by Dan Feildman
Buying a new digital camera can be a very overwhelming endeavor. Technology is in a constant state of change and there seems to be new camera announcements every month! There is a way to ensure that you purchase the right camera for your needs however. Understand the technology. Not all of it of course, but just enough to make the right decisions. This article will cover the features of digital cameras that are most important for you to understand.
For starters we have to understand the similarities of film and digital cameras. In short, a camera is a light tight box that allows exposure of a light-sensitive material through the use of a shutter and an aperture. This definition does not change from film to digital cameras, nor does the process.
Lenses focus the image and control how the photo will look (wide or telephoto); both film and digital cameras have lenses. The lens is also one of the most important factors in determining overall photo quality; the better the lens quality, the sharper and more clear your image. In film or digital photography- poor lenses=poor image quality.
Both types of cameras also use shutters to maintain the duration of the exposure. Both film and digital cameras need an aperture to control how much light hits the sensor during the period that the shutter is open. Very large apertures (2.8 or 4) will let in a lot of light, while small apertures (16 or 22) will let in very little light.
Whichever type of camera you may use, focusing the camera will always be an important step in creating sharp images. Manual and automatic focusing can be found on both types of cameras. So what are the differences between the two? The main difference is the way in which it records light. The traditional camera uses film and the digital camera uses a sensor and a processor. Understanding the differences between the sensor and processor is the key to understanding digital cameras.
Film Advance, Lag and Response Time The digital sensor records light much like film cameras do. The difference is that when light strikes film it is “exposed” and the camera must advance the film to the next frame in order to allow the user to take another photograph. With digital photography, the image that was captured during exposure is passed on to the processor and the sensor is then freed up to record another image. Advance Time is the amount of time it takes for the sensor to release its information and be ready to record again. The speed of the digital camera is also influenced by how many images it can store in its memory before the camera needs a time out to process them. A typical statistic you might find could be “23 full-res(resolution) JPEGs or 6 RAW images at 5 fps”(Canon 20D). In common language this means the camera will shoot 5 images per second until the memory fills up. The memory will become full at 6 exposures if you are shooting RAW and 23 if you are shooting the highest quality JPEG.
In the beginning, when digital cameras first became popular, something called Lag Time was a major issue. The “lag” in between the time you clicked the shutter button and the time the shutter opened was very obvious. With the recent advances in technology there has been a significant reduction in lag time. Even the most budget friendly cameras have a very quick turn around time in between shots or during a series of quick exposures. If your photography requires fast shooting and many frames per second (i.e. sports photography), it would be a smart idea to research the frames per second and lag time statistics prior to purchasing.
ISO The ability to change ISOs at any time is one of the many benefits of digital cameras. ISO refers to the sensitivity of the sensor in a digital camera and film in traditional cameras. The higher the ISO setting the less light is needed to strike the film. With traditional film cameras, if you wanted to get a faster shutter speed due to low light or fast action, you needed to change to a higher ISO film. At best this could be wasteful or inconvenient . The nice thing about digital cameras is that you can change the ISO as you go. With digital cameras it is possible to be photographing outside in bright sunlight with a low ISO (for better color and image quality) and then walk indoors, you can easilty change the ISO and continue shooting.
In Digital Photography ISO measures the sensitivity of the image sensor. The same principles apply as in film photography – the lower the number the less sensitive your camera is to light and the finer the grain. Higher ISO settings are generally used in darker situations to get faster shutter speeds (for example an indoor sports event when you want to freeze the action in lower light) – however the cost is noisier shots.
This increased sensitivity does have its drawbacks however. With film you get an excess of grain, with digital you get what is called noise. The grain of film, in most cases is considered acceptable and in some cases even desired. Noise, however does not have the same allure. Unlike different emulsions of film, the sensor really only has one sensitivity. To manage an increased ISO, or during very long exposures, the camera must send more power to the sensor, which results in the appearance of small specks or dots of white or color. A blotchy look can also be created from the higher ISO’s or long exposures. Most of the noise will generally manifest itself in the darker areas of your image. This is an important point to pay attention to if your photography requires higher ISO settings, nighttime or long exposures. In higher end cameras, manufacturers have spent the money to reduce the noise problem, but it still may present itself on the lower cost models. Look to reviews for how much noise individual cameras will produce.
In today’s market almost all digital cameras have very high resolutions. You can even find less expensive cameras with resolutions sufficient enough to make a decent 8×10 or 11×14 prints. Given this you might be asking, “what is the big attraction to higher resolutions?” For the most part it is a selling point for the manufacturers! More resolution is good but what is even better, and what you want to look for in your camera, is a larger sensor size. Here the bigger the better manta comes into play. Sensor size is a much better measure of the camera’s final image quality. In film cameras, a 35mm is better than an APS camera because the size of the image on the film is bigger. There is no difference with digital cameras.
These days almost all digital cameras have very high resolutions. Even the less expensive cameras all come with resolutions sufficient enough to make good 8×10-11×14 prints. So what is the big attraction to higher resolutions? Mostly, it is a selling point for the manufacturers! More resolution is good but what is even better, however, is a larger sensor size. The bigger the better. This is a much better measure of the camera’s final image quality. In film cameras, a 35mm is better than an APS camera because the size of the image on the film is bigger. No different with digital cameras.
White Balance The processors ability to create “correct” color in your pictures is referred to as white balance. The sensor in the digital camera always captures “raw” images at which point the onboard processor processes it and then sends it to the memory card.
The human eye is excellent at ignoring color casts; however film and digital cameras do not ignore the differing light castings such as how indoor colors under typical house lighting show the color as quite orange/yellow while office lighting (fluorescent) is very green. Cameras record colors quite faithfully. When using film it is important to put filters on your camera or to purchase film that is balanced for the particular lighting (color) that you are using. With digital cameras we can easily change our white balance. All digital cameras come with a fine selection of white balance options for correcting typical lighting situations. They all will include an auto setting as well as manual settings. Automatic settings are useful if you do not know what kind of light you are working under. The more expensive cameras come with the ability to custom balance to any color light!
The human eye is excellent at ignoring color casts. When we are indoors under typical house lighting the color is quite orange/yellow, office lighting (fluorescent) is very green. Our eyes are able to ignore this, but film and digital cameras do not. They record faithfully. When using film it is necessary to put filters on your camera or to buy film that is balanced for the particular lighting (color) that you are using. With digital we can simply change our white balance. All digital cameras come with a fine selection of white balance options for correcting typical lighting situations. They all will include an auto setting as well. This is useful if you do not know what kind of light you are working under. The more expensive models will come with the ability to custom balance to any color light!
Choose a digital camera that is right for you Understanding how the sensor works allows us to make informed decisions regarding resolution and camera speed. White balance is a fairly uniform feature across the entire line of cameras (with the exception of the high end models), negating any serious consideration in this arena. Given what we have covered I am sure you are wondering what other features exist that may influence your camera purchase?
Choose a digital camera that is right for you Understanding how the sensor works allows us to make some intelligent decisions surrounding resolution and camera speed. White balance is a fairly uniform feature across the entire line of cameras, negating any serious consideration in this arena. So what other features exist that may influence your camera purchase?
Lenses Along with the sensor and processor, lenses play a major part in creating high image quality. Luckily we are at a place in time where most lenses are of a very high quality. So speed and length are the qualities that you should look at. Speed refers to the fastest -stop of the lens. 2.8 is faster than 3.5, which is faster than 4. A faster lens will allow you to shoot in lower light conditions without raising your ISO. It will also allow you to achieve a shallow depth of field, which will result in a blurred back or foreground. Buying a new digital camera
Focal length is the next consideration you should think of before purchasing a digital camera. Do you like to shoot with wide-angle lenses? Long telephoto lenses? Do you enjoy shooting up close with macro lenses? Digital cameras have all the same lens options that your film camera does. It is simply a matter of choosing the camera with the qualities that you want. By looking through magazines or surfing on to the web and going to www.dpreview.com you can easily find the specifications that describe all of the options.
When it comes to focal length it is important to remember that two sets of specifications are generally given. The first is usually the actual focal length of the lens. For example, 7mm-28mm. This would be an extreme wide angle on a film camera. The digital camera however, has a smaller sensor area then the film camera which makes the 7mm lens look more like a 35mm lens. So the second set of numbers on this lens would be 35mm-136mm. This is generally called the 35mm equivalent. When looking for a digital camera these are the numbers you should pay attention to when checking for focal range as they will be more familiar to you.
Most amateur digital cameras do not provide real wide angle lens choices. They will commonly go down to 35mm or even 28mm but rarely can you find a 24mm or wider. This is mainly due to the difficulties in building such a small focal length lenses. So if you enjoy wide angle photography you many want to think about moving up to a digital SLR.
When it comes to long telephoto lenses, however, the digital cameras have a big advantage! Their smaller sensor size turns even moderate telephotos into very long lenses. For example a real 57mm focal length behaves like a 370mm! This is a real boon to folks who like to shoot “long”. Beware however of cameras which claim their longest focal length as Digital Zoom. Digital Zoom should always be avoided. We are concerned only with real or actual focal lengths.
The last lens specification to consider is the focusing distance. If you like or need to shoot macro, look for a lens that focuses very close. They will usually be signified by a “macro mode” or be called “close focusing”.
Shooting your digital camera in the field Using your digital camera should be the fun part. Do not let all of the bells and whistles confuse you when it comes time to take your photos. We agree that there are many choices and they can be a bit overwhelming. Here we have listed three of the most important things you should always check before you start photographing.
ISO- If you are outdoors or in areas where you have plenty of light keep the ISO set to a low (100 or 50). Raise the ISO only when you need to prevent camera shake. Typically most digital cameras will provide great images all the way up to 400 ISO. If you need to go higher than 400 ISO, you must know that you may run the risk of introducing a visible amount of noise to your photos. Take some time and play with your digital camera to figure out which ISO produces unacceptable noise levels.
Jpeg vs. Raw- This is an easy choice. If you want to manipulate every photograph in your computer, shoot RAW. This format is much more flexible and enables you to correct errors in exposure and color cast without downgrading the quality of your image. If you do not have the time or desire to work on every image, then use the highest quality Jpeg mode. Jpeg mode uses a minimum amount of image compression and provides extremely high quality pictures.
Image Size- Most cameras come with multiple resolution choices. Your choices may look like this: 2304×1728, 1600×1200, 1280×960, 640×480. The rule of thumb is to always choose the highest resolution. In this case that would be 2304×1728. The highest resolution will supply you with the highest quality images possible.
Digital Camera Accessories To say that there are a lot of accessories for the digital camera would be an extreme understatement! It can boggle the mind with all of the different options, cases, cards and storage units. There are however, only a very few accessories that are absolute necessities.
Compact Flash-The first accessory is the type of storage medium that your camera uses to store your photographs. I prefer cameras that use Compact Flash as I have found this medium to be the best all around Flash Card. Compact Flash cards are sturdy, durable, not too small to lose or to big to be bulky. They also come in very large capacities-up to 8 gigabytes! Personally I recommend that people should have at least two cards in case one card becomes damaged or lost. How much you want to spend will determine your total amount of storage (cameras rarely ship with a card that is adequate for most photographic purposes). Having two 512Mb cards might be enough for most shooting situations, unless you take loads of photographs. Having 4 of these cards or two 1 GB cards will ensure that you will never be without storage.
Portable Storage-If you have enough Flash Card storage, you will probably not need a portable storage unit. This theory dependent on moving your photographs from the cards to your computer on a regular basis. For instance, if you are on vacation and will not have access to your computer for long periods of time you may want to consider a portable storage unit. The most basic form of a portable storage unit is one that allows you to plug your card into the unit, and download your images to it. You can then put the card back into your camera, reformat it to remove the existing photos, and continue shooting. When you return home you can simply hook the storage unit to your computer and move the images. Typically these units come with enough storage space for many days of shooting. A good purchase would be a unit with at least 10Gb of storage.
Storage and transfer are the most basic function which all of the models will perform. From here they can get really fancy. There are units that will automatically burn Cds from your cards, which produces an immediate archive of your images. Others come with an Lcd screen that allows you to view your images right on the storage device. Advanced features will even enable you to organize your images into folders and albums. Think about the length of time you will be away from your computer before purchasing one of these storage units. You may not need one.
Extra Batteries / Charger Digital cameras use batteries at an alarming rate. You will definitely need to have back up batteries. Because you will be using so many, rechargeable batteries are the intelligent choice. Most digital cameras come with a proprietary battery with a charger. This is a good thing as it allows a stronger battery. If this is your situation, purchase extra batteries when you buy your camera. If your camera is powered by common AA batteries, you would be wise to buy a couple sets of rechargeable batteries.
Bulb blower- this is a must if you are considering purchasing an interchangeable lens SLR. Often when you change the lens on these cameras dust is introduced into the camera body. Ultimately the dust will migrate to your sensor and manifest itself as small blurry splotches on your final image. A few seconds with the blower bulb will save you hours on the computer cleaning up your photographs!
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