Tilt-Shift Lenses (Part I)
Few things are more iconic of the older style of photography than that of the photographer using a view camera with a black cloth over their head. I know that when I was a kid, I viewed a serious photographer as one of those people.
Needless to say, things have changed quite a bit since the time that these cameras were “cutting edge”. The new features of today’s digital cameras are vast. Everyday, something new is released and unveiled to the general public, offering the consumer more megapixels and features than ever before.
There are, however, still a few things that the technologically advanced cameras of today could learn from the cameras that were popular, say, 100 years ago. One of the major advantages of the view camera is the ability to move both the front and back of the camera independently of each other. In this way the photographer is able to control both perspective and focus.
It is impossible to get this level of control in modern day digital cameras. It is possible, however, to come close and this is where the tilt-shift lens comes into play.
This will be a two-part article. In this installment I will talk about how a tilt-shift lens works and go more in depth about the tilting aspect of these lenses. In my next article, I will talk about the other feature of the lens – the shift.
There is one governing factor that allows the manipulations of a tilt/shift lens. This factor is how large the circle of light coming in from the lens is.
Here we can see an estimation of the light circle on a normal (non-TS) lens. The red box represents the size of the sensor in the back of your camera. Notice how the circle of light falling on the sensor is just large enough to fully cover the sensor.
On the right, we have an estimation of the size of the circle of light on a tilt-shift lens. Notice how much larger the circle of light is, thus allowing the lens to move quite a bit in any direction while still keeping the entire sensor within the lit area.
Let’s quickly summarize the two elements of these lenses and how they work:
Tilt: Tilting the lens (described more in depth below) allows the photographer to adjust the plane of sharpest focus in the image. On all lenses that are not tilt-shift, the plane of focus is parallel to the film or sensor.
Shift: Shifting the lens will be our main topic in next week’s article. For a quick summary: shifting gives the photographer the power over perspective in the image. One of the basic abilities shifting gives you is to make it possible to correct for converging lines on buildings by minimizing the need to shoot up your subject.
Tilting the lens gives the photographer the power to manipulate the “plane of focus” in the photograph.
Normally the “plane of focus” in a photograph stays exactly parallel to the film or the sensor. This means that as we increase the depth of field, more comes into focus in front of and behind the subject.
With a tilt-shift lens, we are able to change this plane of focus, moving it from parallel to the sensor to nearly perpendicular. This allows the photographer to create a “sliver” of focus through any part of the image.
Using tilt movements to reposition the Depth of Field:
The maximum depth of field (smallest aperture such as f/22 or f/32) we can get out of our lenses is in many cases not enough to truly get from the foreground to the background perfectly sharp. Also, as most of us know, when we push our lenses to those smaller apertures, we are sacrificing sharpness in our photograph.
With a tilt-shift lens, however, we can shoot on a fairly large aperture, such as f/4 or f/5.6 and still be able to get front to back sharpness. This is done by tilting the front of the lens downward, which in turn moves the focus plane from parallel to the sensor or film, to almost parallel to the ground (see drawing below).
Here we can see a comparison between focus on a normal lens and a tilt-shift lens.
As I have shown, this technique can be used in a practical way to give the photographer virtually limitless depth of field. It can also be used creatively.
Tilt-shift lenses have the ability to rotate, meaning that you don’t always have to tilt your lens up or down. You are also able to tilt it side-to-side, or along any diagonal in between. This allows you to do cool effects by kicking the focus out on both sides of your subject, leaving it tack sharp in the area you want to emphasize (see example photos).
When you buy a tilt-shift lens, you are buying the ability to have FULL control over what’s sharp in your photograph. This can be used to give you unlimited depth of field in your image, or to minimize what is sharp, leaving the rest simple and uncluttered.
Below, you will find some example images I have taken using these techniques.
Next time: More info on Shifting!