Part 1: Will Learning Tilt-Shift Lenses Improve Your Photography?Gear Talk
John Cooper specializes in corporate, industrial, and commercial photography for various business communities in Texas and teaches basic skills to other burgeoning photographers. If you are just starting out, or looking for a refresher, check out his advice below. You can also read more tips for architectural photography from John on our blog. Here is his advice on whether tilt-shift lenses are worth it for photographers.
Are tilt-shifts worth it? It depends on what ‘it’ is. Most will argue that software editing can replicate the effects of a tilt-shift lens – so why bother?
We need to first understand three key facts:
An SLR camera focuses to a plane, not a point, even though you can select the precise place you want to focus on.
Depth-of-field and depth-of-focus (DOF) mean the same thing in this discussion. The slight difference between the two does not affect the tilt-shift principles discussed here.
The only way to control DOF on any SLR camera without a tilt-shift lens is by aperture.
The sketch below shows how the Sensor Plane (SP) is always parallel to Plane of Focus of the lens. This remains constant for all lenses except on tilt-shift lenses.
All SLR camera lenses, except the tilt-shift lenses, focus ONLY “front-to-back”. Whatever position your camera is in, relative to the subject, will produce a DOF “plane”. If your subject is parallel to your camera’s sensor plane, then everything will be in focus. If your subject is on a diagonal then only the plane you focus on will be sharp.
The images below illustrate the “front-to-back” DOF control by adjusting the aperture.
Above is an example of opening up the aperture to decrease the DOF.
Most of you already know that this is all photo-101 stuff but this review will be helpful later.
Canon and Nikon produce the most common tilt-shift lenses. All tilt-shift lenses have the same basic controls and functions. You can tilt and/or shift the lens relative to the fixed plane of the camera’s sensor. The following explains each function.
The shift function is the easier of the two to understand.
The shift function allows the lens to be moved (shifted) left or right and always remain parallel to the camera’s sensor plane. There is a button you can push that allows 360° rotation of the lens along its optical centerline. That means that the lens can be shifted in any angle desired and remain parallel to the sensor.
The most common use of the shift function is to correct convergence.
Convergence correction: Assuming you are shooting buildings or tall objects, rotate the lens 90°. Now the shift knob moves the lens up and down. Shift the lens up to where you want it and there you go. I suggest leaving a little convergence since that is the way our eyes see it.
Here is a classic example of the shift function:
I shot this in 2008. It was, at the time, the south entrance to the Texas Medical Center. The location of the center is in a very dense area. My assignment was to capture the building (Texas Women’s University School of Nursing, Kirksey Architects) in context with the “Twin Syringes Tower” by Cesar Pelli in the background.
I set up at around 100′ from the curb on the opposite side of the street. Visualize this set-up and you should quickly see that capturing the building without distortion and foreground interferences was a very tall order. The tilt-shift allowed me to correct convergence. To do this place the plane of focus parallel to the right side of the building and shift the traffic lights out of the frame. Those actions are not possible with standard lenses.
Above is an example shot with the 17mm tilt shift. I was very close to the brick and stone wall on the near right of the frame. The frame was as distorted as one could imagine. Shifting the lens up allowed the full frame to be composed without cropping or software editing. Shifting the lens left allowed great focus in the lobby without being a straight-on shot.
In addition to the common practice of shifting up to correct convergence, you can also shift right-to-left to avoid visual obstructions in the foreground. The above was an assignment where the client wanted to show how the playground was connected to the school on the left. The tall light pole spoiled a straight on shot, so I moved my gear to the left. I set up and shifted the lens to the right and got the shot I wanted.
Both the tilt and the shift were used in this photo. The shift provided the desired exaggeration of the cantilevered second floor as well as the convergence correction. The focus plane is shifted slightly to the right to provide the focus I wanted and tilted slightly down to place the focus plane parallel with the base of the wall. The plane of focus runs from the right side of the frame at a diagonal into the frame and parallel to the wall.
The tilt function allows you to tilt the lens instead of moving the lens around in a flat plane parallel to the sensor. Using tilt makes it so the focus plane of the lens is no longer parallel with the sensor.
With tilt-shift lenses, the way you focus jumps into the 3-D world. The focus ring on the lens is only half of the focusing process. The angle of tilt now becomes the other part of focusing. The focus plane floats wherever you place it and on any axis you desire. Imagine a piece of plywood floating around in your scene. Only the plane of plywood can be in focus. After much trial and error you will start to see the focused plywood in the frame. Once this happens you can dial it to where you want it. The plane of focus (the plywood) no longer lives in the front-to-back world. It can traverse diagonal into your composition on any of the 360° planes you wish.
As with everything photographic, tilt-shift properties are based on hard science. The Scheimpflug Principle states: “When the extended lines from the lens plane, the object plane, and the film (sensor) plane intersect at the same point then the entire subject plane is in focus. It helps to explain how the lens behaves the way it does. It may or may not assist you in applying that knowledge to achieve better photography.
My experience has been that trial and error works better than pre-calculated charts of settings. For me having the tilt-shift effect intuitively in my mind is more rewarding in the long run. Even if you don’t understand the principles now, try one out for yourself and see the difference.
Most tilt-shift images are currently associated with miniature appearing images. That is not the topic at hand but it does provide insight into what the focus plane is and what happens when it is tilted relative to the camera’s sensor. The shot below was an accident. Let me repeat that: the shot was an accident. But it proves two very important points:
- You never really learn anything until you mess it up.
- You WILL make mistakes if you’re attempting to use a tilt-shift lens.
This miniaturization effect is caused by the focus plane being tilted to create only a narrow slither of vertical focus. That narrow plane where things can be in focus makes everything else in the frame blur immediately. This notable contrast of focus against blur causes us to see “miniature”.
Here are some images I shot with the 17mm tilt-shift lens:
So what can you do with tilt-shift that you cannot do with post capture software? I can place the plane of focus in a location that I compose – a location that enhances the photograph optically. This optical precision is sharper than software. I use tilt-shift lenses and have learned more about photography as a result. However, they are more trouble than they are worth to me unless a client wants large display shots. And even then I would probably shoot it both with tilt-shift and another L series wide angle.
Reasons to Use a Tilt-Shift Lens
- It improves your understanding of all photography.
- Optical correction is higher quality than post capture software editing
- If done correctly, there are few photographs as stunning as a tack-sharp tilt-shift print that is 3’ or 4’ wide and displayed prominently.
Reasons Not to Use a Tilt-Shift Lens
- They are manual focus only.
- You must use a tripod.
- You must use the live display feature to focus.
- They are expensive.
- The quality differences are minor unless enlarged greatly and printed. Their use in projected digital images is noticeable but the large prints are where it shines.
These are my views and not everyone will agree. The beauty of BorrowLenses.com is that we are allowed and encouraged to have our own opinion, share it, and even change our minds after renting a few new pieces of gear. Stay tuned for part 2. In the meantime, learn more about the basics of these special lenses.
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