Diagonal lens shift
Diagonal lens shift
Combining horizontal and vertical lens shift
Shift lenses are widely used for correction of converging verticals in landscape and architectural photography.
Horizontal shift is popular for stitching images and moving the camera’s reflection out of a shot.
Less well understood is that you can combine the two movements. In this short article, Keith Cooper shows some examples of diagonally shifting the lens.
Tilt/shift article/review index page
Covers all of Keith’s 50+ articles.
If you’re new to shift lenses, then my article about how to use lens shift may be a better starting point. It covers the basic operations of using a tilt/shift lens for shift.
There are two adjustments/settings most commonly used with shift lenses. Up/down and left/right are the basic functions, usually achieved by rotating the lens body relative to its mount.
Note that vertical shift is often called rise or fall whilst left/right movement is just called shift. In my articles I refer to any lens shift movement as shift, along with the direction the lens is shifted.
The examples above are with a Mamiya 35mm M645 medium format lens used on an EOS RP with a Fotodiox tilt/shift adapter. The large amount of shift makes the direction more obvious than if I’d used one of my TS-E lenses.
This first shot shows the square on view of a white building I want to photograph. Since I’m square on to it and the camera is level, there is no convergence of horizontal or vertical lines.
Unfortunately, most of the building is missing.
If I tilt the camera upwards I’ll get it in, but then the verticals will converge.
So, I add vertical shift and it’s all in the shot.
The problem is that I don’t want so much of the brown building in the shot.
I could pan the camera to the right, but then the horizontal lines of the building would converge. This is similar to the vertical convergence I noted earlier, but is generally less noticeable – it’s there in the horizontal lines of the brown building.
I need to shift the lens to the right, but it’s already shifted upwards. Fortunately I can combine upwards and leftwards shift by shifting diagonally. A simple rotation of the lens mount achieves this.
The white building is now better placed in the frame and I have the path and space beyond to give a better sense of depth and context for the building.
The direction of shift and amount are trickier to estimate than simple movements, but not difficult to master.
If you look at the top right corner of the image above you can see the sky is just a bit darker than expected. This is normal lens vignetting, but by using diagonal shifting we’ve exacerbated it in the corner we’re shifting into. Not really an issue in a photo like this, but if there was important detail in the corner, it would be in a poorer part of the lens image circle. A small aperture (f/11-16) will help, but shifts like this will certainly show up deficiencies in some lenses.
This shot used the 2007 Canon TS-E24mm F3.5L II lens – had I used the 1991 mk1 version, that darkening would be very much more obvious.
For the stitching
I’ll often stitch two shots vertically shifted, to get a higher resolution squarer image.
There is of course, no reason not to stitch diagonally shifted images.
With the lack of suitable click-stops in the rotation mechanism of some lenses, it can be physically a bit more difficult to set up. However, a lens mount such as the TSE Frame helps and I’ve stitched four images quite easily.
Changing the viewpoint
With a level camera and normal lens, there is a natural viewpoint to an image, shown by taking a line orthogonal to the sensor, out through the centre of the lens and going through the scene in front of you. In normal use, this line is equivalent to the centre of the photo.
Shift a lens and this centre point is offset (the opposite direction) in your photo. One way to think of this point is, where you are pointing the camera.
Normally, with a bit of vertical shift we don’t notice this aspect very much, but with horizontal shift it becomes a bit more obvious, especially with wider lenses. See the basic using shift article for more – it has some video clips showing the shift action.
With diagonal shift we get even more control over where to place this viewpoint. In the example below I’m pointing the camera down the walk way, even though most of the building I want to show is upwards and off to the left.
You can easily use this effect to balance the foreground and way the viewer’s eye is led through the image.
I prefer it to the vertical only shifted version, where the sloping ground level and the strong diagonal in the top right unsettle things more than I want (YMMV!)
Use with wide lenses
A wide angle lens (rectilinear, not fisheye) can easily give a feel of stretching the corners out. This is particularly noticeable if there are people in the photo. It’s a natural consequence of a wide rectilinear view.
With a non shifted lens, this ‘distortion’ is symmetrical about the centre of the image. Add shift and not only is the viewpoint moved, but the degree of stretch can be changed.
Take these three views of the same scene. The first is simply using a bit of vertical shift with the TS-E17mm lens.
Moving closer, diagonal shift breaks the simple symmetry of the path, but the closer part of the building is now very prominent.
Switching to a 24mm lens gets a more balanced view (from further back). The diagonal shift has allowed me to still move the path away from the midline of the photo.
Use with care
Diagonal shift gives me more control over the composition when using shift.
My main use is to break overly strong centre symmetries. It’s something I don’t use that often since it can be a bit fiddly to set up, and I’ll tend to avoid the views needing it. That said, it can make quite a difference, if you remember that it’s an option.
Never miss a new article or review - Sign up for our occasional (ad-free) Newsletter
Enjoyed this article?
All the latest articles/reviews and photo news items appear on Keith's Photo blog
We've a whole section of the site devoted to Digital Black and White photography and printing. It covers all of Keith's specialist articles and reviews.
For All about using tilt and shift - articles/reviews about tilt/shift lenses
Articles below by Keith (Google's picks for matching this page)