Photographing at a very wide aperture is usually associated with a strongly blurred background and a very shallow depth of field. But does F/1.4 always mean that only a small part of the subject will be sharp?
I decided to check this in practice. I used a Canon EOS R6 Mark II and Canon RF 85 mm F/1.4 L VCM, with Lola as the model.
This is not a laboratory test. I was interested above all in what we see in normal photographic work: how depth of field, subject separation and the character of the image change with different apertures and different distances from the subject.
I started from a short distance — around 1.5 m — with the lens wide open at F/1.4.
With this combination, depth of field is extremely shallow. The eyes can be sharp while the nose, closer to the camera, is already outside the sharpest zone. At the same time, the background becomes heavily blurred and practically stops competing with the subject.
It clearly shows how demanding F/1.4 can be at close range. Precise focusing becomes essential.
I did not change the aperture — it was still F/1.4 — but moved back to around 2.5 m.
The effect is very interesting. The background remains strongly blurred and Lola is clearly separated from it. At the same time, a larger part of her head falls within an acceptably sharp range.
This is where it becomes obvious that depth of field is not determined only by the number next to the letter “F”. The distance between the camera and the subject matters just as much.
The next image was still taken at F/1.4, this time from a distance of around 4 m.
The difference from the 1.5 m photograph is striking. Despite the identical aperture value, depth of field is greater. Thanks to the 85 mm focal length, the background still remains soft and clearly separated from the subject.
For me, this is one of the most important conclusions of the comparison: F/1.4 does not always have to mean an extremely shallow depth of field. As the distance from the subject increases, the area perceived as sharp also becomes larger.
The second part of the comparison shows something different. This time, the distance is about 2.5 m and the aperture changes.
I compare F/1.4, F/2 and F/2.8.
At F/1.4 I get the shallowest depth of field and the strongest separation between the subject and the background. The background is very soft, and attention is drawn automatically to the model’s eyes and head. An example is shown above.
When the lens is stopped down to F/2, depth of field begins to grow noticeably. A larger part of the head lies within the sharp range, while the background remains strongly blurred.
In practice, F/2 can be an excellent compromise between the distinctive look of a fast lens and a greater margin of safety when focusing.
At F/2.8, depth of field increases further. That does not mean that the characteristic look of an 85 mm portrait suddenly disappears.
The background is still clearly blurred and the subject is well separated from it. What I gain is more freedom when I want to keep a larger part of the head sharp.
This comparison highlights something that is easy to forget when discussing fast lenses: the appearance of depth of field is influenced by more than aperture alone.
The distance from camera to subject, focal length, and the distance between subject and background are all hugely important.
That is why two photographs taken at F/1.4 can look completely different. At 1.5 m the sharp zone is extremely small. At 4 m, the same aperture gives a much larger sharp area while still allowing strong background separation.
I do not treat F/1.4 as a value that has to be used simply because the lens makes it possible.
For a close portrait, F/1.4 creates a distinctive effect but requires great focusing precision. At a greater distance, using F/1.4 becomes much easier.
F/2 gives a little more margin for error while preserving strong background separation. At F/2.8, depth of field increases further, but at 85 mm we can still achieve beautifully soft background blur.
The choice of aperture therefore depends above all on the effect I want to achieve and the distance from which I am photographing.
This simple test confirmed that when using a fast lens, it is not enough to look only at the aperture value.
F/1.4 offers enormous possibilities, but distance from the subject can change the character of an image just as strongly as changing the aperture itself.
At 1.5 m, F/1.4 means a very shallow depth of field and requires precise focus on the eye. At 2.5 m the situation becomes much more comfortable. From around 4 m, I can still use the characteristic F/1.4 blur while gaining a much larger zone of sharpness.
F/2 and F/2.8 are not “worse” settings to me. They are simply additional tools that let me decide how much of the subject should be sharp and how strongly I want to separate it from the background.
And that conscious choice between F/1.4, F/2 and F/2.8 is, for me, one of the greatest advantages of photographing with a fast 85 mm lens.
