Through the looking glass

Using the correct lens is critical to Urbex photography success.

The size, f-number and even the weight of the lens you use will determine your image’s forces and weaknesses. It will induce the image’s distortion, saturation, depth of field, bokeh and, dare I say it ? Probably its soul, no less !!

Before I am burned at the stake for heresy, let me explain…

A lens is a transmissive optical device, that focuses or disperses a light beam by means of refraction. The word lens comes from lēns (legume familly), the Latin name for a “lentil”; because a double-convex lens is lentil-shaped.

The lens (or glass) you’ll use will determine the image you’ll get. It will produce a real figure, that can be captured on photographic film or an optical sensor.

Many factors will come into play, but the most important just might be your lens’s brightness, the dread f-number, which contrarly to popular belief, does not stand for fuck-number.

The f-number of a camera lens, is the ratio of the focal length to the diameter of the entrance pupil. It is a dimensionless number that is a quantitative measure of lens speed, and an important concept in photography. It is also known as the focal ratio, f-ratio, or f-stop. It is the reciprocal of the relative aperture. The f-number is commonly indicated using a hooked f with the format f/N, where N is the f-number. To relate to human kind (which I imagine you are part of…) the f-number of the human eye varies from about f/8.3 in a very brightly lit place to about f/2.1 in the dark.

Whatever focal length you choose, you should always prefer bright glasses in Urbex situation. As we said, the closer that number to 0, the more light will come in.

For Urbex I recommend minimally f/2.8, but frankly f1/.4 is better !!

Bright lenses will allow you to work with shallow depth of field, but more importantly, will allow in vast quantities of light when the conditions are less then ideal. Depth of field increases with f-number. This means that photographs taken with a low f-number (large aperture) will tend to have subjects at one distance in focus, with the rest of the image (nearer and farther elements) out of focus. This will allow you to forgo a tripod, as much as possible. Focal lenght will also have a noticable impact on your picture. A 30 mm, will not give you the same picture as a 200 mm, even if croped to look alike. The depth of field and the distortion will be completly different.

Beware though, most very bright lenses do not offer their best when totally open. Tack sharp images usually happen f/3-4 stops above maximum aperture. It will then range between f/5.6 and f/11.

When carrying a DSLR in Urbex situation (which, full disclosure, happens less and less), my lenses of choice are usually a 35 mm fixed, a 12-24mm and and 75-200mm. Since my DSLR is an APS-C, that would be the equivalent of a 50mm, a 18-25mm and a 100-300mm.

Keep in mind that on APS-C and lower end cameras, you must take into account a lens multiplying factor. 1.5 X for Nikon, 2 for Olympus and Panasonic 4-3rds, and 1.6 for Canon. That means that your Canon 10-22mm is the equivalent of a 16-35mm.

• Fixed focal lens with very high aperture are great. They are simple, solid and allow you to focus on details and textures.
• Ultra Wide Angle are probably my lenses of choice in Urbex. It allows for great global shots, without much space to take them. They accentuate perspective while making image composition very dynamic. The issues you will face mostly is distortion, which can somewhat be corrected in post treatment. But it helps if you keep it in mind while shooting: When taking your picture, look into the view finder a go from top to bottom; you will most probably find a sweet spot, where distortion is less present. If you can have a straight reference in your image, (a straight pole for example), your post treatment will be greatly simplified.
• Fisheyes are the widest of all lenses. I am not a fan given they’re incredible distortion levels. Don’t get me wrong; they are sublime for large spaces, but require too much things to happen. A half empty scene will loose all interests when shot with a fish eye; it will be completely unreadable. In my book, fisheyes are more of a graphic tool then a photographic tool per se.

Always keep in mind that Urbex is usually carried out in rather dusty conditions. That means changing lens can be quiet hazardous to your gear. So I recommend practicing changing your glass as quickly as possible, with your camera body always facing the floor.

If the proverbial shit hits the proverbial fan, and dust nevertheless finds a way to your sensor, you will see tiny specs on your finished pictures. A few things can be done to limit this…

1) Clean your sensor at least once a month, using an ad-hoc kit.

2) Use the camera’s sensor cleaner. This feature can usually be used overtime you turn your camera on.

3) Clean the dust spots during post production.