Article - Technical Tip

Making Buildings Stand Up Straight

You will have noticed that when we photograph buildings from up close they have a tendency to look as if they are sloping backwards and perspectives can get corrupted.

The result is that the image slopes in at the top, is shorter, and with angle shots may give weird views and impressions.

There is a technology based way to achieve this in some cases, that has been around for decades and used by generations of 35mm photographers, and this is with a perspective control lens. Early ones took a simple approach of a lens with greater coverage that just slid upwards in a mount some however became more complex using both a sliding and a wedge that tilted the lens up.  PC lenses standing for a Perspective Control lens, also known as tilt and shift lenses or when they only slide, a shift lens, the shift is the sliding upwards and the tilt is in effect the bending of the lens. There were, some time ago, a range of Nikon manual focus PC lenses, that achieved this, that developed over the years, but they have not been produced for some time. More recently we had the option of a 85mm macro lens that had a perspective control to allow the lens to focus over a larger distance range, although this has recently disappeared from the UK Nikon website, it can still be found on the global site.

The tilt and shift is limited to a smaller amount with all except the D3, and an electronic aperture feature works with only the D3 and D300. This lens has a button stopping it down, similar to a normal lens when you have the depth of field button pressed, and remains like this until pressed again. Shift and tilt movement are at right angles. The two operations can be modified for a surcharge, to move in the same [parallel] direction. The shift lock release knob can also be changed for a larger one, but the changed knob may affect mounting the lens to the camera or lens operation. It is manual focus.  Two more PC lenses will be available also soon the PC-E Nikkor 45mm f2.8D ED, and PC-E micro Nikkor 85mm F2.8D. We don’t have details of these yet.

Older Nikon shift lenses can be purchased from eBay and elsewhere and you will find one from around £150, however as most are at  35mm, with a few at 28mm, they are not as wide as the new 24mm. They vary by area, features and maximum aperture. You can also use a shift lens sideways to take panoramas that are somewhat simpler than using a panorama head, although limited in width.

In some software, for example Photoshop CS3 and Elements, you have the ability to stretch the image afterwards both pulling out the upper parts and making the image taller. This means that you can take the photograph as you normally would and make changes later.

In the two examples above we have used Photoshop Elements to correct the perspective in part, and normally this would be done before sectioning, in this case we have left the image unsectioned so you can see the effect that has taken place.

However this is not always as simple as it sounds especially when other items are in the photograph and are further away. So you may find you need to cut out the building, and deal with the perspective of this separately, from some or all of the background. This is often achieved best when slightly under done so you have a very slight tapering, and you have to avoid going too far and making it look completely unnatural. This does not overcome the problem of depth of field as the distance to the top of the building is always far more than from the base, however the depth of field with wide angle lenses is large so you should be able to focus so as to get the entire building in focus.