Understanding Lens Compression
You may have heard of this telephoto characteristic, but how does it work?
Lens compression, or telephoto compression, is a visual effect that can change the apparent size of a distant subject relative to a nearer one, making them appear closer together than they are. Knowing what it is and how it works is crucial to building a full understanding of perspective in photography, so read on to get to grips with this imaging phenomenon.
What is lens compression?
For a given image sensor, the size an object appears in a photo depends on three factors: the actual size of the object, the distance between the object and the lens, and the lens’s angle of view.
Lens compression refers to an effect typically observed at longer focal lengths, or narrower angles of view, in which the distance between two objects is smaller in proportion to the distance between the objects and the lens.
In the resulting image, this has the effect of ‘compressing’ the distance between the two objects, making them appear closer to each other than they actually are.
Why ‘lens compression’ is a misnomer
Technically speaking, this compression is simply a characteristic of perspective – and has nothing to do with lenses!
Imagine two identical objects are spaced ten metres apart. If you stood ten metres from the first object, the second object would appear 50% smaller (10 ÷ 20 = 0.5) than the first. This is because the apparent size of the object is directly proportional to its distance from the lens (your eye, in this example).
If you stood 100 metres from the first object, the second object would appear only around 10% smaller (100 ÷ 110 = 0.909), and the distance between the two would appear much smaller.
What this means is that compression is a result of camera position. It can be achieved with any lens – but it’s harder to frame photos in a way that draws attention to it with a wide-angle lens.
In the example below – a wide-angle landscape photo – we have shown the original framing, then cropped in to achieve a tighter perspective. In the cropped version, there is a clear compression effect: trees an entire field away from each other appear a similar size.
While that’s also the case in the uncropped version, it’s not the focus of the photo. An extreme crop is required to highlight it, which is only possible with a sufficiently high-resolution sensor and high-resolving lens.
The more practical way to achieve this framing is with a telephoto lens, which is why the effect is commonly referred to as telephoto compression.
How to use lens compression
Once you’ve got your head around how telephoto compression works, there are countless ways to deploy it creatively in your photos and films.
You might want to emphasise the size of a background element, making the environment appear bigger in relation to your subject. Alternatively, compressing the distance between subjects in a busy scene can create an impactful sense of chaos.
Once you know what you’re going for, simply back up and zoom in until you’ve achieved the intended framing. To this end, using a zoom lens or teleconverter can be helpful, so you can adjust focal length until your frame depicts the desired degree of compression.
Try these optics for the X Series:
- FUJINON XF55-200mmF3.5-4.8 R LM OIS
- FUJINON XF70-300mmF4-5.6 R LM OIS WR
- FUJINON XF100-400mmF4.5-5.6 R LM OIS WR
- FUJINON XF150-600mmF5.6-8 R LM OIS WR
‘Wide-angle distortion’ and portraiture
You may have heard that longer lenses (usually 85mm full-frame equivalent and above) are best for portraiture as they give a more flattering depiction of facial features, whereas wide-angle lenses impart distortion that makes features appear further apart.
As before, this is not actually a characteristic of any particular lens or focal length, but a result of your camera’s distance from the subject. When your camera is further away, the perspective compresses the distance between features. Get closer, and the compression effect is reversed – features appear further apart.
Your choice of focal length only affects what fits in your photo. If you wanted to fill your frame with someone’s face while ensuring your camera was far enough back to achieve a flattering level of compression, a mid-telephoto lens like the FUJINON XF56mmF1.2 R WR or XF90mmF2 R LM WR would be a good choice.
Take the photo from the same perspective with a wider lens, and you’ll have the same compression, though your subject will appear smaller in the frame. Wide-angle lenses don’t inherently change the shape of a subject’s face; getting too close does.
Understanding this distinction is crucial to avoiding perspective distortion when photographing people. Wide-angle lenses are great for environmental portraits, and wedding photographers make frequent use of them for this because they know you can take flattering photos of people with any lens – you just need to be stood in the right place.
Learn more with FUJIFILM UK
If you want to learn the theory behind more photography and filmmaking techniques, you’ve come to the right place.
Head to the FUJIFILM Learning Centre home page to explore articles covering a range of imaging genres and levels of experience.
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