With a Tilt-Shift lens, many things modern photographers do with Photoshop can be done in-camera, but without loss of pixels, without distortion, and simply better. The few people that do own one are usually photographing architecture, but so much more is on offer when you understand this lens's capabilities. Some of the uses are as follows:

• • • Fixing perspective on tall buildings (most common use)
    • Miniaturisation effects (what most people think of)
    • Creating distortion-free panoramas (less well known)
    • Landscapes with true front to back focus (rarely used)
    • Product photography (aligning the focal plane to the subjects)
    • Dream-like portraits (specialist photographer trick)

To fully understand these lenses you need to understand what they are doing and how they achieve it, so it's back-to-school time.

The base of the lens has a square block section with a wheel on each face. Opposing sides provide an adjustment wheel and a locking wheel for both the Tilt and the Shift actions. The whole of the block can be rotated so that the tilting and shifting can take place either horizontally or vertically depending upon the requirements of the shot.

As can be seen from the animations above, the lens either shifts up and down or tilts up and down. Hence the name.

Shift Mode

A regular lens throws a circular image onto the sensor. The circle is sized such that the corners of the sensor all touch the circumference of the circle. When you press the shutter the sensor captures the area of the lens circle that is landing on it. In the case of a Tilt-Shift lens, the projected circle is much larger than the sensor and by shifting the lens you are capturing different portions of the projected image. When capturing a photo of a building, with a normal lens, you may have to angle the camera upwards to capture the full height of the structure. This causes vertical lines to converge and make the building appear to be falling backwards. With a Tilt-Shift lens, you position it horizontally, so that there is no convergence, but then use the shift-plane to move the lens upwards to capture the full height without deviating from the horizontal orientation, which is why this lens is so favoured for architectural work.

When it comes to landscapes, we are all familiar with taking a series of overlapping shots and stitching them into a panorama. Photoshop does an admirable job of creating a great pano. However, there will be significant distortion and a large portion of the original pixels will need to be cropped to address that issue. In the case of very wide panoramas, horizontal lines can have a pronounced curve to them.

Mounting the camera on a tripod and using the Shift axis horizontally you are able to capture a trio of overlapping images with zero distortion. that can be stitched together without compromise, which is one of the reasons why this lens is favoured by landscape photographers.

Tilt Mode

Explaining what the tilt function does is a little trickier and involves an understanding of the beautifully named Scheimpflug Principle.

With a normal camera and lens, the focal plane is always parallel to the plane of the sensor. When you focus on a point, everything a similar distance from the lens will be in sharp focus. The depth of focus, as controlled by the size of the aperture, will dictate how far in front and behind the focal plane objects will also be in focus. Nothing odd about any of that.

The tilt mode of a Tilt-Shift lens allows you to change the angle of the plane of focus so that it is no longer parallel to the sensor while retaining all the normal control of the depth of field via the aperture. This offers tremendous creative opportunities. That was probably difficult to grasp at first reading so here's a diagram that may help.

In the diagram, I have shown a trio of points of focus and their associated planes of sharp focus. As you can see the further out you focus the more parallel to the ground the focal plane becomes. This makes a Tilt-Shift lens perfect for front to back sharpness of landscape shots. No need for focus stacking with this kind of lens.

Once you understand the principles the creative possibilities are endless. You could photograph the row of chairs and have the seat tops in focus, while the backs and legs are out of focus. You can shoot along the face of a large painting and have it in perfect focus, while the people standing viewing it are out of focus. You have total control of where and what is in focus in your image

Faking It

We have all stitched together panoramas using Photoshop, and providing that the subject is far enough away we can create quite a nice image. When shot with a Tilt-Shift lens you create a far better image, with zero distortion and no loss of pixels due to excess cropping.

We can use Photoshop to straighten vertical lines on our architectural shots, but there will be a loss of quality due to the stretching and compression of pixels in the image.

Even with the smallest of apertures, we can't quite get the true front to back sharpness we can obtain from a Tilt-Shift lens. This is why it is sometimes necessary to focus-stack a landscape shot.

The miniaturisation effect can easily be recreated in Photoshop, either manually using a blurred layer and mask, or by using the new Blur Gallery option for Tilt-Shift. To be fair Photoshop is a better solution for miniaturisation then the Tilt-Shift lens option, but that's not really what they were intended for.

And finally, a few fake miniatures created by hand in Photoshop.