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How does a digital camera work?
by Digital Darrel

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  Operation, Storage & Printing
Zoom lens range, storage media & what to buy


Most digital cameras allow you to zoom in or out to change the perspective of the image. Be careful of digital cameras that do not have the word "optical" in the sentence discussing the zoom range.

Nikon 8 Megapixel Coolpix 8700 and the 6 Megapixel D100 DSLR

If your camera only has a digital zoom, it is not really a zoom. An optical zoom actually allows you to change the "field-of-view" of the image, so that you can widen out for a landscape shot, or zoom in for a portrait. It does this by moving lens elements to change the focal length of the camera's lens. Some of the best optical zooms can be as much as 10-to-1 (10x). Most medium priced digital cameras will have a zoom in the 6-to-1 (6x) or 3-to-1 (3x) range. Just BE SURE that you're buying an optical zoom.

In cheaper digital cameras there may be an attractive "digital" (not optical) zoom range mentioned. Usually it will be about 3-to-1 or 4-to-1. The problem with a digital zoom is that it is not a real zoom. The image is simply being magnified and a section of the image taken out of the middle. It is the same thing as if you took a film picture and cropped out everything except a person in the image, then made a big enlargement. You would then only be using a small section of the negative, so grain will increase and sharpness will degrade very quickly. With "digital" zooms, the image is magnified or cropped electronically and the image simply has larger pixels. You are not really zooming in on the subject. Instead, the subject is being electronically magnified, with image degradation as a result. Stay with an optical zoom for best results.

Many cameras come with a combination of optical and digital zooms. That's okay, since the digital zoom is not used until you have maxed out the optical zoom. If you really need that much zoom, though, you might just want to use the old fashioned "sneaker-zoom" whereby you walk toward the subject to make it bigger, or away to make it smaller. Or, you could buy a digital SLR (DSLR) camera and one of those huge long lenses you see at football games.


This varies with the camera manufacturer, so you are only limited by the specific camera you buy. Many cameras allow the use of the very common Compact Flash or CF card. This is a little card about 1/2 the size, and a little thicker, than a business card. It can hold up to hundreds or even thousands of images. Other memory types are Microdrives (MD), Smart Media, Secure Disk (SD), Memory Stick, or even a floppy disk, or CD.

You will need to find out for sure just what type of memory card your camera uses to store pictures. I suggest owning at least two cards. Most will come with an 8 or 16-megabyte "starter card," which will hold only a few pictures unless you set the camera to its lowest resolution. In my opinion, an absolute minimum for today's cameras is a 128-megabyte card. You should really try to get a 256-megabyte card, or even larger if you do more than make an occasional snapshot. The common sizes are: 8, 16, 32, 64, 128, 256, and 512 megabyte. Also, you will find 1, 2, or 4 gigabyte cards and microdrives. The cost for storage cards vary from around $25.00 USD to over $1,000.00 USD.

The really inexpensive digital cameras do not provide an external storage card. They store the pictures in internal memory. Unfortunately, this memory usually won't hold many pictures, so you are very limited. Personally, I would not consider using a digital camera with only internal memory, unless it was all I could afford.

I use a couple of IBM® Microdrives with their one-gigabyte capacity. One of them is equal to eight 128-megabyte cards. The IBM© Microdrive is a tiny hard drive like the big one in your computer, but fits into your camera. Only a few higher-end digital cameras will use the Microdrives though. The bigger the storage -- the greater the cost. Try to get a 128-megabyte or even a 256-megabyte card for your camera, since you will have the freedom to really use your camera with that much storage. If I set my camera to a lower resolution setting using JPEG mode, I can put over 1,200 images on a 1-gigabyte Microdrive.

Compact flash seems to be the most common type of memory card in use these days, so your costs should be a bit less for them due to competition.


As newer and denser sensor chips are developed the megapixel rating of cameras will increase, until eventually we'll have gigapixel, and maybe even terapixel cameras. This is a lot like computers. Remember back when your home computer was rated in mere megabytes. Right now the latest computers are rated in gigabytes, and it won't be long until we have terabyte computers. Digital camera models change like computers. They are doomed to obsolescence as the newer and faster cameras come out. Such is a market society! As this article is being written several 11 to 14 megapixel cameras are on the market.

The more expensive digital cameras offer robust camera construction, "burst mode" shooting that allows you to take a whole bunch of images in quick succession, and an interchangeable series of lenses. Many professional photographers use this DSLR type.

Today, we have basic "consumer" digital cameras that run from $200.00 USD to about $900.00 USD. Then, we enter the arena of the "prosumer" models, which cost from $900.00 USD to about $2,000.00 USD. Finally, there are the "professional" cameras, which start at about $3,500.00 USD and run all the way up to about $8,000.00 USD. So, there is a price range in the digital camera market for about everyone. As more and more people buy and use digital cameras, the cost will decrease. Digital seems to cost about 50% more to buy the camera, compared to film. But, if you shoot a reasonable amount of images, the less costly image processing will help pay for the additional cost of the camera.

In conclusion, buy as many megapixels as you can afford -- two-megapixel minimum. Check to see that it has an optical zoom. Make sure that the buffer will hold at least five or six pictures before transfer to memory card, and get a memory card type that you can afford.

Keep on shooting digital pictures!

see also

Coolpix Users Group Forum 
D1/D2 Users Group Forum
D100 Users Group Forum
D70 Users Group Forum
Digital Resources 
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