Monday, October 27, 2008

Purchasing a new digital camera

By Dan Feildman

When it comes time to purchase a new digital camera you might feel a bit overwhelmed. With technology constantly changing and new features available every month it is easy to be confused about what to purchase. However, there is a way to ensure that you purchase the right camera that will meet your needs. The key is to understand the terms and technology. You might not understand all of it, however it is our goal to give you enough information to make an informed decision. This article covers the features of digital cameras that are most important for you to understand.

To begin with me will discuss the similarities between film and digital cameras. Basically a camera is a light airtight box that allows exposure of a light-sensitive material through the use of a shutter and an aperture. This process is the same with either a digital or film camera.

Both film and digital cameras have lenses, which allows you to focus the image and control how the photograph will look (wide or telephoto). The lens is also one of the most important factors in determining overall quality of the image. The better your lens quality, the sharper and more clear your image will appear. Regardless if you are using film or digital photography - poor lenses = poor image quality.

Shutters control the duration of the exposure in both types of cameras. Both film and digital cameras use an Aperture to control how much light hits the sensor during the time frame 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.

Focusing will always be a necessary step in creating sharp photographs regardless of whether you are using film or digital cameras. Manual and auto 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 the cameras record light. The traditional camera uses film while the digital camera has a sensor and a processor. Understanding the way the sensor and processor work is the key to knowing digital cameras.

Film Advance, Lag and Response Time The digital sensor takes in light much like film. Once the light strikes film it becomes"exposed" and the camera must advance the film to the next film frame to carry on the development. With digital cameras, the information that was acquired during exposure is moved on to the processor and the sensor is then freed up to grab another image. The length of time it takes for the sensor to "unload" its information and be ready to record again is called Advance Time. The speed of the digital camera is also influenced by how many images it can retain in the memory before the camera needs a time out to process them. A typical statistic could be "23 full-res(resolution) JPEGs or 6 RAW images at 5 fps"(Canon 20D). All this means is that the camera will shoot 5 frames 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.

ISO One of the many benefits of digital cameras is the ability to change ISOs at any time. ISO refers to the sensitivity of the sensor in a digital camera and film in traditional cameras. The higher the ISO the less light you need to strike the film. With traditional cameras, if you needed to get a faster shutter speed because of low light or fast action, you needed to change to a higher ISO film. This could be wasteful or inconvenient at best. With digital cameras you can change the ISO on the fly. Now it is possible to be photographing outside in bright sunlight with a low ISO (for better color and image quality) and then walk indoors, change the ISO and continue shooting.

Resolution Resolution is arguably the least understood and most talked about feature of digital cameras. The more resolution the better is what the general consensus is. However this isn't always the case, more resolution doesn't always mean better photographs.

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 8x10 or 11x14 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.

Please don't forget, it is common to see cameras that are equal in resolution but have different size sensors. In cases like this I would go for the larger sensor. So how can you figure out how much resolution you do need? It's very simple really. Just ask yourself how large of a picture do you want to make. The 3 and 4 Megapixel cameras are plenty sufficient for everything will print good quality pictures up to 8x10. If you want to make larger printsyou can move up to the 5 and 6 Megapixel cameras.

Remember, it is common to see cameras that are equal in resolution but have different size sensors. In this case I would go for the larger sensor. So how do you know how much resolution you do need? Simple really. Just ask yourself how large of a print do you want to make. The 3 and 4 Megapixel cameras are plenty sufficient for everything up to 8x10. If you want to make larger prints you can move up to the 5 and 6 Megapixel cameras.

The human eye is an amazing thing. What is even more amazing is that it is excellent at ignoring color casts. When we are indoors under typical house lighting the color is quite orange/yellow while office lighting (fluorescent) is very green. Our eyes are able to ignore this, but film and digital cameras faithfully record all color nuances. When using film photography it is often necessary to put filters on your camera or to purchase film that is balanced for the particular lighting (color) that you are using. With digital photography we can easily change the white balance. All digital cameras come with a good variety of choices for correcting typical lighting situations with white balance. They also generally include an auto setting as well which is useful if you do not know what kind of light you are working under. Typically the more expensive cameras will also include the ability to custom balance to any color light!

So if your light is Then the color is Choose this White Balance for good color Daylight Neutral ("white) Daylight Late Afternoon/Sunset Warm (yellow/orange) Daylight Early Morning Warm (yellow/orange) Daylight Cloudy Cool (blue) Cloudy/Overcast Open Shade Very Cool (blue) Open shade Unknown Light source ??? Auto Tungsten/Incandescent Very yellow/orange Tungsten/Incandescent Fluorescent Green Fluorescent

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?

Lenses Lenses play a major part in creating high image quality, along with the sensor and processor. Luckily in todays marketplace we are at a place in time where most lenses are of a very high quality. So we now know that 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 allows you to shoot in lower light conditions without raising your ISO. It also allows you to achieve a shallow depth of field, which should 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 prior to purchasing is the focusing distance. If you like, or need, to shoot macro, look for a lens that has the ability to focus 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- Keep it set to a low (100 or 50) if you are outdoors or in areas where you have plenty of light. Raise it only when you need to keep from getting camera shake. Most digital cameras provide great images all the way up to 400 ISO. If you need to go higher than 400 ISO, you can run the risk of introducing a noticeable amount of noise to your photos. Play with your digital camera to figure out which ISO produces unacceptable noise levels.

Jpeg vs. Raw- This choice is an easy one. If you want to work on every image in your computer, shoot RAW. This format is much more flexible and allows you to correct for errors in exposure and color cast without degrading your image quality. If you do not have the time or desire to work on every image, then shoot in the highest quality Jpeg mode. This mode will use a minimum amount of image compression which will provide extremely high quality pictures.

Image Size- Most cameras come with multiple resolution choices. Your choices may look like this: 2304x1728, 1600x1200, 1280x960, 640x480. The rule of thumb is to always choose the highest resolution. In this case that would be 2304x1728. 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 an ample amount of Flash Card storage, you will not need a portable storage unit. This is however contingent on downloading your cards on a daily basis. If you are in a situation where you 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 storage is one that allows you to plug your card into the unit, and download your images. You can then put the card back into your camera, reformat it, and continue shooting. When you get home you simply attach the storage unit to your computer and transfer the images. Most of these units come with enough storage space for many days of shooting. I would consider a unit with at least 10Gb of storage.

Storage and transfer are the most basic functions which all of the models will perform. At this point they can get really fancy. There are units that will automatically create Cds from your cards, which produces an immediate archive of your images. Others come with an LCD screen that allows you to preview your photos right on the storage device. Advanced features will even allow you to organize your images into folders and albums. Prior to purchasing one of these units you may want to think about the length of time you will be away from your computer as you may not need one with these advanced features.

Extra Batteries / Charger Digital cameras go through batteries at an alarming rate. You will definitely need to have back up batteries. Given that you will go through so many batteries, rechargeable batteries are the intelligent choice. Most digital cameras come with a proprietary battery with a charger. This is helpful as it allows a stronger battery. If this is your situation, it is a good idea to 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! - 15485

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