IN COLLABORATION with my professional guest, Donna Crous

After we talked about Shutter Speed in the previous episode of this educational post series 'Let's Talk About...', it is time to learn more about the next important element of the exposure triangle, so today we will dig deep into our camera's aperture settings.

What is Aperture?

Aperture is a hole with a specified diameter within the lens. The light enters the camera body through this hole to reach the camera sensor. The larger the aperture (hole), the more light reaches the sensor, which also means the brighter the exposure will be.

It is like the Iris in our eyes, that we can control.

Aperture also controls the depth of field (DOF).  The best way to imagine it as a 'slice' of a scene, which is in razor-sharp focus. If the aperture is very small, the depth of field is large, while if the aperture is large, the depth of field is small. In practice, the larger the aperture is the more noticeable the difference will be between the 'slice' of the scene in-focus and out-of-focus. A small aperture will bring all the foreground and background into focus.

Aperture is typically expressed in f-numbers, f-stops, or focal ratio. The f-number is the ratio of the diameter of the lens aperture to the focal length of the lens and is also a way of describing how open or closed the aperture is.

Each f value halves the amount of light that reaches the sensor, which means, to keep the same exposure level, you will need half as fast shutter speed (using the same ISO).

For example:

Starting exposure: f/1.4 aperture + 1/1000s shutter speed (ISO100),

and the equivalent exposure at f/2 will require 1/500s (ISO100).

Red Wine Poached Pears - Photo by © Reka Csulak

Red Wine Poached Pears - Photo by © Reka Csulak

Exposure Triangle

In this blog post, we will focus on the aperture's relation to the other two settings, but we will look into aperture and ISO in the future for sure.

Find a detailed explanation of the Exposure Triangle here.

Large and Small Apertures

Aperture is really a stylistic choice, so you can vary it according to how you wish to control your viewer's focus when having a look at your photo.

You have the following options and the results of these settings listed below:

  • Large aperture - small f-numbers (f/1.8) - narrow DOF - blurry background (bokeh = adaptation from a Japanese word meaning blur)
  • Medium aperture - medium-range f-numbers (f/6.3 - 8) - medium DOF - still a bit blurry, but much detailed background compared to large aperture
  • Small aperture - large f-numbers (f/22) - wide DOF - detailed background


I recommend you doing a hands-on experiment! Let’s capture a very simple scene with two apples, place one at the front of your backdrop and the other one a little bit behind it.

Focus on the stem of the apple at the front. Simply use daylight. First, start with a large aperture such as f/1.8, then increase it to f/22.

  • Use a large aperture (small f numbers), and the apple behind will appear blurry while the apple at the front will be detailed with the area around the stem in focus. This setting is great to draw your attention to a hero subject while you still have a good sense of the surrounding objects' color and shape, but not their texture. This is a very popular choice of food and lifestyle bloggers.
  • Use a small aperture (large f numbers), and the apple behind will appear pretty much as sharp as the one at the front. This setting is great to show all elements on the photo razor-sharp, while you see not only the surrounding objects' color and shape but their texture as well. This is a common choice in product photography when a dish and the product label in the background have to be as detailed as possible.
Aperture Spectrum  - Photo by © Reka Csulak

Aperture Spectrum - Photo by © Reka Csulak

Aperture's Impact on the Overall Exposure

  • Large aperture - small f-numbers - brighter exposure
  • Small aperture - large f-numbers - darker exposure

At this point, it is totally a logical question if you ask:

What if I want to have my background detailed using a small aperture that I don’t want to change, but the overall exposure becomes too dark?

To sort this out, you need to recall the memory of our exposure triangle. It’s time to re-create the balance by adjusting another setting (or both):

  • you can choose a longer shutter speed to brighten the image and/or
  • increase the ISO
  • if you are familiar with Photoshop, you can try to shoot multiple frames with larger apertures by moving the focus point all over the field for each photo and merging them during post-processing. This technique is called focus stacking.

And for sure, if you want to capture bokeh with a large aperture, and the exposure becomes too bright, you simply do the opposite:

  • you can choose a faster shutter speed to darken the image and/or
  • decrease the ISO
Background Bokeh - Photo by © Reka Csulak

Background Bokeh - Photo by © Reka Csulak

Foreground Bokeh - Photo by © Reka Csulak

Foreground Bokeh - Photo by © Reka Csulak

I invited a professional photographer friend to process this topic by digging deeper into the technical and creative use of our camera's aperture setting, so welcome Donna Crous on board!

Who are you and what is your photography specialty?

I'm Donna Crous, South African living in the UK. I started food photography about three years ago and have been working professionally for two years. My specialty is dark and moody photography, and I love working with a wide aperture and shallow depth of field.

Photo by © Donna Crous

Photo by © Donna Crous

What role your aperture setting play in creating a specific mood on your photos?

It's really important to make sure you have the correct aperture setting for the setting or type of shot. If I'm working on a cookbook then my publishers prefer more in focus to show the entire dish. For my personal images, I'll use a wider setting creating a shallow depth of field that makes a beautiful, romantic and soft mood.

Do you have a common depth of field choice as a core of your personal style?

Not really, it usually depends on the size of the main subject (being a glass, ice-cream or cake). I will also make sure to separate my subject from the background and other props, so as not to make the image feel full and busy.

Gorgeous Bokeh Effect - Photo by © Donna Crous

Gorgeous Bokeh Effect - Nikon D850 105mm, f/3.0, ISO 500, Shutter Speed: 1/200 - Photo by © Donna Crous

What are the minimum and maximum apertures of your favorite lens? Have you ever used the minimum or maximum f/ values of this lens?

I have three favorite lenses, 50mm, 85mm, and 105 macro. The 50mm and 85mm both go to f/1.8 and the 105mm goes to f/2.8, on the odd occasion I'll go to the minimum but in general I'll shoot around f/3 - f/5.6. I have never gone to the maximum so done even know how high they go.

What is your top tip to getting everything in focus even with dark conditions?

I don't often shoot in dark conditions, generally, my images are lighter and made dark in post-production. Definitely using a tripod is the way to go in dark conditions as lowering the shutter speed can result in movement and an out of focus image.

Aperture Choice for Flatlays - Nikon D850 65mm, f/5.6, ISO 200, Shutter Speed: 1/30 - Photo by © Donna Crous

Aperture Choice for Flatlays - Nikon D850 65mm, f/5.6, ISO 200, Shutter Speed: 1/30 - Photo by © Donna Crous

Be sure you check the beautifully curated gallery of Donna by visiting her