Depth of field

What is the depth of field?

This is the area of the image in which the objects are sharp, i.e. the area of sharpness or focal plane. We can also say that it is the distance between the first net plane and the last net plane of the image.

What is important to notice is that the background blur (bokeh) is becoming increasingly important as you move away from where you made the focus, that is to say the area of sharpness.

The hyperfocal distance

The hyperfocal distance makes it possible to find the largest area of depth of field with sharp subjects to infinity. Often used for street photos, the use of the hyperfocal dispenses with any other focus (no auto focus / AF). But some objectives devoid of focus mark don't allow applying this method of work.

Use

1. Set the focal length and aperture you want by turning the wheel or by clicking to enter the value

2. Set the unit of distance you want (cm, m, km, in, ft, yd, mi)

3. Set your focus distance

In the part "Depth of field"

4. You get:

Tips

Maximise the depth of field

To obtain a large depth of field, you must:

Minimise the depth of field

To decrease the depth of field, you must:

Depth of field for portrait

For a medium or close-up portrait, the focus is on the eye with a sharpness area from the tip of the nose to the ears (or the hair). The choice of an average aperture such as f/5.6, for example, makes it possible to obtain this result while maintaining an aesthetic background blur.

A or AV exposure mode

Even if all the modes lead to the desired result, the aperture priority exposure mode: A or AV is the preferred mode for choosing the aperture and therefore defining the depth of field. To avoid motion blur or camera shake, you can choose to work with the ISO auto and possibly set the minimum speed to keep.

Maximum sharpness

Maximum sharpness indicates, for a given focal length and focusing distance, the aperture that will give maximum sharpness around that focus, while maintaining foreground and background blur. This maximizes the sharpness of the subject, while maintaining the correct front and back blur for the focusing distance.


Illustration (with a full frame sensor):

Subject at 2 m with 50 mm focal length and 3.5 aperture

Blur from 0 to 1.85 m in front and from 2.18 m to infinity behind, i.e. a depth of field of 0.33 m.

The tool indicates an aperture of 8.7 (which we'll approach at an aperture of 9.0) for maximum sharpness in front of and behind the subject.

We'll have blur from 0 to 1.65 m in front and from 2.53 m to infinity behind, i.e. a depth of field of 0.88 m


To obtain a front and back blur almost identical to a 3.5 aperture, but with greater sharpness, we can reduce the aperture to the maximum, up to 8.7


The reverse calculation method

The tool allows you to do the reverse calculation to find the aperture needed to obtain a given depth of field or hyperfocal.

To obtain the aperture value, all you have to do is enter the desired depth of field or hyperfocal value in the fields.

The principle of Bokeh

The term "bokeh" is derived from Japanese "boke" (ボ ケ), which means "fuzzy" or "haze". Bokeh is the pleasant or aesthetic version of the blur in photography.

If Bokeh is a photographic feature, the shape and size of this effect is determined by the lens used. Bokeh varies according to the shape of the lamellae of the lens diaphragm. A lens with circular slats will give blurry orbs with rounded shapes, while a lens with a hexagonal aperture will give blurred orbs with hexagonal shapes.

How to create a Bokeh in your photos?

To get a Bokeh effect in an image, you must use a light lens. The brighter the lens, the more successful the effect will be. Opt for a lens with a minimum aperture of f/2.8.

You will need to shoot with your lens in full aperture. It is therefore advisable to select the Aperture Priority or Manual mode.

Your lens is not very bright? This is not a problem. Increasing the distance between the background and the subject makes it possible to create a Bokeh effect in photos made with small apertures.

To emphasise Bokeh in your photos, increase the distance between your subject and the background. To do this, reduce the distance between your camera and the subject. The lower the depth of field or the farther the background, the fuzzier the background will be. A brightly lit background will also accent the Bokeh. A backlight, a side light or a backlight will give a Bokeh more enjoyable to watch.

Close-up portraits are particularly conducive to the Bokeh effect. Bokeh is also frequently used in macro photos and close-ups of flowers and other elements of nature. Christmas lights or other highly reflective objects turn into luminous orbs in intentionally fuzzy shots.

Bokeh adds sweetness to a very bright picture. By detaching your subject from the background, this technique also allows you to use a low photogenic background. Thanks to its diffuse blur, the Bokeh highlights the subject instead of diverting the attention of the latter.

Use

1. Set the focal length and aperture you want

2. Set the unit of distance you want (cm, m, km, in, ft, yd, mi)

3. Set your focus distance

4. Set the distance from your foreground to the lens

5. Set the distance from your background to the lens

In the part "Bokeh simulator"

6. You get: