By Mary Kolenick
Marketing gurus love to splash the number of megapixels a camera can use in all of the advertising as though it is the most important feature of the camera. They even sometimes slap a sticker on the camera as though you are going to say to your friends "look, my camera has more megapixels than yours." You would never do that, right? In reality, today's digital cameras have more megapixels than most of us will ever need.
Megapixel is short for one million pixels. That probably doesn't help you much, so let's start with some basics. Think about the picture you want to take. You see a scene before you and you frame it in your camera's viewfinder. To turn what you see into a digital image, your camera has to capture the scene, translate it into numbers, and store those numbers in a file. It does this by breaking the scene into small discrete points called pixels where each pixel is a number representing a color. Your computer will later take those numbers and translate them into pixels on your screen to show you the image. If a camera breaks a scene into 2048 pixels across and 1536 pixels down, that is 3,145,728 pixels total (multiply 2048 by 1536).Mega is the prefix for a million, thus the image is 3.1 megapixels. If a camera breaks that same scene into 4096 pixels across and 3072 pixels down, the image now has 12,582,912 pixels, or 12.5 megapixels, and much greater detail. Technically, I really oversimplified the pixels. I left out a whole bunch about color and the sensors on your camera and how many bytes make one pixel and other stuff. But many websites discuss this topic in depth if you want to learn more.
A digital image with 12.5 megapixels of information will have more detail than the same scene with just 3.1 megapixels of information. But there is a downside to using more megapixels - they take up space and time. The camera has to write all of those megapixels to some type of storage media or memory card. The more megapixels in the image, the more space on the card used for each image and the more time it takes to write the image to the card. That translates into fewer pictures you can store on the card, and more time before the camera is ready to take the next picture. But all of that detail is only useful if you intend to make large prints, provide electronic images for printing in a publication such as the CFA Yearbook, or enlarge portions of an image. You don't need it for website images or anything sent in an e-mail.
Is a camera that can take 12.5 megapixels worth the extra money over a similar camera that only takes 10 or 8? If everything else is the same or nearly the same, the answer is maybe, maybe not. I recommend using other factors to determine which camera is better for you, such as the size of the LCD display, the weight of the camera, cost, the zoom lens, etc. If my choice were between a 10megapixel camera with a 3" LCD vs. a 12.5megapixel camera with a 2.7" LCD, I would go with the 3" LCD. I need reading glasses, so the larger LCD will be more useful to me than those extra two megapixels. Megapixels are important, but they should not be the defining reason for choosing one camera over another unless you have a specific need for more megapixels.
Camera shake - the bane of many a good photograph! Image Stabilization (IS) is a technique that reduces blurriness caused by camera shake, or slight movement in either the camera or the subject. Different manufactures use different names - vibration reduction, optical stabilization, super steady shot, shake reduction, etc. While each manufacturer uses their own special technique, the intent is always to help you get sharper images. This is an incredible advance in digital photography, especially for cat photographers. Fast moving frolicking kittens are often fuzzy in photos not because of anything the photographer did, but because kittens move suddenly. IS can keep those kittens in sharper focus. The technology cannot work miracles, but when I started using a camera with IS, I noticed a difference immediately. Many more pictures were in focus and a higher percentage of my kitten photos had the whole kitten in focus. If you have a digital camera that does not have IS, it's time to ditch it for a new one that does.
The one big disadvantage of a P&S camera for the cat photographer is the fps speed of the camera, and yet few people pay attention to this benchmark when looking for a camera. Most P&S cameras have very low fps speeds in the range of 0.5 to 1.5 while digital SLRs are much faster ranging from 4 to 6 fps. When you are shooting pictures of frolicking kittens and you've just taken a cute shot, the next cute shot might happen within a split second. If you have to wait a full second before your camera is ready, the kitten will most likely move and there goes your cute shot. With a camera that takes 4+ fps, you can take several pictures in a row of a moving kitten and have a better chance of one of the shots being nice. The faster fps of the digital SLR makes it very attractive for cat photographers, but some may be satisfied with the fps of the P&S models. This is a good reason to try the camera out in a store before buying it.
Instead of film, digital cameras use some type of storage media (or memory card) to record images. There are a variety of memory cards in use today among the various manufacturers: memory sticks, SD cards, SDHC, compact flash, and more. For most uses of the camera, there is no particular advantage of one style of memory card over another. Memory sticks are not superior to SD cards which are not superior to compact flash for general uses. But the variety of these cards can present problems.
If you already have a digital camera and want to get a new one, you will have to make a choice - stick with the same brand so you can keep using your memory cards (that is if that company continues to use those same cards), or buy a different brand with a different type of card forcing you to buy all new memory cards as well. Fortunately, the price of memory cards dropped dramatically over the years and you can now get fast 8 GB (gigabyte) or 16 GB cards for what you would have spent on older 512 MB (megabyte, 1000 megabytes = 1 gigabyte) cards. This means buying new memory cards is not as costly as it used to be and it is worth it to look at cameras made by all manufacturers. What is most important about memory cards is that you purchase fast memory cards, large memory cards, and the right memory cards for your camera.
Memory cards usually come in various speeds, with faster cards naturally being more expensive. The reason you need to care about the speed of memory is that with faster memory, your camera can write the image to the card faster and be ready to take the next shot quicker. And this lag time is noticeable with slow memory. For example, SD cards come in three speeds - Class 2, Class 4, and Class 6 with 6 being the fastest. If you are thinking about using the movie feature that comes with most digital cameras today, you will need at the minimum a 4 GB Class 6 card, and I recommend having several cards on hand for any special event. If you want larger cards, 8, 16, and 32 GB cards, make sure your camera can use the high capacity card. Buy fast and large cards, but always check your camera's specs to be sure it can use the card you buy.
One last thing about memory cards, and that is where to buy them. When you buy your camera, you will most likely need to buy a memory card at the same time unless you already have cards. But the memory card is where camera shops really mark-up the cost. You can find the best prices by comparison shopping on the internet or by using eBay.
Reprinted with permission, CFA Online Almanac, September 2009; December 2009
Share with your followers.
This program is supported by
The Cat Fanciers' Association, Inc.
This program is supported by The Cat Fanciers' Association, Inc.