mentioned in the article, most lenses have a sweet spot where they perform best. It’s usually 2 or 3 stops from the widest f-stop of your lens. For instance, if your widest aperture on your lens in f/4, then your lens will most likely be sharpest at f/8 or f/11. So in your case, I’d stick with f/11. Also, you’re depth of field would be much lower at f/4, meaning you’d have to shoot and stack many more images than at f/11.

      Another thing, if you’re using a zoom lens, it can also be sharper at different focal lengths. My 16-35mm is said to be sharper at 16mm than 35mm, although I’ve never really checked. The best thing to do is to research the ideal focal length and f-stop of the lens you’re using. You can find that with a quick search on Google.

      Reply
  2. Tuan Anh Avatar
    Tuan Anh

    Hi Pete,
    Thanks for such a great informative post.
    One thing i’m not really clear of though, you mentioned near the end that you “just focus on whatever is one-third of the distance away from me into my scene”. What do you mean by “one third of the distance away to the scene”? Is it the bridge that you’re focusing on one third of the distance between you and the vortex? And why is the number 1/3?
    Thanks again and looking forward to your reply.

    Reply
    1. Pete DeMarco Avatar
      Pete DeMarco

      Hi Tuan Anh, I’m glad you found the article helpful. If you imagine the rule of thirds grid over your composition, then usually I’m focusing on the bottom third line. That usually works for landscapes and cityscapes. However, in this frame, the walking bridge (and the train bridge) were about one-third the distance away from me – in relation to the objects furthest from my camera, which would be the trees at the very back. And since my focus point (the person on the bridge) was very far away from me, then I get a greater depth of field too. I’m not sure if that makes sense. It’s much easier to explain with a video or images than in words.

      Reply

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