American photographer Stephen Eastwood took the time to shoot some portraits using various focal lengths, from 350mm to down to 19mm, in order to demonstrate the effects of focal length on perspective. For each portrait, taken with a full frame 35mm DSLR, he made sure to keep the framing the same – in other words, he moved closer or further away from the subject when changing the focal length.
For the entire range of images, visit his site and scroll sideways.
What’s happening here?
The radical change in perspective is caused by depth compression. If you shoot a portrait of someone from far away, the relative distance between their nose and their ears become minimal, let’s say 5% of the distance from ears to lens, which means that their entire face appears to be the same distance away from the camera, i.e. it looks flat. But if you shoot someone from 5 cm away, the relative distance between their ears and their nose becomes much greater, say 50% of the distance from ears to lens, and therefore the nose becomes much more prominent and the ears seem further away. The face starts to look distorted.
In other words, the focal length of a lens doesn’t cause the distortion, it’s the distance to the subject. So you might think that the best portrait should be shot at the longest focal length possible? Well, not really. At longer distances, the face becomes so “flat” that a pincushion type of distortion becomes a problem. The ideal would be a middle-ground, something closer to the focal length of our natural vision. Of course, none of this information should be considered as rules of photography – depending on the application, you can shoot portraits with any focal length and distance-to-subject you like.
So, which focal length seems the most natural to you? We would say that 100mm seems to be the most flattering in this case. Let us know what you think in the comments!
Via Dean Claassens (via StumbleUpon)