Night Photography - Film Introduction Locomotive images taken at night using my simple method, can produce results of publishable quality, that does not require the investment of expensive and sophisticated camera equipment. A relatively cheap manual SLR camera with a standard 50mm lens can often produce better results in the hands of a relatively experienced night photographer, than a novice equipped with an expensive state of the model.
Film Selection I strongly recommend that beginners master the technique of night photography using colour print film as there is a much greater latitude for exposure error than with the transparency film. With transparency film its either correctly or incorrectly exposed. Generally speaking 100asa rated film is a good compromise between doubling the exposure time using 50asa rated film, which produces marginally sharper images and 200asa rated film, in which the exposure time is halved, although the sharpness of the image is compromised.
Equipment The following set up of equipment is strongly recommended to ensure of consistent quality:-
Equipment Set Up Mount the camera on the tripod and attach the cable release and spirit level. Spend time in composing the picture, using the spirit level to ensure verticality.
Focusing For ease of operation set the lens to manual operation if it's automatic, and set the object distance to infinity. The rationale for this is that the distance from the camera to the locomotive will always be greater than the hyperfocal distance of the lens. The hyperfocal distance of the lens is the nearest point from it that will be in focus and is calculated by dividing the focal length of the lens by the aperture setting number. For example, the hyperfocal distance of a lens of focal length 50mm and an aperture setting of F5.6 is nearly ten metres.
Exposure Control For a given film rating and lighting conditions, the amount of light that is required to correctly expose the film is directly related to both the aperture setting number and the shutter speed. The aperture setting number is a constant, which relates the size of the opening of the diaphragm, to the focal length of the lens. the higher the value of the aperture setting number, the smaller the opening size of the diaphragm. The shutter speed is the time duration in which the diaphragm is open. So, for a specific lighting condition, there is a multitude of combinations of aperture setting number and shutter speeds to produce the same exposure. Some cameras with automatic exposure control work fairly accurately under low lighting conditions but for optimal performance manual operation is strongly recommended.
Aperture Setting The depth of field, the distance between the nearest and furthest point from the lens that is in focus varies with both the focal length of the lens and the aperture setting number. The depth of field is inversely proportional to the focal length of the lens and proportional to the increasing magnitude of the aperture setting number. Setting the aperture to F5.6 as described in the focusing section will produce sharp images and maximise the shutter speed thereby minimising the opportunity for spoilt images.
Shutter Speed ( Bracketing ) With the aperture setting number set to F5.6, we must now bracket the shutter speed in order to establish the correct exposure. Bracketing is an experimental method of taking a series of images with varying shutter speeds, whilst keeping the aperture setting number constant, in order to produce an image of the correct exposure. A good starting point on a fairly well lit platform is 4 secs exposure, which we will define as our nominal shutter speed. Take the picture at this nominal lens setting of 4s / F5.6 and record this information into a log book with the frame number. Take a further four images at 1/2 stop increments both below and above the nominal shutter speed and similarly record this information in to the log book whilst keeping the aperture setting number F5.6 constant. The series of shutter speeds used, in decreasing order of shutter speed, should equate to 16secs, 12secs, 8secs, 4secs, 2secs, 1 1/2secs and 1sec.
Developing The Film Once the roll of film has been used, take it to a local photographic laboratory for developing and printing and explain to the technician that the images have been taken at night and are bracketed. This will ensure that the Laboratory do not compensate for over and under exposure when printing. Reviewing The Images Once the prints or transparencies have been received from the photographic laboratory, take a deep breathe and carefully lay out the prints or transparencies in identical order that you have taken them and record on to the rear of each print or the front of each transparency, the film rating, aperture number and shutter speed settings from the details that you have recorded into the log book. You should now, from the selection of images, be able to select the optimum exposure and use this as a bench mark for the future. Railway magazines are full of images taken at night and generally speaking for maximum impact, they are presented slightly over exposed.
Maintaining An Exposure Setting Register It is very wise in the early stages of mastering the technique of taking pictures at night to maintain a register of the optimum exposure settings for each location, from the results that you have received and after a short period of time, you ought to be able to get a good gut feel within + or - 1/2 stop of the correct exposure setting for each location. The correct exposure setting is very personal and subjective, at what looks right to you may not be the same view someone else may have. |
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