Photography with Tilt and Shift Lenses

Chapter 1

Introduction to Tilt/Shift Lenses

THE TILT/SHIFT LENS

Lenses with tilt and shift movements are somewhat of a mystery to all too many photographers. The sideways or up/down movement of shift and the 'bending lens' look of tilt hark back to the earliest days of photography and large cameras with sheets behind them and ground-glass focus screens. For photographers used to modern digital DSLR and mirrorless cameras, the fact that such lenses on their cameras are largely manual in operation can also be disconcerting.

In reality, using tilt/shift lenses has never been easier, with instant feedback via rear screens, and features such as focus-peaking and electronic viewfinders. These allow the setting of both shift and tilt to feel much more intuitive and accurate. It is easiest to look at lens shift to start with, and then aspects of tilt. The two functions can, of course, be combined, but knowing what each does on its own is important to appreciate.

The steps up to the chapter house at Wells Cathedral. Using a lens shifted upwards has allowed retention of true vertical lines whilst shifting the view of the level camera upwards. Inspired by a famous photo of the scene by F. H. Evans in 1903, who would have used similar lens movements, albeit with a much larger camera and simpler lens design.

The mechanical complexity of tilt/shift lenses can be confusing at first. A simple approach looking initially at shift and then at tilt can give an intuitive understanding of how the capabilities of the lenses can be matched to a photographer's vision.

TILT/SWING/SHIFT/RISE/FALL?

This book assumes that the main audience will be photographers, probably using shift or tilt/shift lenses on DSLR or mirrorless cameras, typically with 35mm 'full frame' or 'FX' sensors. However, examples have been included from smaller APS-C and larger medium-format cameras. When reading, it can be assumed that any reference to movement using the tilt setting of a lens is to tilt, whether up/down, left/right or a combination of the two. Traditionally, left/right movement is referred to as swing. Similarly, any movement of the lens shift control is referred to here as shift, rather than the alternative rise/fall for up/down movements.

Using a lens adapter, this medium-format lens is shifted downwards by 15mm. This downwards shift is sometimes referred to as 'fall' as opposed to 'rise' for upwards movement - for simplicity, any direction of shift in the book will be referred to as 'shift'.

Whilst there are links to resources covering a fuller mathematical description of tilted lenses, such an approach has been quite deliberately avoided in the main text, where two alternative techniques are described for setting lens tilt for medium/fardistance working and close-up. In the appendices, there are tables and notes on their creation, showing how just one distance measurement enables initial setting of tilt for placing the plane of focus at a known position with a tilted lens of a particular focal length.

WHAT DOES SHIFT DO?

There are descriptions of many lenses and adapters offering shift functions in Chapter 2, along with much more detailed coverage on the practicalities of shift in Chapter 3, but the basics are easy to show. If you point a level camera at a building, the vertical sides will be straight, but point the camera upwards and vertical lines will converge. The convergence is more noticeable the wider the field of view. Using a shift lens with the camera level and the lens shifted upwards 'fixes' the problem with converging verticals. It is for this reason that tilt/shift lenses are sometimes known as 'perspective control' lenses.

In itself, there is nothing wrong with the strongly angled composition, but the author's experience as an architectural photographer suggests that most clients will be far happier with non-leaning verticals. This difference should not be assumed to mean that one composition is better than another, just that, as a working photographer, it pays to know what your clients expect. The strongly convergent shot can be a deliberate creative choice, whilst a slight convergence that could have been corrected with just a few millimetres of shift can, to some, look careless.

WHAT DOES TILT DO?

Shift is relatively easy to explain. Showing the difference between a shifted and non-shifted view of a building makes it quite clear. Tilting the lens moves where the plane of focus is positioned in front of the camera and subtle uses of tilt may be quite difficult to spot in an image without knowing what to look for. Combining strong tilt and wide aperture, with its limited depth of field, can give unusual combinations of blurring and sharpness, sometimes resulting in a 'miniature-world' look to images.

Tilting a camera upwards produces characteristic convergence of vertical lines. The wider the lens, the more apparent this tends to be. Whilst not 'wrong' in any way the strong lean may not give the style of image required.

Using a lens shifted upwards eliminates the converging verticals. A longer focal length (35mm vs 15mm) also gives a better sense of scale to the image. Using shift is often appropriate for correcting small amounts of convergence of verticals.

Effective use of tilt requires the setting of both the lens tilt and the lens focus. It is this combination of settings that often causes confusion, especially since the lens-focus setting now moves the plane of focus around in a somewhat different way to how it moves back and forth when focusing a normal camera lens. Add to this any unfamiliarity with manually focusing cameras, and it is no wonder that many photographers give up on the more precise and subtle benefits that using lens tilt can offer.

By using a wide aperture (f/2.8), a tilted lens (Canon TS-E90mm F2.8L Macro) and a downwards-looking viewpoint, the narrow plane of focus cuts through the scene, giving an image that many may perceive as a photograph of a model. The tilt axis of the lens is horizontal, with the lens tilted downwards by several degrees.

Turning the tilt axis to vertical gives a plane of focus that cuts through the scene as a vertical slice. The lens is a 210mm medium-format lens used with a tilt/shift adapter on a Canon EOS RP mirrorless camera. The lens is tilted by nearly 10 degrees to the left, with the plane of sharpness placed to run along the edge of the path.

Looking along an equipment rack in a narrow underground area, where there is limited space. The photo is taken using a wide-angle 17mm lens. At f/10 the depth of field is significant, but the far panel is slightly blurred.

Tilting the lens (a Canon TS-E17mm F4L) to the right places the plane of focus along the instrument panels and intersects the panels at the far end of the rack. A careful comparison also reveals the slight change in image geometry from the movement of the lens when tilted.

Running the plane of focus along a wall (or floor or ceiling) is a simple task once the relationship between tilt and focus is grasped. Whilst the miniature-world look is the effect of lens tilt being emphasized, many uses of tilt only become apparent when looking at an image and taking time to wonder just how the photographer managed such a huge apparent depth of field. Tilt doesn't give more depth of field, it just allows control of where the available depth of field is placed.

WORKING MANUALLY - CAMERA ISSUES

One of the difficulties many face with tilt/shift lenses is unfamiliarity with manually adjusting camera settings. Depending on the camera, using a lens with tilt and/or shift can throw off metering and even focus confirmation. This happens since cameras are designed for normal non-shifted and non-tilted lenses. Once the lens is tilted or shifted, the light rays coming in from the lens no longer enter the camera at the expected angle. The changed light angles can very occasionally cause some colour/exposure variation across the frame, but this varies by camera model and lens choice. It is not generally a problem with camera makers' own tilt/shift lenses, but is worth investigating when using lens/camera adapters.

Comparing magnified portions of the distant parts of the image shows the improved sharpness in the tilted version, where the tilted plane of focus runs.

From the same two images, magnified sections of the panel just a short distance from the camera show similar levels of sharpness.

Lest it be thought that having to work manually is a hindrance, there are many who would say that mastering the skills needed for manual working can only benefit most photographers, giving a far more intuitive understanding of focus and exposure, even when subsequently using camera auto-focus and auto-exposure modes. Similarly, one of the author's motivations for trying to explain more about using tilt/shift lenses is that much like printing photos, once mastered, it benefits all of a photographer's work.

DSLR issues

The camera-exposure metering for DSLR (Digital Single Lens Reflex) cameras is usually measured at some point after incoming light is reflected off the reflex mirror, up in the top of the camera where the pentaprism or mirrors reside. The change of light angle with shift and tilt can cause under- and over-exposure depending on the movement of the lens. If using camera metering, check exposure with the lens in an unshifted and...