> Techniques > Recording > Photographing Objects
- Recording Objects on Site
- Photographing Objects on Site
- Recording Finds
Techniques: Photographing Objects on Site
If you find something interesting during a seabed search then it is important to be able to record some basic information about what you have found. A quick and easy method of recording an object on the site is to take photographs of it. If a scale is included in each photo then it is also possible to take measurements of the object from the photographs or to make a simple drawing of the object.
Method
A photograph of a newly found object can help when asking other people to help identify it. The kind of photographs you can take depend on the object itself and the underwater conditions but in essence you need two types of photographs, some that show the whole object and some that record particular details. A typical set of photographs includes one of each side of the object, one from above and ones from the corners looking down. The photographs taken of each corner are called oblique views, the taken straight on to the sides and ends are called elevation views and the photograph from above is called the plan view.
The camera should be close to the object and if possible the object should fill nearly the whole picture, this reduces the amount of water between the camera and the object and makes the details as sharp as possible.
A scale must be included in all photographs to give an idea of the size of the object. This should be a proper photographic scale but a plastic folding rule can be used or even a piece of your diving equipment or your buddy’s hand if nothing else is available.
Oblique Views
Oblique views are often the most useful as they show the general shape of the object.
- Take four photographs around the object with the camera pointing down at an angle of 45°, this is half way between horizontal and vertically downwards.
- Try and keep the camera as level as possible.
- Place the scale and a North arrow if you have one on top of the object as this will help identify which way round the object is in each picture.
Here are the four oblique views around the same object:
Oblique view photographs are useful for helping understand the shape of an object, but it is often difficult to take measurements from photographs taken at an angle.
Elevation or Side View
To take measurements from photographs then it is better to have the images sideways on to the object. If the scale bar is also sideways on to the camera then measurements can be taken from the photograph and scaled using the scale bar into real distances in metres.
- Take four photographs around the object with the camera pointing horizontally
- Try and keep the camera as level as possible
- Place the scale in front of the object and as close to it as possible
Here are the four elevation views of the same object:
Plan View
Being underwater it is possible to float above the object and take a photograph straight down, this is called the plan view. This view is very useful as it can be used to create a detailed scaled plan drawing of the object that can then be added to the main site plan drawing.
- Take one photograph directly over the object with the camera pointing vertically downwards
- Try and keep the camera as level as possible
- Place the scale on top of the object or on the seabed close to the object
Detail Views
Detail views are used to record any significant features on the object, these may be used to help identify it, to capture a record of the object or to add detail to a drawing of the object.
- Take one or more photos of each feature on the object
- Take the photos from slightly different angles as some will show up the detail better than the others.
- Make sure that the scale is visible in each photo, ask your dive buddy to hold the scale if necessary
Large Objects
If the object is too large to fit into one photograph then it can be recorded in a series of overlapping photos that can be joined together later on using image processing software
Equipment List
- Underwater camera - Compact digital camera with an underwater housing
- Photo scales - 1m and 500mm long photo scale bars, scale card, folding rule
- North arrow - Plastic square marked with a north arrow