DARK PHOTOGRAPHY

Photography:

Successful photography underground is notoriously difficult and can often prove troublesome to the un-prepared. I hope this brief guide on how to properly prepare your camera and equipment will help you understand the problems and help you to overcome the common most mistakes that occur whilst trying to capture the perfect underground scene.

Knowledge of your camera's controls are probably the single most important area that you should learn. Most cameras, from a simple compact with basic controls to a full-on DSLR should allow you some degree of control to the way that the image is captured. Because of the unusual conditions of mine photography and the vast range of cameras available, I will concentrate this guide to the use of a mid-range compact camera with the common "M.A.S.P" or "Manual", "Aperture", "Shutter" and "Program" functions (which will cover all DSLR's). If your camera does not have the required setting controls then you can still follow this text but apply the same principals to your imaging technique.

This list is not definitive, but you will certainly need the following equipment:

1. A reasonable digital camera of at least 2mp, ideally greater than 5mp for that extra detail with full M.A.S.P control.

2. Tripod. Trying to take decent a photo in the dark is nearly impossible without a tripod.

3. Good quality torch or slave flash unit (or both!)

4. Ideally a cable release to fire the shutter, but most cameras offer a self timer in the feature set.

To capture fabulous underground shots nearly every time, you will require:

5. A long range, high output Luxeon LED torch (minimum of 3 watts).

6. Independent Slave Flash (or more than one) that is triggered by IR.

Taking a clear photo in the dark is quite problematic at the best of times, but when you try to capture an image in an enclosed, humid underground space the problems will increase ten fold!

To carry a tripod through the underground passages in a 100 year old disused mine would seem excessive for an armature photographer, but the tripod is almost as important to obtaining a clear, colorful photo as the camera its-self. In mines or underground caves, dark.. really is y REALLY dark!! This darkness requires some special equipment to illuminate sufficiently to obtain a proper photo as well as some well chosen camera settings.

Haze or Mist

Most people would think that you will absolutely need the camera's flash to fire in order capture anything at all in the dark. But by firing the inbuilt camera flash you will most likely capture a giant white cloud of moisture or dust ('orbs' as "most haunted" fans would misguidedly think!)

The captured moisture cloud on the left photo is caused because the mine floor is wet, and the air is very still. If any moisture is present - be it either general wetness as in the photos above, or a running waterfall - then the procedure below should help in obtaining a good picture:

1. The mist is generally caused by light bouncing off the partials of moisture in the air and reflecting back into the camera lens. The key is to not use the camera mounted or inbuilt flash unit.

2. Set your camera to 'M' or 'Manual' mode (or 'P' if pre-sets are used - see later) and use the following settings: Shutter speed (S) should be set in the range of 15 seconds to 30 seconds depending on the lightness of the tunnel. Aperture (F) should be as small as possible (bigger F.number) to help obtain a clearer focused shot - though most likely in the pitch darkness, the maximum you can probably use is F5.0 without using the cameras 'BULB' (infinite shutter speed) setting.

3. It is most essential to use a tripod and set the camera to self timer to take the shot. (if using an SLR, use the 'MUP' or 'Mirror Up' setting). Whilst standing to one side of the camera, once you hear the shutter release shine a torch around the entire scene, concentrating the light on an area of interest or into the distance to obtain a long distance shot. 

4. Examine the photo on the cameras screen and adjust either the aperture (f number) or shutter speed (S) to brighten or darken the shot. The higher the 'F' number, the darker but sharper the scene. Lowering the shutter speed will reduce the risk of camera movement or subject movement as well as reduce the camera noise caused by using a small aperture. (Note that camera noise is also caused by a higher ISO value, see below)

The photo above right was taken using an aperture of just F3.5 but at 25 seconds exposure or (S) Shutter speed.

Focusing problems

Obtaining correct subject focus is a massive problem with a camera in darkness. When using a digital camera the internal software requires that the lens can focus on a suitable area within the frame in order to produce a useable photograph. However, whilst underground it may prove difficult or impossible to provide enough lighting to a subject to allow the camera to perform its auto-focus procedure.

Most cameras have a manual focus setting that allows the photographer to visually set the focus ring to the correct position to obtain a clear shot of the subject. But a problem will immediately appear in that the photographer will not be able to see anything other than darkness through the view finder or screen. So, forward planning is required by using the steps below:

1. Before entering the dark cavern, and whilst standing in the light of day - try to calibrate your self to your cameras focus settings/ring. Stand looking at a subject that is maybe four to six feet from your cameras lens and manually focus your camera whilst taking great care to 'feel' the amount of rotation that the focus ring requires before the subject is brought into full clarity. Take into consideration the zoom or focal length that you are using and make certain to leave this setting alone when using this method!

Remember that when you obtain a solid focus, two thirds the distance behind the subject will be in good focus and one third in front should be as well - with this in mind a nearer object is better to set your focus than a further one.

2. Enter the tunnels and find something interesting to photograph. Here comes the difficult part: Turn off your flash and ready your torch. Set the camera to manual focus (auto focus will not likely work properly). Set the focal length to whatever you used outside (the zoom), then turn the focus ring or setting to the same amount that you experimented with in the daylight to obtain a sharp focus. 

It is easier said than done, but mostly I find that on my alpha100 the focus ring requires a tiny movement clockwise from fully anti-clockwise! Using a dab of tip-ex on the lens body and the focus ring will assist in setting the correct focus.

3. Stand back, set the camera to 'MUP' or 2sec (or 10sec) and stand well away. As the above method, be sure to highlight the entire tunnel to obtain a workable photo.

I have found that a small drop of tip-ex on the focus ring is an excellent way of gauging the position of focus. Typically at a small focal length - a tiny adjustment is all that is necessary to obtain a clear photo.