Digital Photography

 

Digital cameras are a fairly recent innovation first appearing on the high street less than 10 years ago. The early models were horrendously expensive and produced images with low resolution and poor colour rendition. Battery life was also a serious issue as was the cost of the memory media needed to store the images. With the advent of improved technology, some of it developed originally for mobile phone uses digital cameras provide relatively low cost and reasonably decent quality images that have the extra advantage of being immediately viewable via the on-camera LCD screen, TV or a computer. Once the camera and sufficient memory is purchased then there are usually no further costs involved for the user. Printing may be done without even the need for a computer, high street stores allow the user to simply take along the memory card and the selected images can be printed just like a normal photograph. Printing can also be done at home or even at the investigation location using stand-alone portable printers costing less than £100.

                      

Digital Film

No, not a mistake as this is the description now commonly used by some memory card makers to describe the memory cards upon which the actual image data is stored after taking. Actually, this terminology is misleading as the memory card is perhaps better compared to a photo album. The best analogy for the film being the imaging chip as this is where the light is directed by the lens - exactly as light is directed onto the film in a 35mm camera. Instead of film, the digital camera uses a silicon chip to turn the light into electronic information. There are two types of silicon ship in use - the CCD - Charge Coupled Device and the CMOS - Complimentary Metal Oxide Semiconductor. They both do the same job however and we do not need to worry too much about the differences here.

The ability of the imaging chip to resolve detail within the scene being photographed is a function of two variables; the number of individual light gathering points (pixels) on its surface and the physical dimensions of the chip. Generally however, most manufacturers simply quote the number of Mega-Pixels - Millions of individual pixels on the chip when promoting the specifications of a camera model. We will see later that chip dimension is also a factor that some may wish to consider when choosing a digital camera to use on their paranormal investigations.
 
It is important to note that even if one spends many thousands of dollars on a digital SLR the end result will still only contain less than 50% of the original information in the scene when compared to a similar film image. The fewer the number of Mega-pixels correspondingly even less information is available in the final image. Our eyes normally do not notice this lost information as we rarely enlarge a picture beyond a 7"x5" or perhaps a 10"x8" print size - blow up the image further and the fine detail will be missing, and this may be an issue in some situations where that information may hold vital clues and may mean the difference between an anomaly or an identified object.

The pixels on the chip cannot resolve colour so the light first needs to be passed through a filter that allows colours to be 'seen'. This filter has lead to some comments that digital images have 'false colour information' to an extent this could be true but it is also the case that 35mm film also uses a filter within the structure of the film in order to resolve colour in a scene.
 
 
Digital Darkroom

Film cameras simply expose the film to the light - as already described the film is then taken out for developing and printing in order to reveal the final picture. Within every digital camera there is a built-in developing lab that produces a finished image almost instantaneously. The information about the light hitting the chip is transferred directly to a micro computer within the camera and it is this that then turns the raw data from the chip into a final image - just like a darkroom. This can cause some problems in itself as we are reliant upon the camera manufacturer to programme this computer to do an effective job of this process. Some digital models allow the user to store the image information in the form of a 'RAW' file. As the name implies this is the raw data from the image chip which can be worked on later using a computer in order for the image to be seen. Here again, we have to be aware that the final image will be the result of a subjective process by the user - they will produce a picture they consider is as they wish to see it. Of course many of these dilemma can be levelled at film photography too - the darkroom process or the settings of a commercial D&P machine are also largely subjective or at the discretion of the manufacturer.

 

Digital Camera Types

Broadly speaking there are two main camera types in this category although to try and properly reflect available technology we will actually divide the range if digital cameras into 3 groups; Compact, Bridge (Hybrid) and Digital SLRs (DSLR).
 

Compact

Entry level models can be bought very inexpensively these days - less than £50 for a 3 Mega-pixel model. The Lens is usually 'fixed focus' and will generally do a reasonable job of anything between about a 10cms to infinity. The aperture is also normally fixed and the exposure control is carried out electronically at the image chip.
Perhaps to be expected these cameras produce the least good images with the highest incidence of picture problems, unless one is on a really tight budget and is aware of the potential drawbacks then these cameras really ought to be avoided as they are simply not up to the task of gathering evidence. Perhaps there only use is as a visual sketchbook allowing the user to make a quick note of something such as the layout of a location for example.

In the mid range the user is almost spoilt for choice with a vast range of cameras having between 4 and 8 Mega-pixels supported by a wide range of settings and options that allow the user the tailor the cameras abilities to their specific needs.


The same problems highlighted with film cameras also apply here too - perhaps even more so with the many facilities modern cameras can offer. Many users simply do not properly read the manual and take the trouble to learn how to best use these features, instead they turn the camera on and shoot away with the fully automated settings taking care of the picture settings. This will produce good pictures but often does not allow the best image to be obtained. Read the manual and experiment with the different settings. This is easy to do with a digital camera as it involves only time and time that will be very well spent.


The main thing to consider is the electronic 'apparent' sensitivity of the chip to light. Quoted for ease in ISO units the same as film the lower the number the better the final will normally be as the camera requires less electronic amplification (gain) to be needed. A faster setting (higher number) will allow pictures to be taken in situations of less available light but with a corresponding increase in amplification needed and a lowering of the image quality - experiment under investigation conditions to find the best image quality to suit your investigation needs.


There has been a recent trend amongst camera manufacturers to produce very small cameras - around the size of a credit card in some cases. This means a smaller lens and a small image chip and that will reduce overall quality however expensive the camera may be. The user may be prepared to accept a trade-off between an easily portable camera that fits neatly into their pocket and is always available and the slight loss of final image quality however.


Compact models also tend to have the flash closer to the lens axis, allowing the flash light to be reflected from objects onto the chip more readily. This is a known cause of many of the phenomena paranormal investigators refer to as 'Orbs'. The incidence of red-eye' effects is also higher is these type of cameras, great for making the other investigation team members look demonic!

Another setting that you should notice of with compact, indeed ALL digital cameras is the amount of image compression that is applied to the final image when it is 'written' to the memory card. Most camera makers allow the user to select this setting although some may label it as 'Image quality' instead. In order to fit the finished images onto the memory card the data needs to be compressed and this does mean more lost information when compared to the original scene. By choosing either a lower compression or a finer quality setting you will get less images onto the memory card but each will be of a higher quality. Most cameras store the final image as a jpg (jpeg) file, some allow the user to select storage as an uncompressed .tiff (TIFF) file instead - this means fewer images but a lot more original information is retained in the final image and that may be important for any subsequent analysis and determining what an anomaly actually is. One or two models even allow files to be stored as RAW file data which is allows ALL the available information from the chip to be examined although this method will require the further use of a computer to write the final image.


Cameras are supplied with a memory card that is barely adequate in terms of storage abilities usually allowing only a few of the highest quality images to be stored on it - memory cards are nowadays inexpensive especially compared to their costs just a year or two ago, buy a large memory card - at least 512Mb or better a 1Gb card and you will be able to store all the images you'll need for any investigation.


As a general rule of thumb go for a model by a well known camera maker with a lens of at least 25mm diameter and with a flash that 'pops-up' taking it further from the lens axis. A larger lens diameter is perhaps better than a couple of extra Mega-pixels too so don't just make your choices based solely upon the pixel count.

 

 Bridge or Hybrid Cameras

This type of camera is a new development and has only really been around for about the past year or so. They are a mid-point between the DSLR and the compact taking some the best features of each and would on the surface seem like the ideal camera for the investigator. They are a compromise and they do have a number of drawbacks although the makers are constantly evolving them to make them ever better.

This type of camera usually has a high pixel count - sometimes into double figures and often too a large zoom lens with a large diameter. The flash is also more powerful and pops up to a good height above the lens reducing some of the problems mentioned earlier. These models are heavy in added features and modes including full manual settings and this means they can be tailored for specific types of picture taking requirements which will suit the paranormal investigator well. One day it can be used on a site reconnaissance visit and later can take excellent images in a darkened room. The zoom lens allowing wide angle shots to take in whole scenes or close-ups of more distant features.

These cameras are normally quite large and chunky which for some people means that they are difficult to carry around all the time but the effort is usually well rewarded in terms of improved image quality over their compact brothers. The larger body often allows the maker to fit a larger LCD screen for setting-up and viewing final images and the screen may also be able to be rotated and tilted to allow better camera positioning whilst still being able to set-up the shot.

Best of all the image chip is normally physically larger too which means a further improvement in image quality - some recent models actually use the same image chips as the more expensive DSLR type of cameras. The fact that the lens is permanently attached to the body also is an extra bonus to the paranormal investigator. Looked at in more detail later dust on the image chip is a major cause of problems for DSLR users and in the Bridge design the sealed body / lens means dust cannot penetrate and create the problems of image anomalies that may be later interpreted as being of paranormal origin.

The viewfinder is normally in the form of an electronic viewfinder or EVF and not of the direct optical type such as is found on DSLRs, some of these EVFs are a little difficult to use with some subjects but most users tend to use the LCD screen so this is not a major drawback.

Bridge cameras may be amongst the best all round solution for the paranormal investigator and although they are a compromise they do on the whole represent an amalgam of the best from the easy to use compact models and also the top of the range DSLRs. Used with care and with the proper amount of time taken to learn and experiment with all the extra features these cameras have available then Bridge cameras should be high on the list of useful tools for the paranormal investigator.

 

Digital Single Lens Reflex - DSLR

Simply, these cameras are not unlike 35mm SLRs with the main difference being that instead of film, a large image chip is used instead. They use a mirror and prism arrangement to bounce the light coming through the lens up to a viewfinder, the mirror moving out of the way and a shutter opening to expose the image chip to the light at the time the picture is taken. There are two main advantages of DSLR cameras; they use a much larger image chip and they use lenses with a large diameter and thus a wider available aperture for lower light use. Another key advantage is that they allow the user to change the lens to suit their specific picture taking requirements. They are normally part of a 'system' with several lenses, flashguns and lots of specialist accessories, further allowing their use to be specifically tailored to the users needs.


It is this 'system' concept that may offer some users a further and important advantage - most DSLRs are also backwards compatible with 35mm SLR systems and this means that users with existing lenses and accessories have no need for further investment.

A major problem for many DSLR owners is dust gathering on the image chip itself. Every time a lens is changed dust inevitably gets inside the camera body and some of it will get onto the surface of the image chip. Dust also gets inside 35mm film SLRs too but as the film is wound through the camera the amounts are not allowed to build up to excessive levels. Even small dust and pollen particles are larger than the individual pixels on the chip surface and so block the light falling onto any pixel that becomes obscured in this way. This results in dark patches on the final image and other anomalies.


The only method of dealing with this dust build up is to have the image chip surface cleaned a task that most people prefer to have a professional carry out as it is an extremely delicate operation and can permanently damage the chip if not done properly. One camera maker uses a special filter that vibrates 35,000 times per second to shake the dust onto a sticky collector pad and thus prevents the dust from getting onto the chip. So far this is the only effective in-camera solution that is available.

 

The Real Digital Film


The imaging chip - the actual 'film' within a digital camera was discussed earlier in this article however it is a good point to look again at the various chip options and consider some of them in more detail.
Rather than examine the technical differences we shall consider these differences in terms of the advantages or otherwise to the paranormal investigator, for those who seek more technical information then a search of Google will reveal many sites that will provide all the information they seek.


The imaging chips of both types, both CCD and CMOS are used by the camera manufacturers in a range of options but just two need be given any real thought when considering a cameras suitability for the needs of the paranormal investigator - they are the physical size of the chip and the number of individual light gathering sensors (pixels) on its surface. As stated previously most camera manufacturers quote the pixel count in the main specifications and advertising and it is usually true that the more pixels a chip has then the greater amount of information it is able to resolve within any scene. As with many things there is always a downside otherwise the makers would simply develop chips with increasing pixel counts and leave it at that.


For any given physical size of the chip, the more pixels inevitably they will be smaller - down to less than 3 microns in some compact and bridge models. The smaller pixels are correspondingly less sensitive to light than those of similar technical specification but larger size - in some DSLRs 5-7 microns is more common for example. In bright daylight scenes this may not be a serious issue as there is plenty of light available but indoors or at night these chips start to show their weakness. Correspondingly more amplification is then required to obtain useful data from the chip and the more amplification that is needed then the greater the amounts of electronic 'noise' will be present in the form of degradation in the final image. Electronic noise also produces anomalies in the image itself which may be interpreted as being paranormal by the unwary investigator. Manufacturers normally limit the range of sensitivities of these small chips - some only offering ISO equivalents of 100 to 400 and this may seriously limit the cameras usefulness in low light situations.


Larger chips allow the inherently better sensitivity to low light levels to be exploited and the manufacturer can offer the user a greater range of ISO equivalents - in some cases ISO numbers of 1600 or even 3200 are possible without excessive electronic noise being a problem. The larger pixels also allow for a greater tonal range to be captured from the scene and this will result in a more accurate scene rendition even at lower light levels.
Physically larger chips force the maker to provide a physically larger lens diameter too and such lenses normally have wider apertures and better optics so further improving the overall image.


Of course, as camera makers develop the electronics within the cameras over successive models they are able to better control the noise and low light weakness of the smaller chip so that they start to offer a very similar specification to the user. Some Bridge models offer double Mega-pixel chips that are barely larger than those in compact cameras. This is done with additional electronics and processing after the chip and improvements in the design of the pixel elements too - a microscopically small lens over each pixel element improves light gathering for example. The limits of small form chip design may be being reached however, most recently some makers have actually reduced the number of pixel elements on these chips because they found that they were becoming 'too noisy' and image quality was suffering.


The large chips too are not without problems. These are essentially the same problems that apply to their smaller cousins. As makers vie with each other to cram ever more pixels onto the chip the pixels have to shrink in size. Because they have a larger form to start with however we are still some way from reaching the limits of image chip design just yet. As an example if the smaller pixel designs were used on a 35mm 'Full-size' chip as is used by both Canon and Nikon then the resolution of the ship would exceed that of 35mm film i.e. over 35 Mega-pixels!


When one is looking at the specifications of any digital camera both these factors need to be considered as they affect the overall size of the camera, the lens and the usability of the camera. Small cameras are portable and often easy to use but they have smaller image chips and so perform less well in lower light. Larger cameras perform better in low light but may be left behind when needed most.


Before leaving the subject of the image chip we need to look at some further issues that may affect the image quality. In the past CMOS chips were of low resolution and typically only ever used in webcams, mobile phone cameras and the cheapest digital camera models. This changed recently with the development of high resolution CMOS chip designs. The CMOS works slightly differently than the CCD design, this difference means it can transfer its data to the camera processor faster - not so important for the amateur but an important issue for some professionals such as sport photographers. We are now starting to see camera makers such as Canon and Sony using CMOS chips in their top end amateur models.


One of the most frequently stated reasons for using a digital imaging chip by paranormal investigators is perhaps the ability of chips to 'see' in the Infra-red part of the spectrum. It should be pointed out that all imaging chips have about the same degree of sensitivity to IR light but most makers choose to apply filters to remove it as it can affect the colour rendering of a scene in normal light conditions. Sony have made a feature out of this extra sensitivity to allow pictures to be taken in conditions were there is little or no visible light. Although it is mainly used in their video cameras, some of their still cameras also exploit this ability and permit Infra-red (IR) still photographs to be taken in locations where there is almost no ambient visible light. The ability of these cameras to 'see in the dark' is further enhanced by the fitting of Infra-red emitting LED lighting which illuminates the scene with light that the camera can see but we cannot.
Many paranormal investigators claim that paranormal manifestations are more visible under IR light or that they emit IR light which can be 'seen' by the chip, this is highly contentious and as yet unproven but it does mean that locations can be photographed under conditions of extremely low light which may aide the investigation process. It also cannot be a bad thing if paranormal investigators have a tool that allows them to take pictures over a broader portion of the light spectrum.

 

 Digital Conclusions


Digital photography offers the paranormal investigator a means of taking almost unlimited numbers of photographs without additional costs after the initial outlay on equipment and memory card/s. Once the card is full it can be downloaded to a laptop or one of many portable hard disk devices that are available for around $100 - $200 allowing more pictures to be taken. Pictures can be viewed immediately on the camera's LCD screen or on a computer or even a TV screen.


Digital images are of lower resolution that even similar pictures taken with any 35mm film camera, even the most basic models. The image also has less information within it which may be critical for some situations.
Digital images are also prone to problems of electronic noise caused by the further electronic manipulation needed within the camera in order to produce an viewable image. Individual pixels may become faulty leading to anomalies within the image that may fool the unwary investigator. Dust may also cause problems in most DSLRs and may lead to anomalies appearing in the images produced if not dealt with.


One often overlooked problem with digital cameras is their need for power - all require batteries and many use them quickly, sometimes failing to last for a whole night's investigation. Rechargeable batteries are one solution to this, battery technology developed from mobile phone use providing some models with plenty of life. Using the flash, zoom and the LCD screen use up much of the battery life and temperature too, plays a important role in how long the battery lasts, the colder it is, the shorter it will last. This temperature sensitivity of the batteries can result in the camera being apparently affected in some weird and some may claim paranormal way. 'My battery was fully charged but when I tried to take some pictures it refused to work - later, when I tried again it was working perfectly, it must be paranormal!' In reality, the batteries were too cold for the chemical reaction to take place properly and so there was insufficient power for the camera to operate, the camera is returned to the bag or pocket where it warms sufficiently to permit the battery to function and the camera starts to work again. Some types of Rechargeable batteries (notably the older NiCad types) may also have another trick to play on the unsuspecting investigator - they are designed to deliver their output voltage in a more stable way that Alkaline or other non-rechargeable batteries do. In a non-rechargeable cell, the chemical reaction steadily slows as the battery is used - the output voltage dropping steadily throughout until finally reaching a point when the 'Battery Low' warning flashes, at this point the user may still have almost 20% of the battery life still available and can keep on shooting for a bit longer before the battery must be changed. In a rechargeable battery the battery delivers a constant voltage throughout the period of use until the chemical reaction is exhausted, the battery will then fail quickly often without the low battery warning having time to alert the user.
It is therefore always a good idea to carry a 2nd set of batteries otherwise your expensive camera is just about useless and you can be sure that they will run out just when you need the camera most!

Perhaps the final issue with digital photography that applies to all camera types is that manipulation of image is a simple task and the sceptics will also say that with digital images fakes are easy to produce. There is also no negative to act as a further safeguard against 'created' images. This can be partially got around by developing good protocols for handling the data both in camera and afterwards in the computer. Modern cameras write secondary information - the EXIF data which contains information about the camera, the settings used at the time of taking along with date / time information too. Most photo software allows the user to show this information but unfortunately some software also allows it to be re-written too, reducing the effectiveness of this method of reducing fraud.

Many of the issues with digital photography can be accepted as a compromise against its immediacy and very low cost per image. Digital photography will soon become the dominant form of photography and paranormal investigators and also the sceptics need to accept that and work toward minimising some of the problems currently associated with this form of picture taking.

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