Learning How To Use a Tilt-shift Lens
- Timothy Basham
- Jul 21, 2024
- 7 min read
Updated: Apr 15
What’s that?
More correctly called a perspective control lens, it can tilt the lens plane backwards or forwards relative to the camera’s film (sensor) plane or shift the lens up or down (and/or left and right) parallel to the film plane.
But how can it do that without leaving blank areas on the image?
The image produced by a lens is round, not rectangular and, appropriately enough, is called an image circle. However, provided that the camera’s sensor fits fully within this circle, the resulting image will cover the entire frame and be free of vignetting.
To put this in context, although a ‘normal’ lens covers the sensor that it was designed for in its entirety, a crop sensor lens on a full frame camera could, particularly at wider angles, vignette or even show the image circle. A Nikon D610/Nikkor 18-55mm DX lens combination, for example, starts vignetting at around 35mm and the image circle is clearly visible at 18mm2.
Conversely, a full frame lens on a crop sensor would produce an image circle large enough to cover the sensor with some to spare. It is this principle that allows tilt-shift lenses to work as they are designed not only to have a larger than necessary image circle, but to have all the necessary knobs and dials to access these areas.
So why would you need one?
Apart from these lenses functioning perfectly normally in their non-tilt, non-shift position (minus the ability to autofocus), they can enhance both technical and creative aspects of a photograph.
Shift Function
Correct Perspective
Primarily a perspective control lens excels at, unsurprisingly, correcting perspective. The shift function eliminates converging verticals by shifting the lens to accommodate the image without the need to tilt the camera upwards (or downwards) therefore eliminating perspective and vanishing points.
Formal architectural photography is the most obvious genre to benefit from this function. In situations where it is important that buildings are shown straight and upright to celebrate the architect’s creation, rather than the photographer’s artistic vision, the ability to make corrections in camera are a key feature of the tilt-shift lens.
It is also suggested that perspective correction can be used in nature too and, although examples on the internet of converging verticals being corrected on single trees are questionable, (after all, a tree is thinner at the top anyway), it definitely can help prevent groups of trees looking as if they are all converging at the top.
Corrected Perspectives
Panoramas
Digital photography and ever more sophisticated post processing software makes it easy to stitch multiple images together. The usual way of creating these panoramas is to mount the camera on a tripod and pivot it along the horizontal plane, ensuring that each image overlaps with the last. With a tilt-shift lens, the panorama is generated by moving the lens across its full range of movement. Because the film plane is not moving during this process in relation to the subject, the stitching process will match pixel for pixel at the join creating a more natural final photograph. The first method may display an amount of distortion in the final image, especially where wide angle lenses have been used.
Two Panoramas
Tilt
The key feature of the tilt function is the greater level of control it gives over depth of field. It doesn’t replace the function of the aperture, rather they combine to give more precision and flexibility.
Still Life
With still life, or product photography, it can be difficult to get front to back focus, regardless of the aperture used. With digital photography, it is possible to take multiple photographs with different points of focus and get Photoshop to merge the images together (focus stacking). With the tilt-function, it is possible to achieve this in camera by widening the depth of field beyond that achieved using the aperture ring alone by taking advantage of the Scheimpflug Principle.
The Scheimpflug Principle describes the effect of the plane of focus in a situation when a lens is not parallel to the film plane. Formulae, which I have only seen the like of since trigonometry lessons 35 years ago, help calculate all the angles necessary for the film plane, subject plane and lens plane all to intersect together. Although I used rough swinging of arms as a substitute to these calculations, by tilting the lens according to these principles, the plane of focus is extended and all items in the subject plane will be in focus.
In Principle
Miniature effect
The miniature affect, uses Captain Scheimpflug’s principle against him. By tilting the lens away from the intersect point with the focal and subject plane, the depth of field narrows creating a thin strip of focus which can render subjects as if they were miniature. For the best effects, it is important to get some height above the subject.
Toy Town
Other uses
The principles above can be applied to any number of situations from extending foreground to infinity sharpness in landscapes, or adding interest to portraits by being more selective with areas in focus.
Two Portraits
This is the digital age. Can’t a computer do that?
Yes, arguably, with ever more powerful post-processing tools, it isn’t necessary to achieve these effects with specialist equipment . Straightening verticals can be done in seconds in Lightroom and even Instagram has a tilt-shift filter.
That said, arguably, it is better to get the image right in camera. An article by Adobe3, who know a thing or two about post processing digital images, underline this very thing citing the potential loss of image quality the more ‘work’ software has to do with correcting perspective, leading to cropping, loss of information and potentially changes in composition.
Was it worth it?
Ultimately, there is no right or wrong method here. Everyone is free to choose how they photograph and subsequently process their images. There is no agenda here.
This was an exploration of technology and how it works and I am 100% sold on the shift function for both perspective correction and panoramic work.
The tilt function will take longer to master and I would like to try other focal lengths. This is the start of a journey which may be quicker through technology, but will certainly give me a better understanding of how lenses and depth of field works.
Example images are taken with a Nikon D610 with PC-E Nikkor 24mm f3.5 lens.
Full frame cameras will generally automatically adjust and account for the useable sensor when a crop lens is used. It is possible however to turn this feature off. ↩︎
Nick Ulivieri & Andrew Pielage, [no date] Tilt-shift photography | Complete beginner’s guide | Adobe [Accessed 11th July 2024] ↩︎
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