Telephoto Compression: Fact or Fiction?

Photography can be confusing. I get it. I am not the sharpest knife in the drawer. Because of this, at times it helps us to actually put some of these theories and myths to the test. One of these myths is the concept of compression and with it, parallax. This gets confusing to me as I am sure it does for some of you. Of course, there will always be the joker that knows everything and needs to let you know he knows everything. So this post is for the average, humble photographer that can’t seem to get their head wrapped around this concept of compression, distortion, and parallax. Let’s test this out.

But first, let’s define some terms.

Lens compression is the idea that when you use a telephoto lens things in the background of the image will appear larger and compressed closer to the foreground. It’s a bit like the warning of your side view mirrors on your car. An example would be if you have a row of pillars coming towards the camera. The pillars will not only appear larger but the distance between these pillars will seem to be more compressed when using a larger focal length lens.

Parallax is the apparent displacement of the position of the foreground with the background in an image. As an example, to use our line of pillars, the pillars in the background in relation to the pillars in foreground shifts to become visible. So the question would be when you shoot an image with a telephoto lens and then change to a wide angle lens will the parallax effect be seen?

These two concepts are linked. To the point, you really can’t talk about one without talking about the other. So, let’s look at parallax first before we move onto compression.

To test parallax I went out to my friendly neighborhood fishing village and made a series of photos of the Floating Mosque (it really isn’t floating, it rests on pillars over the sea). I stood in one location and shot a series of photos of the mosque focusing on the same spot in each photo. To make the photos I used two lenses, the Fuji XF 50-140mm and my Fuji XF 10-24mm. I took five or six photos at different focal lengths just in case I need them. But in the end, I only needed one image shot wide and one image shot with a relatively long focal length to uncover this mystery.

I then took these images and examined them for any signs of parallax. What was the verdict?

What we see is there is no parallax effect between lenses. But this will only happen if the photographer remains in the exact same spot. Why is this? Because the focal length does not change our relation to the subject. To do that we physically have to move. It’s basic physics, but we fool ourselves all the time to think there is a perspective shift between lenses use.

The only way you will see any change between the lenses we use and a shift of position between the foreground and background is when the photographer changes position nearer or farther from the subject.

I then took these images and examined them for any signs of parallax. What was the verdict?

The only way you will see any change between the lenses we use and a shift of position between the foreground and background is when the photographer changes position nearer or farther from the subject.

Now, let’s move on to lens compression. I hear photographers say how a telephoto will give you more lens compression than a wide angle lens. But I think you will see that the term “lens compression” is a bit of a misnomer. We do see compression when we use a telephoto, no doubt. But it has more to do with how or shall I say where we use the lens than the lens its self. We attribute the compression to the lens when in fact it is actually due to our physical distance from the subject. As in the photos above, where I photographed the same scene with two lenses of different focal lengths but never changed positions, there was no compression or better put, the compression was the same.

Where we see compression is when the photographer keeps the subject in relatively the same position in the frame between lens choices. Look at the images of the statue below. I tried as best I could to keep the upper body of the warrior in relatively the same position in each photo. Because I moved closer to the subject (changed spots) each time we finally see parallax and we see compression.

Actually, “focal compression” might be a better choice of words for this effect. But let’s face it, I am not going to change the industry’s use of this term. So let’s just say, lens compression happens in proportion to the distance from your subject and that it is more pronounced or easily seen in the use of a telephoto lens.

In closing, a related topic is bokeh or depth of field in relationship to telephoto lenses versus wide angles. To read about this visit my article Depth of Field Revealed. 

What do you think? Does seeing this played out above affect the way you shoot or lens choice? Let me know with a comment below.