On a recent photography holiday I led for HF Holidays, we discussed converging verticals and how to fix them. Converging verticals happen when you are at ground level close to the base of building and use a wide-angle lens to get the whole building in.
This example, of the Musuem of the Gorge in Ironbridge, Shropshire, shows what happens. I used an 18mm wide-angle lens, stood close to the base of the building, and pointed the camera up. I was closer to the base of the building than the top, so the base looks bigger and the top looks smaller. This has the effect of making the sides of the building, which should be vertical, appear to converge at a point outside of the frame. The building seems to be leaning backwards.
So how do you fix this? Well, there are various methods:
You can use a longer focal length lens and get further away from your subject. This means that the distance from you to the base of the building and you to the top of the building are more equal.
You can also try and get higher up, again to equalise the distance between you and the top and bottom of the building.
You could use a special lens called a “shift lens”. These are very expensive and uncommon, so are not really a practical option for most photographers.
You can correct the perspective distortion in Photoshop. You do need to leave plenty of space round your subject to allow for the cropping.
In this second image I have moved further away, used a 36mm lens, and got higher up. The sides of the building are now parallel with the image sides and it looks much more natural.
You could, of course, not worry about such things at all and just use the converging verticals to emphasise the size of the building. This castle tower in Clun is an example. The convergence makes it look much bigger than it does in real-life (whatever that is!).