Using a Digital SLR Camera on a Paranormal Investigation

I have been using a Canon PowerShot S50 when doing investigations or just having a good ol' time ghost hunting. The camera itself is a great camera, and even though it's 6 years old, I still think it takes better pictures than most of the newer cameras. 

Recently, I decided to buy a digital SLR camera. The main reason for doing this was so I can take picture of the city at night as well as having complete control over the camera's operations.

Sensor

First, looking at the sensor of a DSLR. There are three main sizes:

  1. Full Frame: The sensor is the same size as 35mm frame. With a sensor that size, this makes the camera much more expensive. One upside to this is that you get a larger angle and it's easier to get shallow field depth of field effects.
  2. APS-C: Most common among the DSLR cameras. The smaller sized sensor chip makes it so that the object you are taking a picture of appear closer. With APS-C, you end up only capturing about 2/3s of what a Full Frame sensor can capture. This is not necessarily a bad thing because the effect that the smaller sensor produces is called the crop factor. This helps telephoto lens as it makes them appear more powerful. This sensor size is most common and in order to get a true wide angle view, special lenses will have to be purchased.
  3. Four Thirds (4:3): has a crop factor of two, which means you are only seeing half of what a full frame sees.

The other aspect of the sensor is the sensor type, is it a CCD or CMOS? In my Canon PowerShot S50, I have a CCD sensor, which stands for Charge Couple Device. Comparing it to other cameras at the time and some new models I noticed that the images were more crisper opposed to the CMOS, which was a bit more grainy. To get an idea of the difference in sensors, think of a sensor as a collection of solar cells collecting light. Each cell accumulates a charge proportional to the location of the light source. Neither is better than the other one. Both have their strengths and weaknesses.

  • Charge Coupled Device (CCD) - The cells capture the light charge and transfers it across the sensor where the charge is converted to voltage, buffered, and sent off-chip as an analog signal. Since the voltage is sent else where for processing, there is more room for the cell to be larger, therefore it's able to capture more light and better pictures. Since the charge is off loaded from the sensor and processed else where, CCD cameras tend to use more power than CMOS cameras.
  • Complementary Metal Oxide Semiconductor (CMOS) - The main difference with CMOS opposed to CCD is that each pixel has it's own transistor for amplifying and moving the charge off the sensor. In addition to this, each pixel has it's own lane which means that each pixel can be read individually. Because each pixel has it's own transistor, it can do the work on the sensor opposed to a CCD which moves the charge off the sensor, this increases the speed of the image. However, because CMOS sensors are used in more consumer grade electronics early on, the advancement of this feature is behind. A unique feature of CMOS sensors is called Windowing. Windowing is the ability to read out a portion of the image sensor. CMOS sensors consume less power than CCD sensors, but CMOS sensors suffer from more noise because of the transistors next to the cell. Also, because a CMOS sensor has a transistor next to the chip, there is more space where another cell could be placed to capture more light. Although both sensors perform antiblooming -- ability to gracefully drain localized overexposure; CCD sensors require specific engineering to prevent localized exposure where as a CMOS sensor has natural blooming immunity.

In terms of reliability, both types of cameras offer equal reliability in consumer and industrial applications. It's when a CMOS sensor is placed in a device that is used in an ultra rugged environment; that's when its reliability shines. This is because all of the functions are placed on the CMOS sensor which minimizes failure points such as solder joints.

I went with the CMOS based Nikon D5000 because it was cheaper, it offers antiblooming, windowing, and has all the functionality on the sensor which decreases the chance of the charge being disrupted when being moved from the sensor and converted on a separate board. One thing that I hear with the standard party cams (like my PowerShot) is that 'more mega pixels means it's a better camera.' Not really. More mega pixels just means the image can be blown up with out losing detail which is important of course when revewing paranormal evidence.

There are three variables that need to be taken in to consideration when taking photos. They are Lens Aperture, Shutter Speed, and Sensor Sensitivity.

Aperture

Firstly, aperture, the amount of light that is let through to the sensor from the lens. The aperture is measure in f ratio denoted as f/n where n is the aperture. The lower the f number the more light is allowed in. The higher the f number, the less light is allowed in at a time. This number is important when working with different ISO speeds. For example, if you turn up the sensitivity on the sensor to 800, then you don't want a lot of light coming in at once because the image will come out washed out. Objects near and far will appaear sharper with small apertures. Objects, except in a narrow range, will appear blurry.

Shutter Speed

When shooting at night, you will need a slower shutter speed, but you won't get great pictures of moving objects if the shutter speed is set to anything over 2 seconds.

Speed (seconds) Description
1/8000 Stops all motion
1/4000 Stops motion while walking (most entry level DSLR)
1/2000 Stops most motion
1/1000 Stops bicyclists and runners
1/500 Freezes a person jumping
1/250 Stops some motion
1/125 Avoids camera shake
1 Motion becomes Visible
2 All motion becomes visible
4 Motion starts to become invisible
8 Motion is fog like
B Keeps the shutter open as long as you want

 

As the shutter is open longer, you see motion in the form of trails. If you keep the shutter open for a longer period of time, someone could walk in to the frame, stand there, then walk away. This will leave a ghost like image of the person. I would keep the shutter speed somewhere between 1/500 and 1/125 at night. Then turn up the ISO sensitivity and have a low aperture. Since at night, there isn't as much light, having fast shutter speeds will not allow sufficient amount of light on to the sensor.

ISO Speeds

ISO speed is the sensor sensitivity. The higher the ISO speed, the more sensitive to light the sensor is. Which means on a higher ISO speed, such as 800, needs less light is opposed to when the sensor is set to 200. ISO speeds also play a part when capturing photos that have motion. Keep in mind that when cranking up the ISO, this generates more noise, or graininess. The graininess tends shows up in the shadows, with excess noise in the shadows, the more likely you will experience pareidolia.

Putting it all Together

I can't say, "Use these settings and all will be fine." You'll need to get to know your camera, as snobby as that sounds. Also, you will need to shoot in different level lights, and I suggest a tripod to help you. I have found good luck using a tripod, setting the ISO to 400 and setting the aperature to it's lowest number possible.

Also, take pictures around your house, in rooms with reflective surfaces. See how the camera picks up moisture in the air as well as dust. Camera will react differently to these things.