Exploring How Focal Length Affects Images
Tutorial Details
- Difficulty: Easy
- Equipment: Lenses with focal lengths ranging from wide to telephoto
Have you ever stopped to think about the way focal length affects the aesthetic of an image? Even if you’re photographing the same scene, selecting different focal lengths can really reshape the aesthetics of your scene. Zooming in and out on the same subject area greatly changes the way that a subject relates to the background and the perceived distance between the two.
Subject to background compression is a powerful effect of longer focal length lenses. Long lenses have a way of flattening images, while wider lenses exaggerate perspective. Ever wonder why an 85mm lens is such a popular choice for portraits? This lens has a nice “flattening” effect on the face that ensures that the nose and other facial features are not larger than life.
While some people hesitate at the thought of using prime lenses (lenses with a fixed focal length), moving your feet and altering composition is all you need to make a great portrait. For most of my portraits, I prefer lenses of a longer focal length, typically a 50mm or 85mm lens. This is for a number of reasons. The first of these being that it serves to flatten the subject. We can hide or lessen geometric facial differences with big telephoto lens. The flattening effect on body features is complimentary to your subject.
Using a long focal length also affects depth-of-field. As you probably already know, the term depth-of-field refers to distances from the camera that are in focus. Although many people assume that depth-of-field is solely related to the aperture of a lens, focal length has just as much (if not more) of an effect on the depth-of-field. With a longer lens, the depth-of-field is reduced, thus throwing the background more out of focus and isolating the subject.
Often, this is an desired effect for portraits. In choosing a longer focal length, you can isolate the area occupied by the subject and shift the viewer’s focus on the subject. Conversely, greater depth of field through use of wider focal lengths helps to include the surrounding scene.
However, there is never one best lens or focal length choice. If you’re wanting to show how a subject relates to the background, using lenses of different focal lengths can change the way the background appears in relation to the subject.
To illustrate this, I shot a series of test images on a bridge near my house. Notice in these images how the bridge’s appearance changes in relation to the model.
I used a variety of focal lengths in order to illustrate this effect. The first lens was a Tokina 12-24mm f/4 lens. The second was a Nikon 35mm f/1.8. The final lens was Nikon’s 80-200mm f/2.8 lens at 100mm and 200mm. The lens tests were all shot at f/2.8 to equalize depth of field effects (with the exception of the Tokina, set at f/4).
(Note that these shots were taken on my Nikon D300 and that there is a focal length modifier because it is a DX-format camera)
Let’s take a look at some test images. In each of these shots, I attempted to compose similarly, with the model’s body nearly filling the frame top-to-bottom. Notice that while she occupies approximately the same amount of space in the photo, the background is greatly altered. Most noticeably, you’ll observe that the relative size of the bridge in the background changes greatly across the focal length spectrum.
This first shot was taken at the widest perspective, 12mm, using my Tokina 12-24mm lens. In this shot, notice that all of our perspectives are exaggerated. The lines on the road lead into the background with the bridge. The bridge can just barely be seen in this photo! The ultra wide perspective also greatly increases the depth of field, as you can see almost everything in focus. With this focal length, we’ve included the entire scene.
In this shot at 35mm taken with Nikon’s 35mm f/1.8 lens. This is a midrange focal length. The bridge is now more within our viewing range, and depth-of-field is somewhat less than our 12mm shot. We are still at a fairly wide focal length, but have somewhat zoomed into the scene and have begun to isolate the subject.
Alright, now we’re at a sweet spot for portraits, sitting at 100mm on Nikon’s 80-200mm f/2.8 lens. Notice that in this photo there is a definite “flattening” effect for the model. The bridge is appearing much closer to the model and we’ve diminished the leading lines of the road. We are now also starting to elminate the depth-of-field, and thus isolate our subject further. This is a focal length that I typically will shoot for when shooting either waist-up or headshot portraits.
In this final photo, that same lens is now set to 200mm. The subject to background compression is in full effect and our model appears very close to the bridge in comparison to the 12mm shot. Notice that we now have a very shallow depth-of-field and our model is very isolated in relation to the scene. Although we are showing the same subject matter, the differences in focal length have created two scenes entirely different in appearance.
Conclusion
In this tutorial, I have attempted to show you the different advantages that varying focal lengths offer. The test images illustrate that the focal length of a lens can reshape a scene.
Experimenting with these various focal lengths is a powerful part of the creative process. Focal length choice is a huge part of the composition process of an image. You can use a wide lens to lead into a background or create distance, or choose a longer focal length to compress your subject against the background. A focal length of any choice can be a good one depending on the way you envision the scene.
Please share your opinion of the test images above in the comment. Did you prefer the wide angle shot, the telephoto shot or something in between? Also share your tips for choosing focal length.
Enjoyed this Post?
Subscribe to our RSS Feed, Follow us on Twitter or simply recommend us to friends and colleagues!
By Andrew Childress
Join our newsletter!
Create a Tutorial, Get Paid!
Have something to teach the world? Want to earn money doing it? Tutorials, screencasts, and articles published here on Phototuts+ are largely contributed by readers just like you! We'll pay you great money for good content. Find Out More
Thank you for the tutorial! It was quite educational and nicely illustrated :)
Even though I’m usually a big fan of a very shallow depth-of-field, I prefer the 12mm shot!
The clear lines to the (seemingly) far away bridge in the center are very beautiful, but not distracting from your model (which seems to struggle with the wind ;) ).
Furthermore I think the contrast and the colours are just perfectly balanced.
Too bad, there are those drainages and overhead lines, but I still love this shot.
cheers from germany
You could still achieve this look with a smaller aperture which would give you the same depth of field, but the distortion on the model would be less than the 12mm shot, which would be more flattering for the model. We should show the effect of just focal length without depth-of-field changes in the image so you can really see what focal length does to distortion of the image.
It would be interesting to know how far away you had to stand for each shot.
This is something I’ve always wondered about when people talk about the effect of focal length on perspectives and portraiture: you get the perspective difference by moving away, right?
In order to maintain the same framing for each shot, as he zoomed in he had to step back. Interestingly, the closer you stand to your subject, the shallower the DOF will be, especially with telephoto lenses. This will also compress the image proportionately too.
For example:
http://d2f29brjr0xbt3.cloudfront.net/529_flashfunctions/-5.JPG
was f/4 @ 200mm (Canon EF 70-200mm f/4L IS USM). I stood as close as possible to drop off the background as much as I could.
In this example:
http://d2f29brjr0xbt3.cloudfront.net/343_pope/-8.JPG
I was much farther away and even at f/2.8 @ 200mm (Canon EF 70-200 f/2.8L IS USM), notice how much more DOF there is.
I found this tutorial, particularly the pictures quite a useful illustration of the power of focal length. I have seen others done but this was quite comprehensive. I will suggest it to my novice photography friends.
I’m afraid you’re wrong, because you forget one thing : the distance from your subject changes between shots. In fact, it’s this distance which changes the perceived distances between subject and background.
Try to take the same shot at different focal lenghts, but instead of moving to get the same framing, crop the pictures. You’ll see that the perspective doesn’t change !
Obviously, you can’t crop images for real, so depending on your focal lenght you have to move. But this is explaining why something like 50mm is best for shooting an entire person, and 85/100mm for shooting just the face : this longer focal lenght allows to stay away from your subject and not distort perspectives too much.
This is a great well thought out tutorial. I have always been able to grasp this concept but I think with your images and the way you explained will help many others who are new and learning. Great job on this, thumbs up!
I am in agreement with Kris. Would you mind sharing the distance you were from the model at each focal length? I know the tutorial is showing how the focal length affects the subject in relation to the background, but maybe humor us as a little bonus material? Would be greatly appreciated.
I also forgot to say, nice tut. Its hard to find tutorials that show step by step comparisons of things like this.
I like the unusualness of the wide one.
Thank you so much for this wonderful post. I was just asking myself this exact question the other day, as I was not getting that much depth of field change out of aperture settings on a lens I was using.
Please keep up the fantastic work.
I’m still learning and trying to understand some concepts of photography and I was recently discussing this. I was wondering if my logic is correct. Focal length and DOF is basically like a ruler. the smaller the ruler (focal length) the smaller the ticks (DoF) you have to work it. So for 200mm you have greater distance to focus between subject and infinity for greater DoF.
Great tutorial thanks. Love the first pic best for the overall composition.
OOO Thanks… very clear post.
Hence the reason my back is broken carrying that Canon Ef 70-200 F2.8 is mkii for up to 8 hrs.
But its so worth it. and your shots prove a great point in Lens choice as well as depth of field.
Great shot on the wide angle. Gosh I wish I cld get one of those
Depth of field is the distance in front of and behind the subject that is in focus. I think you’re saying the same thing when you said “dof refers to the distances from the camera that are in focus” . It’s the camera part that threw me a little. Love Photo-tuts. Keep up the good work!
Thanks everyone for the kind words and feedback!
Wonderfull tutorial for the power of focal point and how is can influence the overall exposure. I love the wide angle (12mm) pic, it is the best since the DOF i wonderful and the fact that wide angle creates greate depth and non flattened exposure. Also the contrast and shapness is distinguished in that pic. However I wonder how I was just taught (I am a beginner attending my first photography course), I was just taught that the best framing for portrait may be obtained by focal length ranging from 85 to 135, this contradicts that I see here the best pic – which is for a person, meaning portrait – is for a much smaller focal lens. Seems that it is not a rule !